M.--One might reflect on such questions as, "What is consciousness? What triggers a perception? Can the mind know itself?" The answer to this last question, for instance, is that from a relative point of view we're quite clearly aware of our minds and can observe the movements and nature of our thoughts. Indeed, we'd be unable to function without being aware of our thoughts. But, in the final analysis, no thought could both think and know itself at the same time, just as a sword can't cut itself and an eye can't see itself. So here, in most examples of this kind, two kinds of reasoning or logic are distinguished. One is based on relative truth, or in other words on common sense, and the other on absolute truth. In the latter case, a final analysis shows that if consciousness existed as an independent entity, it could never both be and know itself at the same time. There are different philosophical schools in Buddhism, of different levels. Some say, in this case, that consciousness has an ultimate and independent reality and that it's self-aware by a process that doesn't imply a subject-object relationship, like a lamp flame that illuminates itself without needing any external source of light. Others would reply that a flame has no need to "illuminate" itself as it doesn't contain any darkness, and that if light could illuminate itself, darkness would also have to be able to darken itself.

J.F.--I don't want to deny the originality of Buddhist thinking in this field, but in what you've just said I recognize a whole classic problem in Western philosophy. Can the mind know itself, for example? This is what we call the problem of the possibility of introspective thought. In perception, or in knowledge, can we be simultaneously aware of the object perceived or known, and of our own thought as a conscious agent? Some psychologists think that introspection is possible, while others think that we're not good enough judges to examine ourselves and that observing our inner life by itself is unreliable; only by observing behavior can we ever hope to find out where it comes from.

M.--That last point of view, of course, would exclude any contemplative knowledge, which is Buddhism's very essence. If you think about it, one of the main things that distinguishes what's conscious from what's inanimate is exactly that faculty of self-examination. It's the unique characteristic of the mind. So that reluctance to explore the nature of the mind through introspection, rather than limiting oneself to what's measurable or detectable by physical means, is self-defeating. Buddhist and other contemplators have been applying themselves to the introspective approach for more than two thousand years. Using mechanical instruments is hardly likely to teach one anything about the nature of the mind, because what one will be studying and measuring will only be the nervous system's input and output. Consciousness itself will be left out of the investigation. Only the mind can know and analyze the mind.

--Jean-François Revel & Matthieu Ricard, The Monk and the Philosopher, pp. 80-81