Pyrrhon is said by Diogenes Laertius to have studied first under some Megarian (hence skeptical antiphilosopher),  then under Anaxarchus the Democritean. When he was thirty-five or forty years old, Pyrrhon followed his master Anaxarchus and accompanied Alexander of Macedon to India. After an unknown length of time in India, Pyrrhon, perhaps forty-five or fifty years old, returned to Greece where he taught for perhaps forty years more and founded the school known as Pyrrhonism or Skepticism.  Like Socrates he wrote nothing, teaching more by personal example; as Diogenes says:
He had no positive tenet, but a Pyrrhonist is one who in manner and life resembles Pyrrhon (DL 9.70). 
We have only two sayings attributed directly to him:
1. Nothing really exists [= has a definite nature], but
human life is governed by mere convention.
2. No single thing is in itself more this than that (DL 9.61.).
Timon of Phlius, a first-generation student of Pyrrhon, seems to have written the earliest account of Pyrrhonism.  Pyrrhon, according to Timon, asked three questions: what is the nature of things? what is our position in relation to them? what, under the circumstances, should we do? The answers appear as a formulaic series of negations. Questions one and two are answered with three negative adjectives: things are adiaphora, 'nondifferent' or 'without distinguishing marks' (compare Skt. lak.sa.na-`suunya); astathmeta, 'nonstable' or 'without fixed essence' (compare Skt. anitya); and anepikrita, 'nonjudgable' or 'unable to be grasped by concepts' (compare Skt. avyaak.rta, 'indeterminable'; anabhilaapya, 'inexpressible'). As a result, says Timon:
Neither our perceptions nor our opinions are either true or false.
Question three is answered again with three negative adjectives: we should be adoxastoi, 'without opinions' (compare Skt. aprapa~ncita, 'undiscriminated') ; aklineis, 'without preferences' (compare Skt. upek.saa, 'indifference'); and akradantoi, 'without agitation' or 'firmly balanced' (compare Skt. `saanta, 'tranquil, steady'). Finally Timon rejects all possible verbal assertions in a summation of Pyrrhon's teaching that is virtually identical to the Buddhist catu.sko.ti:
We should say of each thing that it no more is than is not, than both is and is not, than neither is nor is not.
The purpose of this line of thought is spelled out:
Those who take this attitude, says Timon, will gain first detachment from language (aphasia), then imperturbality (ataraxia).
This brief summary could as easily describe the Praj~naapaaramitaa as the Pyrrhonist point of view. In the generations after Pyrrhon and Timon this central teaching was provided with a powerful dialectical support which is in turn remarkably similar to the Maadhyamika dialectic which arose in support of the Praj~naapaaramitaa point of view. This article will discuss selected topics which illustrate the parallelism between these two dialectical systems, will compare their purposes, and will consider the possibilities of historical connections between them. For the Greek side of the parallelism we will rely heavily on Sextus Empiricus, the Pyrrhonist encyclopedist of the second century A.D., and for the Indian on the Maadhyamikakaarikaas and Vigrahavyaavartanii of Naagaarjuna. 
Skeptics, like Maadhyamikas, taught no positive doctrines but devoted themselves to undermining the doctrines of other schools without exception. Sextus Empiricus states clearly the purpose of this destruction of opinions: through foresaking all opinions about the nature of reality, the Skeptic practitioner brings his mind into a state of suspension (epoche; compare Skt. vairaagya) wherein the various mind-states are experienced as nondifferent from one another (adiaphora; Skt. lak.sa.na-`suunya) . "Experience is a simple sequential flow of sense impressions, and all impressions are intrinsically of equal authority."  This "suspension" solidifies into an inner balance (arrepsia) in which the mind neither affirms nor denies, neither grasps at some impressions (having judged them 'good') nor pushes others away (having judged them 'bad'). This balance between affimation and negation expresses itself in a state of vocal and mental silence (aphasia, 'nonassertion' or 'nonspeech'; compare AAryadeva that nirvaa.na is "the extinction of all words" ), which ripens finally into freedom from phenomenal influence (apatheia, 'nonreactiveness, noninvolvement') and imperturbality (ataraxia), in which the mind experiences each present moment without either attachment or aversion.
This practice seems to correspond philosophically to the Maadhyamika rejection of linguistic categories as ontological reals and meditatively to the practice of vipa`syana, in which the flow of moments is experienced directly and simply, without anything either passional or theoretical added to them. It relates clearly to the Sutta Nipaata's description of the enlightened person:
He has not formed even the slightest opinion or conceptualisation about what is here seen, heard or thought (Sn., 802.).
From this opinion-freed stance, suspended between affirmation and negation,
arose the Skeptic and Maadhyamika dialectic. Some parallel passages will highlight the extraordinary similarity in basic attitude.
[Pyrrhon] denied that anything... is in itself more this than that (DL 9.61.).
Nothing is more this than that (OP 1.188.).
In this final truth there is neither this nor that. (Tilopa, Vow of Mahaamudraa.) 
Pure vision has neither limiting periphery nor fixed center. It cannot be shown as this or that... It has nothing to do with philosophical systems (Long-chen-pa). 
Things are neither this nor that (Seng Chao). 
Let us neither grasp at one thing nor flee from another (Pyrrhon, ap. DL 9.108.).
All things are by nature equally indeterminable, admitting of neither measurement nor discrimination. For this reason our sense experiences and beliefs are neither true nor false. Therefore we ought not to put our trust in them, but be without beliefs, disinclined to take a stand one way or the other (Timon ap. Aristocles.). 
The term suspension [epoche] is derived from the fact of the mind being held up or suspended so that it neither affirms nor denies anything (OP 1.196.).
I define nothing. [Or,] I determine nothing (OP. 1.197.).
Everything is undetermined... [meaning that] there is no preference among the things that are placed in opposition to one another (OP 1.198/9.).
I grasp at nothing; I cling to nothing (OP 1.201.).
"Suspense" [epoche] is a state of mental rest owing to which we neither deny nor affirm anything. "Quietude" [ataraxia] is an untroubled and tranquil condition of soul. And... quietude enters the soul along with suspension of judgment (OP 1.10.).
Let him not think something is better or worse or even the same as another (Sn. 795.).
The intention of the Buddha is this: my disciples [should be] free from passion for doctrine, free from attachment to doctrine, free from partisanship...... They do not quarrel about the nature of things (Mahaapraj~naapaaramitaa `Saastra, 63c.).
The Tathagata is one who has forsaken all reflections and discriminations (A.s.tasaahasrikaa Praj~naapaaramitaa, 137.).
Develop a mind that clings to nothing (Vajracchedikaa Praj~naapaaramitaa, 10.).
It is considered perverse to affirm or negate. It is said to be correct only when there is neither affirmation nor negation (Chi-tsang). 
[Right perception] means beholding all sorts of forms but without being stained by them as no thoughts of love or aversion rise in the mind (Hui Hai). 
This doctrine of indeterminacy (aoristia, 'lack of boundary or definition'; Skt. svabhaava-`suunyataa, 'emptiness of self-nature or essence') is simultaneously a critique of ontological claims of absolute Being or Nonbeing, of epistemological claims for knowledge (here aoristia becomes akataleepsia, 'ungraspableness', 'inability to be circumscribed by concepts'; compare Skt. anirvacaniiya, 'un-
definable', and nirvikalpa, 'transcending conceptual description'), and of the view that there is a language-reality isomorphism. The desire to escape from the web of language and confront experience directly led, in both schools, to a radical rejection of concepts, focusing on the central concept pair, being/non-being. This rejection was supported, in both schools, by a complex dialectic of the reducing or destroying type, designed, as Streng put it, "to redirect energies which were caught in the net of discourse."  In both cases the basic dialectical pattern is the dichotomy and dilemma type of reductio ad absurdum  with liberal use of regressus ad infinitum (Skt. anavasthaa) and special emphasis on the denial of partial identity, or sameness-difference dichotomy.  Finally it should be noted that for Sextus as for Naagaarjuna "'Is' refers only to what exists through own-nature...," and "what exists by means of own-nature is permanent, fixed, unproduced, unstopped, and unchanging."  Of many possible examples we will use as paradigm the dialectic against causality. 
Both schools apply the sameness-difference dichotomy: if cause and effect are the same, then the terms are meaningless; if they are different, there can be no contact or continuity between them. Naagaarjuna's formulation is succinct:
It is not possible indeed for a cause and effect to be
identical. But again it is not possible for them to be different.
If the cause and effect were identical, there would be an identity of the producer and the produced. If they were different, however, then the cause would be the same as a non-causal cause (MK 20. 19-20.).
Sextus formulates the argument at greater length, providing us meanwhile with the fullest explication of the "denial of partial identity":
If there exists any cause of anything, either it is separate from the matter affected or it co-exists with it; but neither when separate from it nor when co-existing with it can it be the cause of its being affected, as we shall establish; therefore no cause of anything exists. Now, when separated from its matter obviously it is not a cause, since the matter with respect to which it is termed a cause is not present, nor is the matter affected, since that which affects it is not present with it. But if the one is coupled with the other [then the arguments against contact apply:]... In order that a thing may act or be acted upon, it must touch or be touched; but, as we shall establish, nothing can either touch or be touched; therefore neither that which acts nor that which is acted upon exists. For if one thing is in contact with another and touches it, it is in contact either as a whole with the whole, or as a part with a part, or as a whole with a part or as a part with the whole... Now it is according to reason that a whole does not touch a whole; for if whole touches whole, there will not be contact but the union of both... Nor again is it possible for part to touch part. For the part is conceived as a part in respect of its relation to the whole, but in respect of its own limited extent it is a whole, and for this reason again either the whole part will touch the whole part, or a part of it a part. And if the whole touches the whole, they will be unified and both will become one body; while if with a part it touches a part, that part again, being conceived as a whole in respect of its own limited extent,
will either touch as a whole the whole part, or touch a part of it with a part -- and so on ad infinitum (APh 252-261.). 
Cause and effect, then, can be neither the same nor different, and on the principle of the excluded middle there is no other possibility.
Both Sextus (in an argument going back to Parmenides) and Naagaarjuna reject the possibility that the cause somehow "contains" the effect, because in that case, says Sextus, "[the effect] is already in existence and being already in existence it does not become, since becoming is the process toward existence." (APh 1.226.) And as Naagaarjuna put it: "If a cause is a void with respect to an effect, how could it give rise to the effect? If, on the other hand, a cause is not a void with respect to an effect, how could it give rise to the effect?" (MK 20.16.) That is, if the cause does not contain the effect, the effect cannot arise from it; if it does contain the effect, then the effect already exists and cannot be said to arise from it.
Nor can we get around the problem by saying that the effect is self-produced, or reduplicated, for if the nature of the cause is to reduplicate itself, then the effect, being a duplicate of the cause, will also have that nature, will also reduplicate itself, and so on ad infinitum; the world will be filled with identical objects. The Maadhyamika version is found in the first alternative of MK 1.1: "At nowhere and at no time can entities ever exist by originating out of themselves...," and Candrakiirti's commentary on the passage: "There will be no conceivable limit to this process of reduplication" (MKV, p. 14). Sextus makes he same point:
One thing is not able to become two... for if one is able to become two, then each of the two, being one, will produce two, and each of the four, being one, will make two, and similarly each unit of the eight, and so on ad infinitum (APh 1.220/1).
Another Skeptic and Maadhyamika approach to the critique of causality focuses on the problem of time, or succession, and establishes that cause and effect can exist neither simultaneously nor successively, and again, by excluded middle, there is no other possibility. Sextus and Naagaarjuna state the argument in almost identical terms; first Sextus:
If anything is the cause of anything, either the simultaneous is the cause of the simultaneous, or the prior of the posterior or the posterior of the prior ... Now the simultaneous cannot be the cause of the simultaneous owing to the co-existence of both and the fact that this one is no more capable of generating that one than is that one of this one, since both are equal in point of existence. Nor will the prior be capable of producing that which comes into being later; for if, when the cause exists, that where of it is cause is not yet existent, neither is the former any longer a cause, as it has not that whereof it is the cause, nor is the latter any longer an effect, since that whereof it is the effect does not co-exist with it. For each of these is a relative thing, and relatives must necessarily co-exist with each other, instead of one preceding and the other following.
It only remains for us, then, to say that the posterior is the cause of the prior; but this is a most absurd notion... for we shall have to say that the effect is older than what produced it and consequently is not an effect at all since it is without that whereof it is an effect (APh 1.232-235.).
If the cause gives to the effect a causal nature before extinguishing itself, then there will be a dual causal form of the given and the extinguished. If however the cause does not give the effect a causal nature before extinguishing itself, then the effect, rising after the cause extinguishes itself, will have no cause. If again the effect and the assemblage (inc. cause) appear together, then it would follow that the producer and the produced are contemporaneous. Moreover, if the effect appears prior to the assemblage (of conditions containing the cause), then it, without cause and relational condition, will have a non-causal nature (MK 20.5-8.). 
Finally, in a most remarkable parallel, Sextus and Naagaarjuna use precisely the same exemplum -- wood and fire -- to sum up some of the difficulties in the concept of causality. Sextus says:
If fire is the cause of burning, either it is productive of burning by itself and using only its own power, or it needs for this purpose the cooperation of the burning material, And if it produces the burning by itself, being sufficient of its own nature, then, since it always possesses its own nature, it ought to have been continually burning. But it does not burn always, but burns some things and does not burn others; therefore it does not burn by itself and by using its own nature. But if it does so in conjunction with the suitability of the burning wood, how can we assert that it, rather than the suitability of the wood, is the cause of the burning? For just as no burning takes place if the fire is non-existent, so also no burning takes place if the suitability of the wood is absent. Thus also, if it [fire] is the cause because the effect occurs when it is present and does not occur when it is absent, the suitability [of the wood] too will be the cause for both these reasons (APh 1.242-243.).
This exemplum argues (1) that a cause produces nothing by itself and thus is not a cause, and (2) that a cause is as much an effect as it is a cause, and an effect is as much a cause as it is an effect -- in other words, that it is impossible to distinguish between cause and effect and as impossible to call them one (the identity-difference dilemma again).
Naagaarjuna devotes an entire chapter of the Kaarikaas to the same exemplum, with the same implications evidently in mind:
If wood is the same as fire, then likewise the doer and
his deed will be identical. If fire is distinct from wood, then it will exist without
If there is no cause for burning, then fire should burn constantly. And there will be no purpose in fire to start (i.e., to burn) again and it will then be without a function.
Being unrelated to an other, it (i.e., fire) will be something without a cause for burning. Moreover, it will follow that a constantly burning fire would have no purpose of starting (i,e., burning) again.
Thus if it is granted that there is wood in the burning (process) and that only wood is burning, then by what means will it burn? (MK 10. 1-4.).
Fire which is distinct from wood will unite with the
latter... if and only if the two have mutually distinct identities.
If fire is dependent on wood and wood on fire, then each one must have a prior completed state... to which the other depends (MK 10.7-8.).
Fire does not exist in dependence on wood nor does it exist by non-dependence on wood. Likewise, wood does not exist by dependence on or non-dependence on fire (MK 10.12.).
The cause cannot exist without the effect, therefore, the effect is the cause of the cause; each precedes the other in a logical circularity ad infinitum. Finally, cause and effect can neither be logically conceived as the same nor as different, and there is no third possibility.
We have looked at only one topic of the many to which Sextus and Naagaarjuna applied their dialectic. The types of arguments used against causality easily can be converted to critiques of other topics and were. As Robinson said, "Naagaarjuna states explicitly that the form of his arguments may be abstracted from their content, that other proofs may be performed by substituting different terms within the same pattern. This comes rather close to recognition of the principle of variables."  Precisely the same may be said of Sextus, who works with the same rather formulaic patterns of argumentation and substitutes terms freely to focus the dialectical thrust against one area of conceptualization after another. Parallels as detailed and extensive as that in the critique of causality can be arrayed from Sextus' and Naagaarjuna's arguments against origination and destruction, motion and rest, substance and attribute, time and space, potentiality and change. Due to limitations of space we will turn instead to consideration not of these interchangeable topics but of certain themes and methods which are omnipresent in both Sextus' and Naagaarjuna's argumentation.
Naagaarjuna uses the infinite regress in his critiques of origination, duration, and destruction (MK 7.18-19,), and of motion through continuous space (MK 2.1-2, 12-14), and implies, but does not make specific, an infinite regress in his critique of the substance-attribute relationship.  Sextus for his part had inherited a rich harvest of Eleatic arguments from infinite regress (all the arguments which can confidently be ascribed to Zeno Eleaticus were of this type!) and uses them against origination, duration, and destruction, and against motion through either continuous or particulate space (for example, AP 3.109 ff.; OP 3.71 ff.; APh 2.37 ff., 2.320, and so on). In addition to these uses familiar from Eleatic thought, both Sextus and Naagaarjuna have a critique of proof from infinite regress of premises, which we will present as an example of the type.
The thing adduced as proof of the matter proposed needs a further proof, and this again another, and so on ad infintrum so that the consequence is suspension of judgment, as we possess no starting point for our argument. (OP 1.166-167).
And if, for you, there is a source (of knowledge) of each and every object of proof, then tell how, in turn, for you there is proof of these sources.
If by other sources (of knowledge) there would be the proof of a source -- that would be an "infinite regress"! In that case neither a beginning, middle, nor an end is proved (VV 31/32.). 
Both Skeptics and Maadhyamikas criticized relational existence (or svabhaava claims for relatives) and in remarkably similar spirit. On the Maadhyamika side, the rejection of the own-being of things involved in relational existence (pratiitya-samutpaada) is the 'signpost' (as Parmenides might have put it) of emptiness: "Neither produced nor maintained by itself, a thing by itself is nothing at all. And this is equivalent to the insight into the emptiness of all dharmas."  As Murti says, "Things that derive their being and nature by mutual dependence are nothing in themselves; they are not real.... What is relative is subjective, unreal.... No phenomenon, no object of knowledge, escapes this universal relativity."  As Naagaarjuna says: "Any existence which is relational is indeed neither identical to nor different from the related object" (MK 18.10). That is to say, a relational "entity" is not a real (svabhaava) entity, for if it were, the categories of identity and difference would apply to it. We may compare Chi-tsang:
Dharmas are neither existent nor non-existent, because they are produced by causes. If existence is not existence by its own nature but depends on causes to be existent, we know that although it (appears to) exist, it has no true existence. Since it has no true existence, it cannot be called existence in the real sense, although it (appears that it) exists." 
As Sextus Empiricus put it:
Relatives are only conceived and do not exist (APh
Relative terms are in and by themselves unknowable (DL 9.88.).
Since all things are relative, we shall suspend judgment regarding their independent and real essence (OP 1.135.).
"This principle, " says Murti, "is enunciated in almost every chapter of the Maadhyamika Kaarikaas,"  and the same may be said of Sextus' monumental work, where the denial of the ontological integrity of relatives, like the regressus ad infinitum, is worked into practically every argument.
This dialectical mode by itself could accomplish the whole job of undermining svabhaava claims on experience. Since every proposition exists, or has meaning, only in relation to its negation, every proposition is necessarily relational; thus the danger of grasping at yes or no, being or nonbeing: assert one and you call up its negation. As Suzuki put it:
"A" cannot be itself unless it stands against what is not "A"; "not-A" is needed to make "A" "A", which means that "not-A" is in "A". 
Naagaarjuna makes this explicit in the Ratnaavalii:
When this exists, that exists, as 'long' exists when 'short' exists. 
Thus the Ch'an master Huang Po advises:
Beware of clinging to one half of a pair. 
And Sextus Empiricus:
Every assertion is annulled by an equal and opposite assertion (OP 1.202.).
In addition to annulling all statements, the principle of relationality applies to every act of perception, as Sextus makes clear:
This statement is twofold, implying firstly relation to the thing which judges (for the external object which is judged appears in relation to that thing), and in a second sense in relation to accompanying percepts, for instance the right side in relation to the left (OP 1.135.).
Thus anything perceived is "unreal" (in terms of the rigorous definition which both Sextus and Naagaarjuna put on "being"), as is any perceiver, for what is perceived "exists" only in relation to the perceiver, and the perceiver only in relation to the perceived. Naagaarjuna has precisely the same argument, rejecting seeing and the seen on the ground that they "exist" only in relation to one another, and then, by the system of "variables," applying the same proof to the other senses, including mind (MK 3.6, 8). We may compare `Saantideva:
The imagination and the thing imagined are both mutually
dependent (BCA 9.109.).
If an object is dependent upon knowledge, what has become of the reality of knowledge? Likewise, if knowledge is dependent upon that which is to be known, what has become of the reality of that which is to be known? Because of mutual dependence, the reality of both is nullified (BCA 9.112-113.).
There are, of course, countless possible formulations of experience in terms of relative pairs, and no formulation can escape those terms. Naagaarjuna rejects causality on the ground that cause and effect are a dependent pair (MK 1), and so did the Pyrrhonists:
Causes too they destroy in this way: a cause is something relative, for it is relative to what can be caused, namely the effect. But things which are relative are merely objects of thought and have no substantial existence (DL 9.97.).
Again, both Sextus and Naagaarjuna employ the argument from relationality to deny the concept of an absolute or ultimate being. Naagaarjuna does this in his assertion that "if nirvaa.na and sa^msaara lack own-nature [since the concepts are dependent on one another], they are neither different nor identical."  Sextus has a similar passage evidently aimed against the Platonists:
Do things which exist "in themselves" differ from relative things, or not? If they do not differ, then they too are relative; but if they differ, then, since everything which differs is relative to something (for it has its name from its relation to that from which it differs), things which exist "in themselves" are relative too (OP 1.137.).
The universality of relation (which is perhaps the only positive ontological doctrine taught by either Sextus or Naagaarjuna), combined with the denial of real-being to relatives, effectively disqualifies our experience from any metaphysically definitive verbal description whatever. But it would be a mistake to think that the dialectic finally emerges as a kind of triumphant principle in itself. On the contrary, both Sextus and Naagaarjuna rejected any attempt to find in the dialectic the security which the dialectic itself has removed from other concept-systems. For both, the dialectic is an "uroboric"  or self-destroying path: first it wipes out conceptual proliferation (Skt. prapa~nca, Grk. typhos), the habit of projecting linguistic distinctions ontologically, then it erases itself too. To put it differently: the dialectic disappears at the same moment when opinions disappear: opinions and the rejection of opinions are a dependent pair, and when opinions are gone, it is no longer possible for a rejection of opinions to exist.
This uroboric self-destruction is what is known in the Buddhist tradition as `suunyata-`suunyataa, 'the emptiness of the emptiness doctrine'. As Candrakiirti put it:
Emptiness is not a property, or universal mark, of entities, because then its substratum would be nonempty, and one would have a fixed conviction (d.r.s.ti) about it. In fact, it is a mere medicine, a means of escape from all fixed conviction. It is taught so that we may overcome attachment, and it would be a pity if we were to become attached to it. It is not a positive standpoint, but a mere turning away from all views and thought-constructions. To treat it as an object, and to oppose it to non-emptiness, is to miss the point (Prasannapadaa, 12.). 
Similarly, Sextus Empiricus says that the various Skeptic mottos "are confuted by themselves, seeing that they themselves are included in the things to which their doubt applies" (OP 1.206.). Thus the Skeptic motto, "Nothing is true," means "Nothing is true including the statement that nothing is true." "Nothing is comprehensible" means "Nothing is comprehensible including the statement that nothing is comprehensible."
It is here that we encounter, among both Skeptics and Maadhyamikas, what appears to be a breach of the principle of the excluded middle. As Streng says,
"They do not accept the condition that in refuting one view they must affirm the contrary."  Sextus defends his practice exhaustively, offering four different arguments to his hypothetical Stoic opponent, who claims, "If the statement that nothing is true is not true, then we must accept its converse, that something is true." First Sextus says in regard to the negative slogans:
We do not employ them by way of authoritatively explaining the things with reference to which we adopt them, but without precision and, if you like, loosely; for it does not become the Skeptic to wrangle over expressions. (OP 1.207.) 
The negative generalizations, in other words, are teaching devices, not assertions about reality. Naagaarjuna likewise says that the emptiness terminology is not meaningful, but a teaching device:
Nothing could be asserted to be `suunya, a`suunya, both `suunya and a`suunya, and neither `suunya nor a`suunya. They are asserted only for the purpose of provisional understanding. (MK 22.11.)
Second, Sextus upholds by various analogies the validity of a negative generalization which also negates itself:
[The dialectic] is like fire, which, after consuming the
fuel, destroys itself also. (AL 2.480.)
[And also it is like] aperient drugs, which do not simply eliminate the humours from the body, but also expel themselves along with the humours. (OP 1.206.)
And again, just as it is not impossible for the man who has ascended to a high place by a ladder to overturn the ladder with his foot after his ascent, so also it is not unlikely that the Skeptic after he has arrived at the demonstration of his thesis by means of the argument proving the nonexistence of proof, as it were by a step-ladder, should then abolish this very argument. (AL 2.480-481.)
Remarkable parallels to these passages can be found in Buddhist and other texts. Candrakiirti, like Sextus, compares the dialectic to a medicine which, having cured the disease, dissolves itself.  We may compare a statement by the "crypto-Buddhist" Vedaantin Ramana Maharshi with Sextus' fire analogue:
The thought 'who am I?' will destroy all other thoughts and, like the stick used for stirring the burning pyre, it will itself in the end get destroyed. Then there will arise self-realization. 
And Wittgenstein, in the famous passage at the end of the Tractatus, presents an exact (intentional?) echo of Sextus' ladder analogy:
My propositions are all elucidatory in this way: he who understands me finally recognizes them as senseless, when he has climbed out through them, on them, over them. (He must, so to speak, throw away the ladder, after he has climbed up on it.) He must surmount these propositions; then he sees the world rightly. 
Related also are the common Buddhist imagery of the dharma as a raft to be thrown away once one has reached the other shore, and Naagaarjuna's statement that his refutation is like one phantom destroying another (VV 23/4.).
In stressing the reflexive nature of their rejection of views, both Sextus and
Naagaarjuna attempt to prevent the student from adopting indeterminacy (aoristia) or emptiness (`suunyataa) as a supposedly superior point of view. The dialectic must not be clung to anymore than the assertions which it has refuted. It does not describe an ultimate reality; it is not a premise or a set of premises, but a method of analysis which can be applied to premises. It is a unique kind of philosopical discourse designed to eliminate philosophical discourse. Here Sextus and Naagaarjuna reveal themselves as practical teachers. Their dialectic is not an exercise in logic; it is functional, experiential. Its value, like that of a medicine, is not in itself, but in its ability to do a job.
Sextus proposes, in addition, a third justification of the reflexive negations which is worth inspecting in detail. He presents a debate with a Stoic opponent (AL 453 ff.). First Sextus denies proof, by the critique of relational existence: Relative things do not exist. Proof is relative both to the object proven and to the mind which apprehends the proof. Therefore, proof, being relative, does not exist except as an imaginative construct.
The Stoic replies: If this argument does not constitute a proof of the non-existence of proof, then it cannot convince us that proof does not exist; but if it does constitute a proof (of the non-existence of proof), then it demonstrates that proof does in fact exist: it demonstrates the opposite of what it asserts. The Skeptic reply is in parallel: If the argument does not constitute a proof (that proof does not exist) then it does not demonstrate the existence of proof; if it does constitute a proof (that proof does not exist), then the non-existence of proof, having been proven, must be accepted.
It is obvious that what we have here is not a proof of anything but rather a conundrum similar to the Megarian one about lying. For Sextus the real point of this circular dispute about proof is that it demonstrates (not proves) that, in his terms, proof neither exists nor does not exist: the whole matter about proof simply does not make sense. Sextus concludes, "[One can] no more affirm than deny proof" (AL 2.472.).
In the Vigrahavyaavartanii (esp. 1-4, 23-26) Naagaarjuna engages in a parallel debate. His opponent argues:
Your statement (viz., that nothing has self-existence),
itself being without self-existence, is not able to discard self-existence.
But if that statement has its own self-existence, then your initial proposition is refuted. (VV 1-2.)
This, of course, is precisely parallel to the Stoic attack on Sextus; Naagaarjuna's opponent says that if his proposition is true, then it demonstrates the opposite of what it claims: if the argument does not exist it can prove nothing; but if it does exist, then, while logically disproving existence it empirically demonstrates it. Naagaarjuna replies:
This statement (viz., that nothing has self-existence) is not self-existent Just as a magically formed phantom could deny a phantom.... Just so (is) this negation (VV 24, 23.).
The opponent then bases himself on the law of the excluded middle: "if the phenomena which your argument negates lack self-existence, then that which lacks self-existence has been negated; consequently, by excluded middle, that which has self-existence has been proven." Naagaarjuna replies with what seems to be a bald rejection of the principle of the excluded middle:
If I would make any proposition whatever, then by that I
would have a logical error;
But I do not make a proposition; therefore I am not in error. (VV 29.)
Finally, Sextus adds a fourth point which removes the question from dialectical treatment altogether. The Skeptic, says Sextus, cannot really make any statements about reality, such as that proof or anything else does or does not exist; he can only report what is present to his consciousness at any moment:
Of none of our...statements do we positively affirm that
the truth is exactly as we state it, but we simply record each fact, like a chronicler, as
it appears to us at the moment (OP 1.4).
For this is not a dogmatic assumption, that is to say assent to something nonevident, but an expression indicative of our own mental condition...This he says simply by way of announcing undogmatically what appears to himself regarding the matters presented, not making any confident declaration, but just describing his own state of mind (OP 1.197.).
A present state of mind is simply a fact and cannot be affected by argument. All that is really being said in the debate about proof is that the Stoic has a present impression for proof, and the Skeptic a present impression against it. The same situation results when one person says a room is cold and another that it is warm: neither has said anything about an external reality.
Nonadditive attention to the present mental state is an activity of the condition of epoche, or Skeptic suspension, and results in part from the realization of what Sextus calls the "equipollency of yes and no." As he explains,
With regard to any object presented, there has arisen both amongst ordinary people and amongst the philosophers an interminable conflict of views because of which we are unable either to choose a thing or to reject it, and so fall back on suspension. (OP 1.165.)
Sextus' "interminable conflict of views" is precisely equivalent to what Murti calls "the interminable and total conflict in reason"  and which he identifies as the motivation behind both the Buddha's noble silence and the Maadhyamika dialectic.
So happily does Sextus refrain from identifying the negative dialectic as a position to which he adheres that he says he rejoices if his opponent presents a positive proof just as convincing as Sextus' negative -- for then the futility of believing and the necessity of taking the middle position between yes and no becomes obvious to all. (AL 2.476/7.)
The purpose of the Maadhyamika dialectic is clear up to a point. It aims, Naagaarjuna said, at the pacification of prapa~nca, or conceptual proliferation (MK 25.24); this pacification, says Candrakiirti, is nirvaa.na.  When the mind no longer grasps at notions of real or unreal entities (bhaava or abhaava), it is, says Naagaarjuna, in the state of nirvaa.na (Ratnaavalii 1.42.).  The Maadhyamika then is a "transformational dialectic" which "purports to move consciousness beyond any and all conceptual structures, beyond any form of discourse, beyond any natural or philosophical language, beyond any ontology."  The mind's attempt to project linguistic categories ontologically, or to make experience conform to a concept-system, is the source of its suffering and delusion; by developing the clarity and courage to live "without thought coverings" (as the Heart Suutra says), the aspirant "overcomes what can upset, and in the end attains to Nirvaa.na."  Many other texts, from the Sutta Nipaata to Zen, make the same assertion: that the concept-freed mind is the Buddha mind is enlightenment.
Disagreement arises with the question whether this concept-freed mind means a radically transcendent or absolute state on the one hand or a certain way of participating in phenomenality, with no suggestions of absolutism, on the other.
As to the purpose or result of Sextus' dialectic there is virtually no agreement among published opinions. In recent years a variety of contradictory answers have been proposed, all, I think, seriously in error.  It is odd that there should be so much disagreement (and so much confusion) on a matter on which Sextus expresses himself with utmost clarity. The relevant passages deserve to be quoted in full:
Skepticism is an ability, or mental attitude, which
opposes appearances to judgments in any way whatsoever with the result that, owing to the
equipollence of the objects and reasons thus opposed, we are brought firstly to a state of
mental suspense (epoche) and next to a state of "unperturbedness" or quietude
(ataraxia). (OP 1.8.)
The originating cause of Skepticism is, we say, the hope of attaining quietude (ataraxia). (OP 1.12.)
An "End" is "that for which all actions or reasoning are undertaken, while it exists for the sake of none"; or otherwise, "the ultimate object of appetency." We assert still that the Skeptic's End is quietude (ataraxia) in respect of matters of opinion and moderate feeling in respect of things unavoidable... For the man who opines that anything is by nature good or bad is for ever being disquieted: when he is to be tormented by things naturally bad and he pursues after the things which are, as he thinks, good; which when he has obtained he keeps falling into still more perturbations because of his irrational and immoderate elation, and in his dread of a change of fortune he uses every endeavour to avoid losing the things which he deems good. On the other hand, the man who determines nothing as to what is naturally good or bad neither shuns nor pursues anything eagerly; and in consequence he is unperturbed... The Skeptics were [once like other people] in hopes of gaining quietude by means of a decision regarding the disparity of the objects of sense and of thought, and being unable to effect this they suspended judgment; and they found that quietude, as if by chance, followed upon
their suspense, even as a shadow follows its substance. We do not, however, suppose that the Skeptic is wholly untroubled; but we say that he is troubled by things unavoidable; for we grant that he is cold at times and thirsty, and suffers various affections of that kind. But even in these cases, whereas ordinary people are afflicted by two circumstances -- namely by the affections themselves and, in no less a degree, by the belief that these conditions are evil in nature -- the Skeptic, by his rejection of the added belief in the natural badness of all these conditions, escapes here too with less discomfort. Hence we say that while in regard to matters of opinion the Skeptic's End is quietude, in regard to things unavoidable it is "moderate affection" (OP 1.25-30.). 
It is interesting to note that `Saantideva explains the purpose of the dialectic in terms virtually identical to Sextus':
When neither existence nor non-existence is presented again to the mind [= Sextus's state of epoche], then, through lack of any other possibility, that which is without support becomes tranquil (BCA 9.35.).
Finally it is hard to identify any significant difference, in purpose and effect, between Sextus' dialectic and Naagaarjuna's. If the pacification of conceptual proliferation (Candrakiirti) and the suppression of belief in real entities or their absence (Naagaarjuna) constitute nirvaa.na for an Indian or a Chinese, it is hard to say why they should not constitute nirvaa.na for a Greek as well. And if Conze is right in saying that "The teaching of the sameness of everything cannot fail to promote the virtue of evenmindedness" and "the attitude of non-assertion... alone can assure lasting peace,"  then I can see no reason (beyond cultural prejudice) why his remarks should apply less to Greeks than to Indians and Chinese.
In short, Sextus' dialectic, like that of Naagaarjuna, is a "transformational dialectic," designed to release the mind from bondage to "some form of consciousness, some ontology, some intelligible or rational structure which it has not seen through or called into question,"  an "analytical meditation in which the formal conditions of all discourse or any possible world are themselves shown to be conditioned and not independent, absolute, or self-existent." 
It would be worthwhile for the reader to compare the italicized part of Sextus' statement of purpose, in the preceding long quotation, with any one of the classic formulations of the Buddha's Four Noble Truths, as they are more or less identical -- or rather, Sextus' passage might function as an explication of the Four Truths. In both cases, the motivation for entering the path is to escape from suffering, while the genesis of suffering is identified as the habit of discriminating between good and bad, avoiding the bad, pursuing the good and, once one has gotten it, trying to hang onto it. In both cases the way out of suffering is based on freeing oneself from this discrimination and cultivating a moderate involvement in phenomena (metriopatheia; compare the 'middle way').
Sextus, of course, does not promise complete freedom from pain; he does not, for example, promise that the Skeptic's body will never undergo painful injury. He promises freedom from the adventitious and avoidable pain of
conceptually condemning and emotionally fleeing the unavoidable pain of the body. Many Buddhist teachers have interpreted the third Noble Truth (nirodha) in this way: pain does not cease, only our aversion from it. Sextus' Skeptic who gets cold or thirsty and simply entertains the cold and thirst as indeterminate data without judging them evil is much like the Hiinayaana Buddha who dies of a stomachache without thinking it an evil. (Mahaa-parinibbaana-sutta, IV, 21.).
Furthermore, Sextus' emphasis on the direct, nonconceptual relationship with the present moment, his "acquiescing in the phenomena" or using the present moment as one's "criterion for action" (OP 1.21-24) , but "without intense goal-orientation (prosklisis) or intense emotional involvement (prospatheia)" (OP 1.230) resembles the simple and nonjudgmental "mindfulness" (Pali sati) of Buddhism. Pyrrhonism, like Buddhist mindfulness practice, is "the return" from concept-motivation "to life itself as the only guide."  The Skeptic, Sextus says, is guided by thirst to drink and by hunger to food (OP 1.24, 238, et al.), to which we might compare the common Zen definition of enlightenment as the state in which one eats when hungry and sleeps when tired. 
It is important to remember that Buddhist texts present various descriptions or definitions of enlightenment. It would be very hard to differentiate Sextus' ataraxia from the less flamboyant of these, those found in Theravaadin, Maadhyamika, Mahaamudraa, Ch'an and Zen texts, many of which talk of enlightenment in terms much like Sextus' epoche, arrepsia, ataraxia, and aphasia. On the other hand, the vision of the Vairocana Tower in the Ga.n.davyuuha could not be found in Sextus and bears little resemblance to any state of mind which he discusses; but neither could it be found in the Paali Canon, or in Naagaarjuna or Hui Neng.
It might be objected that there is too little of the ethic of compassion and loving kindness in Sextus, but that is merely apparent. Naagaarjuna does not deal with such matters in dialectical works either; he and Sextus are presenting the praj~naa aspect of the praj~naa/karu.naa linkage, and what Conze says of Maadhyamikas should apply equally to Skeptics, that "if a peaceful attitude toward others is the test of religious zeal, it must be greatly furthered by a doctrine which tells us not to insist on anything nor to assert anything."  As a modern Zen teacher explains the praj~naa/karu.naa relationship, "Love is the natural functioning of wisdom."  A passage in Diogenes Laertius suggests that the Skeptics made the same discovery:
According to some authorities the end proposed by the Skeptics is detachment (apatheia); according to others gentleness (Praaotees). (DL 9.109.)
In 326 B.C. Alexander of Macedon entered the religious center of Taxila in north-west India and remained there for some months; with him were three
philosophers, Pyrrhon, his master Anaxarchus, and Onesicritus the Cynic. It is probable that these philosophers were taken along for the purpose of studying local systems of thought, as biologists were brought to study animal and plant specimens. Strabo reports that Onesicritus was sent to converse with Indian "sophists" (Strabo 15.1.63), and Pyrrhon also, in the months in Taxila, had contact with some of his Indian counterparts (DL 9.63.).
Megasthenes, a Greek historian who, about a generation later, spent a decade at Paa.taliputra, wrote a description of Indian philosophy as he knew it and attributed the following, among other teachings, to the "Brachmanes":
They believe that nothing that happens to mankind is good or bad, for otherwise some would not be grieved and others delighted by the same things, both having dream-like notions. (Strabo 15.1.59.). 
Pyrrhon may well have heard similar things in Taxila, and Diogenes Laertius represents him as teaching, after his return from India, that
there is nothing good or bad by nature, for if there is anything good or bad by nature, it must be good or bad for all persons alike.... But there is no good or bad which is such to all persons in common; therefore there is no such thing as good or bad by nature (DL 9.101.).
It is, then, a great temptation to say that Pyrrhon imported into Greece teachings from the East; and it is a temptation that many have succumbed to.  Burnet even refers to Pyrrhon as "a sort of Buddhist arhat."  But in fact it seems that Pyrrhon had imbibed the main attitudes of his philosophy from Greek teachers, before the visit to India; scholars who are looking for large-scale Indian influence on Pyrrhon can find it only at the cost of ignoring the internal dynamic of the Greek tradition.
The relationship (or set of possible relationships) between Pyrrhonism and Indian philosophy is complex. The situation can be summarized through a series of questions.
1. Did Pyrrhon derive from Indian teachers the basic stance or attitude of his teachings? This is a view commonly enough accepted which I hope to show is clearly unjustified, in light of a survey of Pyrrhon's philosophical lineage.
Pyrrhon was educated in the lineages of both the great proto-Skeptics of the Greek Tradition, Socrates and Democritus. From his first teacher, Bryson the Megarian (hence both Socratic and Neo-Eleatic), he learned the infinite regress reductiones of Zeno, the inductive Socratic elenchus and the dichotomy-and-dilemma conundra of the Megarians themselves, in short, the whole critical apparatus of his time.
Subsequently Pyrrhon became a student of Anaxarchus of Abdera, who in turn was a pupil either of Democritus or of a Democritean (DL 10.58.). Democritus had already, in the fifth century B.C., taught the nondifference of phenomena and the eudaimonistic approach to philosophy -- philosophy as a path to a tranquil attitude beyond the effect of phenomenal change:
The end of action [according to Democritus] is tranquillity, which is not identical with pleasure, as some by a false interpretation have understood, but a state in which the mind continues calm and strong, undisturbed by any fear or supertition or any other emotion. This he calls well-being, and many other names (DL 9.45.).
Stobaeus in fact attributes to Democritus the term ataraxia (fr. 68 A 167), which may have descended through the Democritean lineages to both Epicurus and the Pyrrhonists. This detached condition, which Democritus also called atthambia ('inability to be astonished or frightened'), is obviously similar to the apatheia ('nonreactiveness') taught by the Cynics, and both are substantially the same as the condition which the Praj~naapaaramitaa literature attributes to one who knows emptiness:
One who is convinced of the emptiness of everything is not captivated by worldly dharmas, because he does not lean on them. When he gains something he does not rejoice, when he does not gain it he is not depressed. Fame does not make him proud, lack of fame does not depress him. Pleasure does not attract, pain does not repel him. One who in such a way is not captivated by the worldly dharmas is said to be one who knows emptiness (`Sik.saasamuccaya, 264.). 
The basis for this condition in the Praj~naapaaramitaa-Maadhyamika tradition is the realization that linguistic categories are unable to contain our shifting and thus indefinable experience. In Democritus also we find that imperturbability results from an awareness that linguistic categories don't correspond to anything. As Robin says, for Democritus what we call 'knowledge' is a "sorte d'habitude sociale r'esultant d'une 'convention' tacite, qui a pour object de remplacer par un syste'me de noms, d'usage commun et de signification permanente, le flot mouvant de nos impressions, toujours individuelles, changeant avec l'etat de notre corps et avec ses relations aux objects ext'erieurs, dont l'etat et la constitution sont eux-memes perp'etuellement changeant."  Democritus taught:
The qualities of things exist merely by convention; in
nature there is nothing but atoms and the void (DL 9.45.).
Opinion says hot or cold, but the reality is atoms and empty space (DL 9.72.).
The criticism of the idea of language-reality isomorphism which is expressed by Hermogenes in Plato's Cratylus is generally attributed to Democritus himself:
I cannot convince myself that there is any principle of correctness in names other than convention and agreement. Any name which you give, in my opinion, is the right one, and if you change that and give another, the new name is as correct as the old.... For there is no name given to anything by nature; all is convention and habit of the users (Crat. 384c.).
The idea of truth, once we have seen through the reification of language, becomes beside the point. "Of truth we know nothing, for truth is in a well" (DL 9.72.).
Democritus' linguistic nominalism was an aspect of the full-scale phenomenalism which his teacher Leucippus had begun and he completed. Leucippus taught that:
Everything comes to be according to imagination and opinion, not according to truth; it is like the appearance of an oar thrust in water [which appears to be bent though it is not] (A 33.).
Democritus first taught a double truth (noumenal and phenomenal), and in his ethics emphasized the acceptance of the phenomenal for practical purposes:
Everything is only appearance. (A 48b.)
The appearance is truth. (A 101.)
The Democritean tradition, aside from its noumenal atomism, is a phenomenalistic relativism;  Pyrrhon omitted the dogmatic atomism and retained the phenomenalism, as "Buddhism positively negated ontology and took to phenomenalism."  From the impossibility of a definite ontology comes the ethics of suspension or ataraxia. Democritus (B 172) already provides a source for Pyrrhon's declaration that "there is nothing good or bad by nature but only by appearance."
Democritus' method of gaining awareness of the mere conventionality of linguistic categories, the nondifference of "things," involved, in addition to rational thought, cultivation of solitude and concentration on death, both methods basic to the development of such insight in Buddhism also:
He would train himself, says Antisthenes, by a variety of means to test his sense-impressions by going at times into solitude and frequenting tombs (DL 9.38.).
Furthermore, Democritus had a distinctly dialectical side, as in his criticism of Protagoras' statement that all appearances are true: if it should appear to someone that no appearances are true, then that, being an appearance, is true and contradicts the original thesis (A 13.). Democritus' combination of aporetic with reflexive dialectic was learned by his students Protagoras and Metrodorus. Protagoras stated that one can argue both sides of any question equally well -- including the question whether one can argue both sides of a question equally well (A 20.). And Metrodorus of Chios, also a student of Democritus, "used to declare that he knew nothing, not even the fact that he knew nothing" (DL 10.58.). This declaration by Metrodorus is the earliest known example of a reflexive (uroboric) rejection of knowledge, a type of statement which, as we have seen, is fundamental to both Pyrrhonism and Maadhyamika.
In Metrodorus we find also the emphasis on "acquiescing to the immediate phenomenon" which also is basic to the Skeptic and Buddhist approaches:
One must trust nothing but the bodily sensations (DK 70 Bl.).
Compare the Sutta Nipaata:
No truth exists at all apart from what sense-perception offers (886.).
Aristippus the Socratic was much influenced by Democritus and seems to have influenced Pyrrhon in turn."  Like Democritus he asserted that "things" are assigned qualities merely by convention and are in themselves unknowable (DL 2.92/3), that "only of mental states (pathee, 'sensations', 'phenomena') can we be certain" (ibid.), and that the concept cannot reach the experience:
The affection which takes place in us reveals to us nothing more than itself (Ap. AL 1.190ff.).
We may compare the Buddha's message in the Sabba Sutta (S. 4.15). Aristippus pointed the way back from a concept-based philosophy to experience itself as the "criterion" -- the way which Pyrrhon was to pursue still further.
Anaxarchus, finally, with whom Pyrrhon travelled to India, was either the student of Democritus himself or of Metrodorus or of both, and a contemporary of Aristippus. He is credited by the ancients with extreme success at the tranquil acceptance of phenomena as nondifferent, comparable, indeed, to the more extreme of the Jataka tales:
When Anaxarchus was forced against his will to land in Cyprus [Nicocreon the tyrant] seized him and, putting him in a mortar, ordered him to be pounded to death with iron pestles. But he, making light of the punishment, made that well-known speech, "Pound, pound the pouch containing Anaxarchus; ye pound not Anaxarchus." And when Nicrocreon commanded his tongue to be cut out, they say he bit it off and spat it at him.... For his fortitude and contentment in life he was called the Happy Man (DL 9.59/60.). 
It should be clear that the essentials of primitive Pyrrhonism were already to be found among the followers of Socrates and Democritus by the late-fifth and early-fourth centuries B.C., well before Alexander's expedition to the East. If Pyrrhon encountered such doctrines in India they simply must have reminded him of teachings which had been common in Greece for a hundred and fifty years and which were especially common in his own Democritean lineage.  In fact, it seems that Greek Skepticism derived as much from the Democritean line as from the Eleatic/Socratic, and the question whether Democritus himself may have felt Indian influence -- atomist or skeptic or both -- may be mentioned, but not investigated, here.
Thus the ethical, psychological and language-critical levels of Sextus' work may be said to have been Greek long before Alexander.
2. Did Sextus' dialectic derive from the Greek tradition? I have shown elsewhere some of the earlier stages of this dialectical tradition and, therefore, I will not repeat them here.  The Sextian arguments mentioned in this article, and many others (perhaps all), can be traced back to Eleatic, Sophistic, Academic, Neo-Eleatic or Cynic originals -- all before Alexander's visit to India. We must rule out the possibility of any large-scale dialectical input into Sextus' compendium from outside the Greek tradition; but we cannot rule out the possibility that Pyrrhon brought back some bits or pieces of thought or for-
mulation which seemed useful in terms of attitudes he already held. An obvious candidate is the fourfold negation as preserved by Pyrrhon and Sextus.
3. Was the catu.sko.ti known in Indian philosophy prior to 326 B.C.? The evidence is more ambiguous than is perhaps usually acknowledged. The four alternatives (as Jayatilleke calls them) occur repeatedly in the Paali canon, which does not necessarily predate Alexander in any particular passage."  Further, the Paali canon (D 1.27) seems to associate the four alternatives with a school of Skeptics, possibly that of Sa~njaya, who is one of the six teachers mentioned as contemporaries of the Buddha. If the scheme confidently could be ascribed to Sa~njaya, our question would be answered -- but it is not possible to distinguish the contribution of the Buddhist authors (whom we know to use the catu.sko.ti) from that of the Skeptic being reported on (for whom there is no independent confirmation that he used the catu.sko.ti) `Siilaa^nka, commenting on the Suutrak.rtaa^nga in the ninth century A.D., again seems to associate the catu.sko.ti with different schools of Skeptics supposedly contemporary with the Buddha. But again the passage is ambiguous and the connection cannot be accepted without doubt. Attempts to derive the fourfold logic from the fivefold form attributed to early Skeptic schools, or from the sevenfold logic of the Jains are again interesting but inconclusive. 
4. Could Pyrrhon have derived the fourfold negation from elements in the Greek tradition alone? Again there is ambiguity. Heraclitus had anticipated the third branch by saying that things both are and are not (DK 22A7); Democritus is said to have first formulated the Skeptic slogan "No more this than that" (OP 1.213 and Simpl. Phys. 28.4), and his student Protagoras explicitly denied the principle of contradiction, on the basis of indeterminacy (DL 9.50/1). Dionysodorus' dialectical paean, "Both and neither!" in Plato's Euthydemus anticipates the third and fourth branches of the tetralemma. Plato's Parmenides is a mother lode of such sayings ("both coming to be and ceasing to be and doing neither" [165d], "the nonexistent One both comes to be and ceases to be and also does not come to be or cease to be" [163b], et passim). The aporiai of Eubulides of Miletus, successor of Eucleides of Megara, take direct aim at Aristotle's principle of contradiction and force the interlocutor to answer yes and no to the same questions.
It does, in short, seem possible that Pyrrhon could have devised the four negations out of materials readily at hand in the Greek schools. Above all, the form in which Pyrrhon has cast the four alternatives is strictly Democritean, based on Democritus' "No more this than that":
We should... [say] of each thing that it no more is than is not, than both is and is not, than either is nor is not (Timon, ap. Aristocles.).
Pyrrhon seems to have combined Democritus' description of each thing as 'no more A than not-A' with a Megaric formula of the type used by Plato in the Parmenides ('both A and not-A and neither A nor not-A'). Thus both the
Socratic and Democritean traditions (in both of which Pyrrhon was educated) contributed to the fourfold formula.
In addition to the four alternatives in their Democritean form (as a "fourfold indeterminacy"), Sextus has several occurrences of the four alternatives in the form of logical disjuncta:
The 'something' which they [the Stoics] declare the
highest genus of all is either true or false or neither true nor false or both true and
false (OP 2.86.).
[The highest genus] then is either true or false or at once both true and false or neither true nor false (AL 2.32/3.).
In the doctrine of the Stoics... some [presentations] are probable, some improbable, some at once both probable and improbable, some neither probable nor improbable (AL 1.241/2.).
And of the probable presentations some are true, some false, some both true and false, some neither true nor false (AL 1.243/4.).
All four cases occur in discussions of Stoic thought, and indeed the book Against the Logicians (where three of the four cases occur) is aimed primarily against the Stoics. An earlier scholar stated that "the form of the quadrilemma has nothing to do with Stoic philosophy",  but is probably, I think, in error on that point. Aulus Gellius speaks of a Stoic logical disjunctum which contains three of the four alternatives:
This is of such a sort as "Pleasure is either good or bad or neither good nor bad."... of all the disjuncts, one ought to be true and the others false. But if none of them is true, or all... then that disjunction is false (Noctes Atticae, 16.8.12-24.).
This formula, which lacks the third alternative (both A and not-A), presumably comes from Chrysippus, who "wrote books against 'those who think that a proposition may be both true and false.'"  But the Stoic logic originated two generations before Chrysippus as a continuation of Megarian logic, and Megarian logicians did indeed feature the simultaneous yes and no (as in the conundra of Eubulides). As Mates says, describing, evidently, the pre-Chrysippan phase of Stoic logic, "The classes of true and false presentations are neither mutually exclusive nor mutually exhaustive; some presentations are both true and false and some are neither."  The 'both A and not-A and neither A nor not-A' formulae of Plate's Parmenides seem also to be allusions to this aspect of Megarian (= Neo-Eleatic) thought. 
It is, of course, possible that Indian influence could have intruded somewhere in the long evolution of this formula from Democritus to Pyrrhon. But the point I wish to make is that there is no need to postulate such influence here; skeptical mottoes verging on the fourfold negation had been common in Greece for centuries, in continually changing forms, and there is no difficulty whatever in imagining its occurrence in an early Megarian-Stoic logician whom Pyrrhon, in Democritean fashion, attacked by converting the alternatives to indeterminates, thus casting all the Stoic disjuncts into a limbo between yes and no. On
the principle of economy, the Indian input should be rejected, at least provisionally, as superfluous.
Finally, it is worth noting that as Pyrrhon, following Democritus, denies the possibility of affirming any of the alternatives more than the others, and as Sextus rejects each alternative on its own merits, so the Buddha, in the Paali Nikaayas, is sometimes represented as having "set aside and rejected" all four alternatives (for example, M. 63). As Jayatilleke says, "They also rejected all four alternatives when they considered the question meaningless (that is, a.thapaniiya pa~nha)."  Pyrrhon, by declaring the inapplicability of all four alternatives in every case is, in effect, declaring all questions to be .thapaniiya pa~nha. Among Indian schools associated with the catu.sko.ti, however, Pyrrhon seems closer to the Skeptics than the Buddhists of the Nikaayas, in that he advises suspension of judgment not for the religious purpose of escaping from transmigration, but for the psychological purpose of attaining tranquillity. 
Aside from the catu.sko.ti, Indian influence has been suggested for certain of Sextus' philosophical exempla. 
5. What is the chronological situation of exempla which are common to Pyrrhonism and to Indian thought? We have already seen that both Sextus and Naagaarjuna use the image of wood and fire to exemplify the problem of causation. In addition, both Sextus and various Indian logical traditions use the imagery of smoke and fire to illustrate the process of inference. The image is well known from both Nyaaya and Buddhist logicians. In Sextus we find:
As soon as we see... smoke, we recall... fire (AL
We... infer fire from smoke (AL 2.157.).
They [the Stoics] term a sign 'suggestive' when, being mentally associated with the thing signified, it... suggests to us the thing associated with it, which is not clearly perceived at the moment -- as for instance in the case of smoke and fire (OP 2.100.).
When a man sees smoke, fire is signified (OP 2.102.).
Obviously the image could occur in two contexts by coincidence; nevertheless, the chronology is worth investigating. Sextus seems to derive the image from Stoic sources which probably go back to the third century B.C. Frenkian assumes that the Nyaaya use of the image goes back to the sixth century B.C., but there is really no evidence for this; Bochenski puts the beginning of Nyaaya logic in the last two centuries B.C., that is, after the probable date of Sextus Stoic sources.  The frequency of occurrences, then (if that is really evidence for origin), may favor an Indian origin, but chronology is ambiguous and may even point the other way.
The case is very similar for the imagery of rope and snake. Sextus says:
When a rope is lying coiled up in a dark room, to one who enters hurriedly it presents the simply 'probable' appearance of being a serpent; but to the man who has looked carefully around and has investigated the conditions -- such as its immobility and its color -- it appears as a rope, in accordance with an impression that is probable and tested (OP 1.227 ff.).
The rope-snake analogy is most famous in India from Vedaanta (for example, Gau.dapaada, Maa.n.duukyakaarikaa, 2.17, `Sa^mkara, Maa.n.duukyakaarikaabhaa.sya, passim), but Verdu calls it also "a classical illustration used since antiquity in Buddhism," "the simile of the fool who sees a rope in the dusk and thinks it to be a snake. A wise man appears and teaches him that he has nothing to fear, for the snake is a mere illusion created by a simple rope."  This "popular simile" is found in specifically Maadhyamika contexts in AAryadeva's Cittavi`suddhiprakara.na and in Candrakiirti. 
Sextus seems to have derived the image from Carneades, who did not himself write but whose views were written up by his student Cleitomachus. A closely related image appears in Demetrius, De Elocutione (159):
Relief from fear provides an occasion for wit, as when a man has been afraid without reason, mistaking a strap for a snake, or a pot for a hole in the ground. 
The De Elocutione has been dated by Grube to circa 270 B.C., and by others as late as the first century A.D.  As with the smoke-fire image, the frequency with which it occurs in Indian literature and its rarity in Greek literature (where the standard image for this purpose is Leucippus' oar-thrust-in-the-water) have led scholars to assume that the image is Indian in origin. But I am not aware of any Indian examples earlier than Dignaaga in the fifth century A.D.,  and the related instance in Demetrius may be as much as eight centuries earlier. It is then clearly a possibility that the image diffused from Greece into India, perhaps by way of Cleitomachus' book. The fact that Sextus, or his source (Cleitomachus?), seems to have improved on Demetrius' form of the image suggests that it evolved in Greece, whereas in India it appears in a single static form possibly derived from the mature form in the Greek tradition. The question must be left open at present, but I hope to have shown that the priority of India in use of this image is by no means certain.
A final case is the formulaic series of negations with which Timon summarizes Pyrrhonism. These compare interestingly with Buddhist formulations such as MK 18.11 and Candrakiirti's eight negations, but are also in the tradition of Greek apatheia, athambia, adiaphoria, ataraxia, and so forth, all earlier than 326 B.C.
Finally the evidence is insufficient either to posit or deny influence either from India to Greece or from Greece to India in these cases. I hope to have shown that there is nothing whatever in Pyrrhonism which requires the hypothesis of foreign input -- but certainly Pyrrhon was in India and did speak with Indian yogis and/or philosophers. The lack of demonstrable input should impress us with how similar the two traditions were: they could interact without producing strangeness -- at least on the Greek side.
The other possibility -- that the Maadhyamika dialectic somehow "came from" Greece -- has never been seriously considered, yet there is a certain amount to be said for it. To begin with, Naagaarjuna's argumentation appears
to involve "the basic ways of reasoning found in the West."  Like Sextus' book, it is a compound of empiricism and logic, with no use of mystical or traditional religious arguments. Furthermore, although the basic purpose of pacifying prapa~nca may be found in the Praj~naapaaramitaa texts and the Sutta Nipaata (which may or may not predate Alexander), there seems to be inadequate background in India for its dialectical methods.
6. Were there Indian dialectical systems predating Naagaarjuna? There is reason to believe that some Materialists and Skeptics in the age of the Pali Nikaayas were protodialectical -- but their mode of refutation seems to have been by very primitive implied modus tollens,  not by dichotomy and dilemma, and there is no sign of regressus ad infinitum or the critique of relatives. The Materialist work Tattvopaplavasi.mha of the 7th century A.D. does employ dichotomy and dilemma,  but only centuries after the Maadhyamika had used it, and, as Jayatilleke a says, the argumentation characteristic of that work is "far too sophisticated to have its roots in the period of Early Buddhism."  The summary of materialism in the Sarvadar`sanasa^mgraha (14th century A.D.) employs infinite regress,  but there is no justification for reading it back to the earliest phase of the school, which is more likely represented by the simple verses at the end of the summary.
Nevertheless, two powerful dialectical positions were foreshadowed in these schools. According to `Siilaa^nka, early Skeptics denied dogmas on the ground that dogmatists disagreed with one another on every point,  a view which Murti attributes to the Buddha, which we have seen in Sextus, and which Sextus derived from Arcesilas of Tarentum, of whom Diogenes Laertius says: "He was the first to suspend judgment owing to the contradictions of opposing arguments" (DL 4.28.).
Closely related is Sa~njaya's claim that the dogmatists simply believed what they liked, namely, followed their personal preferences and then attempted to rationalize them (a critique which Bertrand Russell made much of for the same purpose).  These arguments, unsupported by more than the simplest beginnings of critical method, I call protodialectical. Further, Sa~njaya's criticism of the subjectivism of the dogmatic schools clearly implies that they were not offering much logical support for their positions -- in other words, that Indian philosophy as a whole was in his time still largely prelogical and predialectical. It seems that, as Bochenski said, "we can put the beginning of systematic thought in India in the last centuries B.C."  The Nyaaya logic may have grown up in part in response to the early protodialectical critique, and may in turn have stimulated the further development of Caarvaaka dialectic at a time (circa 100 B.C.) when it might have fed into the beginnings of the Maadhyamika school. These matters are all, of course, very obscure, and the positions I am recommending are based on argumenta ad silentium and hence less than certain; a change in the state of the evidence could indicate a total revision of them. Nevertheless, they seem the best presently available in terms of the evidence, and they apply to our subject in two ways.
First, not only could the Pyrrhonist dialectic have derived perfectly well from the Greek tradition, but also it seems that it could not have derived from any Indian tradition likely to have been in existence in 326 B.C.  Secondly, Naagaarjuna's work appears without known Indian forerunners of its dialectical methods. It has the whole pattern of the Greek dialectic, with its complex and extensive system of arguments which in Greece took six centuries to develop, yet it arises without evidence of developmental stages in its own tradition -- and this is a situation which, in the history of cultural changes in general, causes scholars to look at the possibilities of foreign input.
Naagaarjuna seems to have lived in the second or third centuries A.D. and thus was roughly a contemporary of Sextus Empiricus. But virtually all of Sextus's arguments were collected by him from earlier Greek dialecticians, who had been working steadily at the critical dialectic since the time of Parmenides. The main body of arguments seems to have been systematized at least by the time of Aenesidemus in the last century B.C. Aenesidemus, in fact, seems to have been the great Pyrrhonist dialectician, and Sextus his redactor. It is commonly assumed by Buddhologists that Naagaarjuna, like Sextus, was the culmination of a long tradition; but there is really no evidence for that tradition, not in dialectic anyway. And the fact that there is at hand an almost identical Greek dialectic which is all in place two or more centuries before Naagaarjuna, much of its technique and argumentation being a full seven centuries earlier, would lead an historian to look around for channels of diffusion.
7. Could the Greek dialectic have entered India before or during Naagaarjuna's lifetime? One channel would pass through the Hellenized areas of northwest India and neighboring Bactria, areas which purveyed Hellenistic cultural influence from the time of Alexander to that of Kanishka -- that is, during the presumed formative period of both the Praj~naapaaramitaa and the Maadhyamika. The Hellenistic Greeks were passionately interested in the religions and philosophies of other cultures, and the Mediterranean mystery cults show how ready they were to participate in them. There is ample evidence that in India they penetrated deeply into Buddhism and brought their peculiarly Greek talents to the service of the Dharma. We need only recall the A`sokan edicts issued in good literary Greek, the sub-Platonic discourse of the Milindapa~nha, the elevation of King Menander to the status of arhat, the Buddhist caves at Karle and Nasik endowed by wealthy Greeks; this remarkable fusion of cultures may be symbolized by the Corinthian capitals where buddhas sit meditating among acanthus leaves and by the Kanishkan coin with the name Buddha written in Greek characters.
The central question about the Indo-Greeks as diffusion channels for dialectical philosophy is whether Sir William Tarn was correct in calling them a Hellenistic dynasty and in claiming that their cities preserved the polis culture.  Within a self-consciously Hellenistic dynasty, or within a genuine polis, there would have been philosophy teachers as surely as stonecutters and fluteplayers.
If, for example, it were archeologically established that the Graeco-Bactrian and Indo-Greek cities had Greek theaters, then we could presume with high probability that they had philosophy schools too -- this in or near a city like Taxila! -- and that cross-fertilization almost certainly took place between the two traditions.
In fact, recent archeological work at Kandahar, Ai' Khanoum, Charsada and Taxila has gone a long way toward establishing Tarn's view against the negative of, for example, Narain.  These sites have yielded the rectalinear plans of unmistakably Hellenistic cities far beyond the scope of mere garrison towns. At Ai' Khanoum "a semicircular hollow has been suspected of marking the position of the theatre."  Charsada-Shaikhan had a large stuupa in the middle of a Hellenistic town. Kandahar has yielded A`sokan edicts published in Greek for Greeks. Throughout these sites the impression is of a full and integrated Hellenism (or polis culture), in more or less continuous touch (on epigraphical and art historical evidence) with the Mediterranean, and yet sensitively open to Indian thought, especially Buddhism. Mortimer Wheeler says of Kandahar, "It was a balanced Greek city with its writers, its philosophers, its teachers"; and of Ai' Khanoum, "from the overall Hellenism of the scene... Greek priests, philosophers, craftsmen may already be inferred."  Judging from what is known of Hellenistic towns in the ancient Near East, such provincial philosophy schools would have a primary orientation toward either Stoicism, Epicureanism, or the Megarian, Academic, and Skeptic dialectic. Each teacher taught from a selection of books in his own lineage; among those which could be found in such a setting in the last three centuries B.C. are the works of Chrysippus, Epicurus, Eubulides, Diodorus Cronus, Menippus, Cleitomachus, Timon, Aenesidemus, and others.
Of course, northwest India, the area so deeply penetrated by Greek civilization that Wheeler now calls it "Indo-Graecia" (compare "Magna Graecia" for Sicily and South Italy), has been prominently mentioned as the area in which the Praj~naapaaramitaa developed.  Conze suspects Greek influence on the Praj~naapaaramitaa, and Kalupahana calls the Praj~naapaaramitaa "the origin of dialectical consciousness in India."  The matter awaits further clarification through archeology, but scholars should be aware that typology, chronology, and geography are all in line for possible Greek input into both the Praj~naapaaramitaa and the Maadhyamika, and that the current trend of the evidence is to make such input increasingly likely.
The other great diffusion channel is through the Graeco-Roman trading centers of the Southeast. These settlements were in some cases permanent towns, colonies really, like Arikamedu near Pondicherry, built or rebuilt in the Roman fashion and equipped, in one case at least (Muziris), with an official templum Augusti, indicating the presence of a Roman imperial official.  The amount of traffic between these towns and the Mediterranean was simply enormous; Strabo records (2.5.112) that around 14 A.D. two hundred and twenty ships yearly
set sail from Myos Hormos (one of the two Red Sea ports of Alexandria) for India. This trade continued at high volume, from both Red Sea ports, till about 200 A.D., suggesting literally tens of thousands of such voyages. All the ships' captains' names which are extant are Greek, and for the Greeks, among whom interest in philosophy was all but pandemic, any occasion could involve the discussion of ideas or the copying of books. The point is that between Plato's Parmenides and Sextus' Outlines of Pyrrhonism there were scores of Greek dialectical books, no longer extant, any one of which could have made its way to India during or shortly before the time of Naagaarjuna. The fact that no Indian text mentions this is not very important, since no Indian text certainly mentions Alexander the Great either, though he surely was there and probably had a major influence on the development of the Mauryan empire. 
The points of contact in this area are many. The area of Amaraavati, where Conze feels that the Praj~naapaaramitaa originated and developed into the Maadhyamika,  shows clear signs of Graeco-Roman influence in the early centuries A.D., though the main Graeco-Roman area awaits excavation still. At nearby Naagaarjunakonda, where Naagaarjuna is traditionally supposed to have spent most of his life, Graeco-Roman medallions have been found, at a Buddhist stuupa, from the second century, the age of Naagaarjuna himself.  We may be certain that here, as in the Northwest, there were Greeks who knew Indian languages and Indians who knew Greek. Much circumstantial evidence suggests Stoic influence on Tamil literature, and at the same period some Sanskrit books made their way in Greek translation to the Mediterranean.  Most impressive of all is the evidence for diffusion of Greek astronomical texts from the Mediterranean to India. It has long been recognized that such diffusion took place in the fifth century A.D., and one Indian text, the Gaargi Sa^mhitaa, explicitly acknowledges it:
The Yavanas are barbarians, yet the science of astronomy originated with them and for this they should be reverenced as gods. 
But it has recently been shown that in 149-50 A.D., shortly before or during the lifetime of Naagaarjuna, a Greek astrological book "was directly transmitted... from Roman Egypt to Western India."  Its translators, says Pingree, were "Lords of the Greeks, that is to say, men exercising some sort of authority over Greeks settled in the domains of the Western K.satrapas."  These Greeks "appear to have had some sort of political organization within the state," enjoying "extraordinary privileges" and "superior station."  Assuming the accuracy of this description, we may agree that "doubtless there were many other lines of transmission running in both directions between the two cultures,"  and, of course, dialectical as well as astrological works may have been transmitted. We know that an appetite for Greek philosophy had existed in India for centuries: the Indian "sophists" at Taxila questioned Onesicritus
about Greek philosophy (Strabo 15.1.65), and Bindusara specially requested a Greek philosopher from Antiochus I (Ath. 14.652f-653a).
This brief selection of data must suffice for now.  It is obviously very suggestive that the areas where Mahaayaana Buddhism is most commonly supposed to have arisen -- Gandhaara, Kashmir, and Amaraavati -- are the areas where Greek culture penetrated most deeply. But, however suggestive the evidence is, our conclusions on the historical questions must remain, for the time being, aporetic. It seems that cross-fertilization of dialectical techniques, arguments, and exempla may have taken place in both directions. Apparent gaps in the Indian tradition as it is presently known leave more room there than in Greece for the intrusion of foreign influence, and the general trend of Greek and Roman penetration into India provides clear and abundant mechanisms for diffusion. Beyond that, nothing really definite can be said until the appearance of new evidence or of new insights into the existing evidence. It is hoped that by opening the question this article may stimulate those insights from others. 
1. For the Megarians and their relationship to Buddhist thought see Thomas McEvilley, "Early Greek Philosophy and Maadhyamika," Philosophy East and West 31, no. 2 (April, 1981): 141-164.
2. This article will deal only with Pyrrhonic Skepticism and not with the Academic Skeptics Arcesilas and Carneades. The two groups shared certain dialectical tropes, but otherwise, as Burnet puts it, "were separated... toto caelo" (ERE s.v. 'Sceptics').
3. All quotations from Diogenes Laertius are translated as in R. D. Hicks's Loeb edition, 2 vols. (Cambridge [Mass.] and London, 1925).
4. A brief summary is preserved ap. Aristocles; see H. Diels, ed., Poetarum Philosophorum Fragmenta, fasc. 3, pt. l of Wilamowitz, ed., Poetarum Graecorum Fragmenta (Berlin, 1901) , pp. 175-176. For an English translation, see Burnet in ERE under 'Sceptics'.
5. I will quote the Maadhyamikakaarikaas in the translation of Kenneth K. Inada, Naagaarjuna: A Translation of His Muulamadhyamikakaarikaa (Tokyo: Hokuseido Press, 1970); the Vigrahavyaavartanii in the version of Frederick J. Streng, Emptiness: A Study in Religious Meaning (Nashville, 1967), pp. 221-227; and Sextus in the Loeb translation of R. G. Bury (4 vols., Cambridge, [Mass.] and London, 1933-49), with occasional slight changes which do not depart from literalness. Henceafter OP refers to Outlines of Pyrrhonism, AL refers to Against the Logicians, APh refers to Against the Physicists, AE refers to Against the Ethicists, AP refers to Against the Professors.
6. Charlotte L. Stough, Greek Skepticism (Berkeley, 1969), p. 80.
7. AAryadeva, `Sata`saastra, in G. Tucci, Pre-Di^nnaaga Buddhist Texts on Logic from Chinese Sources (Baroda, 1929), p. 82.
8. See G. C. C. Chang, Teachings of Tibetan Yoga (New Hyde Park [NY], 1963), p. 34.
9. In Sems-nyid rang-grol (The Natural Freedom of Mind), trans. H. V. Guenther in Crystal Mirror IV (Berkeley: Dharma Publishing Company, 1975), p. 117.
10. Wing-tsit Chan, A Sourcebook in Chinese Philosophy (Princeton, N.J.: Princeton University Press 1963), p. 356. With this statement Seng Chao sums up the Maadhyamika-kaarikaas of Naagarjuna.
11. See note 4 herein.
12. See Chan, op. cit., p. 367.
13. Trans., in John Blofeld, The Zen Teaching of Hui Hai (NY: Samuel Weiser, 1972), p. 51
14. Streng, op. cit., p. 87.
15. See Richard H. Robinson, Early Maadhyamika in India and China (Delhi, 1976), p. 42.
16. See McEvilley, "Early Greek Philosophy and Maadhyamika," (above n. 2), and Richard Hubert Jones, "The Nature and Function of Naagaarjuna's Arguments," Philosophy East and West 28 (1978): 490-491.
17. Jones, ibid., pp. 488-489. For Sextus see, for example, APh 1.242.
18. A much fuller passage by passage comparison will be found in my book (in preparation) on Greek and Indian philosophy.
Compare `Saantideva on the subject of contact:
If there is an interval between the sense and its object, how is there a contact between them? If there is not interval, they are a unity; and how then is there a contact? There is no entering into an atom by an atom; it is equal (to the other atom) and without free space. Without entering there is no mingling, there is no contact (BCA 9.94-5.).
Translated in Marion L. Matics, Entering the Path of Enlightenment (NY: MacMillan, 1970) p. 220. All quotations from `Saantideva will follow this translation.
If there is no father without a son, what is the origin of the son? If there is no son, the father does not exist. Thus the nonreality of both of them (BCA 9.114.).
21. Robinson, op. cit., p. 50.
22. See McEvilley, "Early Greek Philosophy and Maadhyamika."
23. Compare A. J. Ayer: "If the validity of every proof had to be proved in its turn, we should fall into an infinite regress." The Problem of Knowledge (NY: Penguin, 1977), p. 43.
24. Edward Conze, Buddhist Thought in India (London: Allen and Unwin, 1962), p. 240.
25. T. R. V. Murti, The Central Philosophy of Buddhism (London: Allen and Unwin, 1974) , pp. 138-139.
26. Chan, op. cit., pp. 354-355.
27. Murti, op. cit., p. 137.
28. D. T. Suzuki, "Existentialism, Pragmatism and Zen," in Zen Buddhism, ed. W. Barrett (NY: Anchor Books, 1956), p. 269. See also Jones, op. cit., pp. 491-492.
29. Cited by David J. Kalupahana, Buddhist Philosophy, A Historical Analysis (Honolulu Hawaii: The University Press of Hawaii, 1976), p. 138.
30. John Blofeld, trans., The Zen Teaching of Huang Po (NY: Grove Press, 1958), p. 130.
31. Jones, op. cit., p. 491.
32. For this term see John Visvader, "The Use of Paradox in Uroboric Philosophies," Philosophy East and West 28 (October, 1978): pp. 455-467.
33. Trans., in Conze, Large Sutra on Perfect Wisdom (Berkeley, 1975), p. 144, n. 4.
34. Streng, op. cit., p. 97.
35. It is worth comparing the attitude toward "wrangling" which is expressed in the Sutta Nipaata (for example, IV. 3, 5, 8, 9, 11) and by Hui Neng:"We do not quarrel even in the midst of a hostile crowd." (A. F. Price and Wong Mou-lam, The Diamond Sutra and the Sutra of Hui Neng [Berkeley, Shambhala, 1969]), bk. 2, p. 41.
36. Prasannapadaa 12.
37. The Spiritual Teachings of Ramana Maharshi (Berkeley: Shambhala, 1972), p. 6; and compare Murti, op. cit., p. 353.
38. Ludwig Wittgenstein, Tractatus Logico-Philosophicus (London, 1922), p. 189.
39. Murti, op. cit., pp. 124ff
40. See Th. Stcherbatsky, The Buddhist Conception of Nirvaa.na (Leningrad, 1927), pp. 187-188.
41. G. Tucci, trans., "The Ratnaavalii of Naagaarjuna," JRAS (1934): 307-325; (1936): 237-252, 423-435.
42. A. K. Gangadean, "Formal Ontology and the Dialectical Transformation of Consciousness," Philosophy East and West 29, no. 1 (January, 1979): 22.
43. Translated as in Conze, Buddhist Wisdom Books (London: Alien and Unwin, 1958), p. 93.
44. (1) That Pyrrhonic Skepticism is essentially methodological and has the aim of making
philosophical inquiry more scientific (Charlotte Stough, op. cit., p. 104); (2) that the Skeptic must "be engaged in a continuing (and perpetually unresolved) search for a definitive answer to each and every philosophical question... will amass a large stock of philosophical arguments... [and his] quietude... begins to resemble the peace of the well-armed man always on guard and ready for combat" (Dick Garner, "Skepticism, Ordinary Language, and Zen Buddhism," Philosophy East and West 27, no. 2 : 167); (3) that Sextus' quietude applies only to philosophical questions and would have no effect on everyday life (ibid, p. 168); (4) that "the most important effect of the Sceptic's epoche (suspension) is to preserve him from philosophical discussion" (Arne Naess, Scepticism [NY, 1968], p. 4); (5) that the Skeptic, "once all judgments are withdrawn," will not "be disturbed by... vexation about the future, and thus [will be] able to enjoy the present" -- but that this condition "bears on no higher level of illumination or understanding of truth" (Chung-ying Cheng, "Nature and Function of Skepticism in Chinese Philosophy," Philosophy East and West 27, no. 2 : 138-139). Others could be mentioned. M. Burnyeat's treatment would be the most acceptable except for his remarkable (and unargued) conclusion that (in Buddhist terms) the realization of anatta through mindfulness practice is either impossible or inhuman ("not, after all, a possible life for a man"). See "Can the Sceptic Live His Scepticism," in M. Schofield et al. edd., Doubt and Dogmatism: Studies in Hellenistic Epistemology (Oxford, 1980), p. 53.
45. It seems that the interpretations listed in the previous note are not based on what Sextus himself said. (1) Sextus says nothing about seeking the truth or improving the methods for seeking truth; he could not be more misrepresented. (2) Evidently results from interpreting a single Sextian passage out of context of Sextus' whole thought:
Some have claimed to have discovered the truth, others have asserted that it cannot be apprehended, while others again go on inquiring. Those who believe they have discovered it are the Dogmatists... the Academics treat it as inapprehensible; the Skeptics keep on inquiring (OP 1.2.).
In context this certainly cannot mean that the Skeptic "is engaged in a continuing... search for a definitive answer." It means that the Skeptic asserts no position at all, in contrast to the Dogmatist, who asserts Yes to the question of knowledge, and the Academic, who (just as dogmatically) asserts No. The statement about amassing arguments is based on a misunderstanding of Sextus' role: like Candrakiirti, he regarded the dialectic as a medicine to cure minds diseased by opinions; as a practising Skeptic doctor he collected many medicines for use when appropriate -- there is no question of 'seeking definitive answers'. The Buddha himself is regarded in most Buddhist schools as just such a doctor, dispensing different arguments to different patients as they needed them; for example:
The mystery of the Tathagatas etc. is difficult to understand, Sariputra, because when they explain the laws... they do so by means of skilfulness, by the display of knowledge, by arguments, reasons, fundamental ideas, interpretations and suggestions. By a variety of skilfulness they are able to release creatures that are attached to one view or another. (Saddharmapundarika Suutra, 2, trans. in H. Kern, Saddharma-pundarika or the Lotus of the True Law, Sacred Books of the East, no. 21 (NY, 1963 ), pp. 30-31).
Other passages to the same effect include: A^nguttara Nikaaya I.10; Naagaarjuna, Jewelled Garland; Candrakiirti, Pras. 18.11 (de Jong, Cing chapitres de la Prasannapadaa [Paris, 1949], pp. 15ff.); Abhidharmako`sa-kaarikaa, v. 22 (cited Murti, op. cit., p. 42); Seng Chao (in Chan, pp. 347-348), and Chi-tsang (ibid., p. 336). (3) That Sextus is "curing" only philosophical opinions and not opinions about everyday life shows inattention to Sextus' own words: to be freed from the conviction that one's present afflictions -- cold, hunger, pain, and so forth -- are evils to be escaped from is indeed a radical alteration of everyday life. (4) Sextus does not say that the main effect of the dialectic is to free one from philosophical questions; he says that the Skeptic with suspended mind is freed from the passions of pursuit and avoidance in all areas of activity -- and it would be hard to imagine a more thoroughgoing change in human life. (5) Sextus also does not say that it is only "vexation about the future" which the suspended mind is freed from, but vexation about the present and the past, too; that the state of ataraxia "bears on no higher state of illumination" is not the least clear: many Zen texts, with their emphasis on "ordinary everyday mind" as the goal could be interpreted the same way; indeed the condition of being able to enjoy the present
without vexation about the future is the state which Hui Hai and many other Buddhist masters call the Buddha-state: the ability to relate nonconceptually to the present moment is a "higher state of illumination"; that this state does not bear on any "higher understanding of truth" again seems a misfire: the Maadhyamika and Skeptic practitioner take a stand above the truth-untruth dichotomy, and this in itself constitutes a "higher understanding of truth."
46. Conze, Buddhist Thought in India, pp. 242-243.
47. Gangadean, op. cit., p. 38.
48. Ibid., p. 37.
49. Jean-Paul Dumont, Le Scepticisme et le Ph'enome'ene (Paris, 1972), pp. 212, 215.
50. For example, The Zen Teaching of Hui Hai, pp. 95-96.
51. Conze, Buddhist Thought in India, p. 242.
52. Bernard Tetsugen Glassman, in On Zen Practice, I., edd. H. T. Maezumi and B. T. Glassman (Los Angeles: Zen Center of Los Angeles, 1975), p. 11.
53. Trans. H. L. Jones, The Geography of Strabo, vol. 7 (London/ NY, 1930) Loeb Classical Library, p. 101.
54. E. G., V. Brochard, Les Sceptiques Grec (Paris, 1887), pp. 73, ff.; B. M. Barua, Prolegomena to a History of Buddhist Philosophy (Calcutta, 1918), p. 6; M. Patrick, The Greek Skeptics (NY, 1929), p. 57; L. Robin, Pyrrhon et le skepticisme grec (Paris, 1944), pp. 6, 8; E. Conze, Buddhism (NY, 1959), pp. 140-3; G. Woodcock, The Greeks in India (London, 1966), p. 27, C. J. deVogel, Philosophia I (Assen, 1970), p. 428.
55. ERE, s. v. "Sceptics."
56. Trans., in E. Conze, ed., Buddhist Texts through the Ages (NY: Harper, 1964), p. 163.
57. Robin, op. cit., p. 6.
58. See Dumont, op. cit., pp. 212-215, for a good discussion of Democritean phenomenalism and its influence on Pyrrhon.
59. K. Mizuno, Primitive Buddhism (Ube City, 1969), p. 84.
60. See, for example, Dumont, op. cit., pp. 229-232.
61. It is worth noting that the story about the tongue is told also of Zeno of Elea, demonstrating the continuity of this Democritean ethic with that of the Eleatic dialecticians.
62. Strabo, in fact, records (loc. cit.) that Onesicritus compared the yogis' teachings to those of Socrates and Diogenes.
63. McEvilley, "Early Greek Philosophy and Maadhyamika."
64. See E. Conze, Thirty Years of Buddhist Studies (Oxford: Cassirer, 1967), pp. 4-10.
65. Jayatilleke, Early Buddhist Theory of Knowledge (London, 1963), pp. 121, 134ff., 336-8.
66. A. M. Frenkian, "Sextus Empiricus and Indian Logic," PQ (India) 30, no. 2 (1957): 123.
67. Benson Mates, Stoic Logic (Berkeley, California: University of California Publications in Philosophy, 1953), p. 84.
68. Ibid., p. 34.
69. See A. E. Taylor, Plato, the Man and His Work (London, 1960 ), pp. 350/1, 369/70.
70. Op. cit., pp. 293, 344-345.
71. See ibid., pp. 127, 130.
72. Frenkian, op. cit.
73. I. M. Bochenski, A History of Formal Logic (Notre Dame, 1961), p. 416. See Frenkian, op. cit. Frenkian's argument suffers greatly from inattention to chronological problems, as does its revival by E. Flintoff ("Pyrrho and India," Phronesis 25 : 88-108).
74. Alfonzo Verdu, Dialectical Aspects in Buddhist Thought (Lawrence, Kansas: University of Kansas, 1974), pp. 27-28.
75. AAryadeva cited by S. B. Dasgupta, Introduction to Tantric Buddhism (Berkeley, 1974), p. 40, Candrakiirti by Th. Stcherbatsky, op. cit., pp. 187-188.
76. Trans., in G. M. A. Grube, A Greek Critic: Demetrius On Style (Toronto, 1961), p. 98.
77. Ibid., p. v, and D. M. Schenkeveld, Studies in Demetrius On Style (Amsterdam, 1964), p. 147.
78. Pramaa.na-samuccaya, 1;cited by Frenkian, op. cit.
79. Jones, op. cit., pp. 485-486.
80. See, for example, Jayatilleke, op. cit., pp. 103/4.
81. See, for example, S. Radhakrishnan and C. Moore, edd., A Sourcebook in Indian Philosophy (Princeton, New Jersey: Princeton University Press, 1957), p. 239, and Jayatilleke, op. cit., pp. 83-84.
82. Op. cit., p. 76.
83. Radhakrishnan and Moore, op. cit., p. 231.
84. See Jayatilleke, op. cit., p. 112-114.
85. B. Russell, Our Knowledge of the External World (NY: Norton, 1929), p. 29.
86. Bochenski, loc. cit.
87. Conze argues that since Pyrrhonism obviously derived from India, then the Maadhyamika must have existed as early as the fourth century B.C. His error (shared by Robin, Frenkian, and others) is in failing to see the obvious Greek forerunners of Pyrrhon. See Buddhism, p. 142.
88. W. W. Tarn, The Greeks in Bactria and India (Cambridge, 1951).
89. A. K. Narain, The Indo-Greeks (Oxford, 1957).
90. Mortimer Wheeler, Flames Over Persepolis (NY, 1968), p. 79. This book contains a convenient summary, with bibliography, of the archeological work discussed here.
91. Ibid., pp. 68, 84.
92. E. Lamotte, "Sur la formation du Mahaayaana," Asiatica (1954).
93. Conze, The Praj~naapaaramitaa Literature ('S-Gravenhage, 1960), p. 10; Kalupahana, op. cit., p. 129. Note the parallelism between Kalupahana's statement that Praj~naapaaramitaa literature pointed out "the conflict between noumenal reality and phenomenality" (ibid) and Sextus' remark that the Skeptic "opposes appearances to judgments" (OP 1.8).
94. Mortimer Wheeler, Rome Beyond the Imperial Frontiers (London, 1954), p. 121.
95. See Sylvain Levi, "Alexander and Alexandria in Indian Literature," IHQ 12(1936): 121-133.
96. The Praj~naapaaramitaa Literature, pp. 9-11.
97. Wheeler, Rome Beyond the Imperial Frontiers, pp. 152-153.
98. X. S. Thani-Nayagam, "Indian Thought and Roman Stoicism," Tamil Culture 10 (1963): 1-36; E. H. Johnston, "Two Notes on Ptolemy's Geography of India," JRAS (1941): 208-222: "An identifiable Sanskrit text [was] available in some form or other at Alexandria" (p. 222), a Puranic text which served as one of Ptolemy's sources in the second century A.D.
99. Quoted by H. G. Rawlinson, Intercourse between India and the Western World (Cambridge, 1926), p. 173. Compare Otto Neugebauer, The Exact Sciences In Antiquity (Providence, 1957), p. 7.
100. See David Pingree, The Yavanajataka of Sphujidhvaja, 2 vols. (Cambridge [Mass.], 1978), p.v.
101. Ibid., p. 3.
102. Ibid., p. 4.
103. Ibid., p. 3.
104. A full presentation of the evidence for diffusion will be found in my forthcoming book.
105. Due to limitations of space a number of remarkable parallels between Pyrrhonism and Maadhyamika thought have not been mentioned here -- including the doctrine of two truths, the use of apparent contradictions (based on a mixing of the two truths) as teaching devices, and the admission of empirical evidence into the dialectic (for examples, MK 13.3, 7.21, 7.24, 21.8; APh 1.241-3 et passim) -- , but will be included in the fuller treatment mentioned in note 18 herein.