ing, but that is not the nature of the velocity. It is continually changing. The velocity, therefore, of the descending stone never is any one velocity; it is always becoming another velocity. Its velocity, therefore, has no Being, because Being implies some continuance or permanence. It is properly called a Becoming. Such is one illustration by means of which you may be aided in familiarising your minds to the conception of Becoming, or process as distinguished from that of Being.
12. The illustration I gave you in the preceding paragraph may aid you in forming a conception of what is signified by the word Becoming, and of what Heraclitus meant by saying that all things are in a state of flux. The velocity of the descending stone is a phenomenon to which the term is cannot be properly, or at least without some qualification, applied at any moment of its transit. Take the smallest period of time you choose, say the one hundred millionth fraction of a second, and the changes in the velocity of the stone within that period are utterly incalculable, they are infinite. It is, I believe, with matters of this kind that the differential calculus deals. You will hear more about that elsewhere. Here we must deal with the question rather metaphysically than mathematically. I say then that the velocity of the stone changes infinitely, undergoes infinitude of changes, within any given time, however short. And this consideration prevents us from say-
