To the question, “What is self-consciousness?” the answer given is, “Consciousness of oneself.” That, however, is an answer which in subtlety and ambiguity outdoes every utterance of the Pythian oracle. For it may just as well mean, “The consciousness of a self in me”--the expression of a pure absolute--as, “The consciousness conscious of itself”--the expression of a pure relative. Self-consciousness is the oracle of nature. Faith interprets this oracle in the former sense; science in the latter. Therewith, however, both are at odds with themselves. For a pure absolute that becomes conscious of itself, that enters into relation with itself, is an absolute no longer. And a pure relative that enters into relations with itself is equally no longer a pure relative. “Transcending these two opposites the Tathāgata points out the Truth in the Mean.” Is there any mean here betwixt these opposites? A wandering monk asks the Buddha:-- “How is it, Gotama? Is there an _I_?”--an Atta, self, as identical with itself. The Buddha remains silent. The other continues his question:-- “How is it, Gotama? Is there not an _I_?” The Buddha still maintains silence, and the other goes his way. If one does not understand the Buddha, it is impossible to interpret this colloquy other than does Oldenburg, for example, in his _Buddha_. But the meaning is quite otherwise than as there given. We here stand before that which from the standpoint of epistemology constitutes the keystone of the whole Buddha-thought. To understand it fully, we must take a plunge into the heart of modern physics. One of the most important forward steps taken by physics--if not technically, perhaps, yet easily the most important epistemologically--is its insight in the domain of interference phenomena, especially in the examples of the same afforded by light. A ray of light reflected back upon itself interferes with itself, _i.e._ it forms in itself “stationary waves” which present light as “non-light.”