Swords and diamonds—Thich Nhat Hanh on the law of identity

The Diamond Sutra is one of the earliest and most treasured of the Perfection of Wisdom Sutras and had a wide influence on the development of Zen Buddhism. There has been, in recent years, great interest in one particular form of sentences that repeatedly occur in the sutra, sentences of the form “A is not A, therefore it is A”. These sentences display what has been called the “logic of not” or the “logic of affirmation-in-negation”. They are of special interest since they do not only encapsulate one of the central insights of Zen Buddhism, that of nonduality, but at the same time seem to go against one of the most orthodox laws of logic in Western philosophy, the law of identity. This paper discusses the interpretation of these “diamond sentences” by the Vietnamese Zen monk Thich Nhat Hanh. I present Thich Nhat Hanh’s interpretation of the diamond sentences in terms of interbeing and go on to argue that and explain how, on his interpretation, the validity of the law of identity is indeed rejected. Finally, I spell out consequences for formulating a “logic of Zen” and for a related debate about the validity of the law of non-contradiction in Zen.