Buddhist logic and Nagarjuna

Graham Priest promotes a wildly incorrect view of Buddhist logic and teachings. He believes that Buddhist doctrine contains contradictions, which is utter nonsense. His problem is that he does not properly understand Aristotle's logic so cannot understand Nagarjuna. Not being a Buddhist, Priest has no grasp of the Two Truths doctrine and seems to believe it leads to contradictions, which is such a complete misunderstanding it seems almost wilful.

Let's examine the question here.

..."Western/Aristotelian logic doesn't tolerate contradictions (principle of non-contradiction)..."

True.

..."and everything has to be either true or false (principle of the excluded middle),

This is wrong. The principle of bivalence is what you're thinking of and this is not necessary for dialectical logic. This logic works with statements that are true or false (in the form A/not-A) but it does not say that all statements must be true or false. The LEM is applicable where a pair of statements meet Aristotle's specification, (which is that one is true and one false), but statements do not have meet this specification. Where they do not the law does not apply. This is the point that Priest misunderstands, and it is why Buddhist doctrine contains no contradictions.

..." but Buddhist logic follows a system called the catuskoti which implies that statements can be true, false, true and false, or neither true nor false."

This is an utterly ridiculous idea. I can't imagine how anyone could arrive at it. Buddhist logic is no different from Aristotle's, it's just that it is applied to pairs of statements on two axes (this or that, neither or both). Priest muddles the issues and creates complications where none are necessary. He does Buddhism a massive disservice, as is shown by the low view you have formed of Buddhist logic after reading him. He seems to believe that Buddhists are idiots.

I would suggest that Priest is ignored. Nagarjuna offers us a rigorous application of Aristotelian logic and if it were not rigorous the whole argument in Fundamental Wisdom would fall apart.

For a longer response I have an essay on Bernardo Kastrup's blog entitled, 'Aristotle, Nagarjuna and the Law of Non-Contradiction in Buddhist Philosophy'. https://www.bernardokastrup.com/2017/05/aristotle-nagarjuna-and-law-of-non.html

This puts paid to Priest's anti-Buddhist ideas. He should take the trouble to study Buddhism.

There are NO dialectical or 'true' contradictions in Buddhist doctrine and this is exactly what Nagarjuna proves.

I would like to comment on a few points:

There are hundres of places in the suttas where the Buddha said that something was wrong or didn't make any sense, it is not that "anything goes", not at all, sometimes he did that using examples, a nice one was when the Buddha came across a trible, in this trible when someone dies, they used to turn the person facing the skies and call his name, screaming, they believed this way the person would see Heaven and go up there, the Buddha said: "Suppose I throw a stone in a river and scream "come to the surface!" will it come? In the same way the person you go up and down according to kamma, not because someone is calling him"

Buddhism may not be so imperative or black and white as other religions, take the precepts for example, Buddha said we should refrain from doing A, because the consequence B will lead you to suffering, in other religions you will probably read: you shall not do that, end of story. I'm noy saying buddhism is better or worse, just different.

Finally, Nagarjuna was a great buddhist, but his texts have different weight in different traditions, meaning we all deeply respect him and Milarepa for example, but the level of devotion changes.

Originally the Catuṣkoṭi or Tetralemma was just an indication of all possible combinations of two predicates, and obviously, if these two predicates don't contradict, there is no problem.

Now, the Buddha himself does make seemingly contradictory statements, like when he refuses to answer the questions of Vacchagotta in SN 44.10, who asks first whether there is a self, then whether there is no self. Questioned by Ananda as to why he did not answer, the Buddha effectively claims, that both answers would have been wrong.

In this case, since there is only one predicate (and its contradiction), there do arise logical problems. The only attempt, to solve these kinds of problems I am aware of is in the article

Klaus Butzenberger: Einige Aspekte zur catuskoti unter besonderer Berücksichtigung Nagarjunas, in: Synthesis Philosophica 1990, 567–580.

If you know German, then go read it. If not, let me summarize that it attempts to solve these problems in three ways: by classical logic, non-classical logic and thirdly by admitting its insolubility, but Butzenberger admits, that each of these attempts at solution does remain unconvincing to fruitless.

This might - now here comes my 50 cents - be due to the case, that the Tetralemma is used by a great number of authors in Indian logic and they do not handle it the same way. In the case of the Buddha's refusal to answer, it might be conjectured, that the Buddha is talking in two different levels of truth: a conventional truth and an absolute truth. So in order to remain truthful on the absolute level, we may have to accept contradictions on the conventional level, if - what the Buddha sometimes blames questioners for - the question is posed in a wrong way.