or does not exist, whereas the Indian thinker would concern himself with the problem of the reality of the Ego, and would see that what is real (or unreal) from one point of view may be unreal (or real) from another. The difference between the two ways of looking at things goes very deep; goes in fact to the root of most of the problems that perplex the student of Buddhism. Existence and non-existence are alternatives; and, if we are to choose between alternatives, we must provide ourselves with a criterion by which we may know the true alternative from the false. But how shall man, who is presumably not omniscient, provide himself with a criterion which will enable him to define the boundaries of the Universe? For it is this, and nothing less, that he attempts to do when he takes upon himself to divide things into the existent and the non-existent. What is the criterion or test of existence? It is impossible to answer this question except by begging it. In other words, we must say what we mean by existence before we can attempt to distinguish between the existent and the non-existent. But in the very act of defining the word, we provide ourselves, whether we intend to do this or not, with a test of the thing. For example. We ask ourselves: Does a certain thing exist or not? Does a centaur exist or not? Does a mermaid exist or not? It is easy for us to answer these questions, so long as we agree among ourselves that the existent is that which is perceptible by man's bodily senses. In thus defining the word existent, we provide ourselves with a test of existence; and the test is valid just so