Leaving relativity aside for the moment, modern physics has provided proof of the atomic structure of ordinary matter, while not disproving the arguments in favor of the ether, to which no such structure is attributed. The result was a sort of compromise between the two views, the one applying to what was called “gross” matter, the other to the ether. There can be no doubt about electrons and protons, though, as we shall see shortly, they need not be conceived as atoms were conceived traditionally. As for the ether, its status is very curious: many physicists still maintain that, without it, the propagation of light and other electromagnetic waves would be inconceivable, but except in this way it is difficult to see what purpose it serves. The truth is, I think, that relativity demands the abandonment of the old conception of “matter,” which is infected by the metaphysics associated with “substance,” and represents a point of view not really necessary in dealing with phenomena. This is what we must now investigate. In the old view, a piece of matter was something which survived all through time, while never being at more than one place at a given time. This way of looking at things is obviously connected with the complete separation of space and time in which people formerly believed. When we substitute space-time for space and time, we shall naturally expect to derive the physical world from constituents which are as limited in time as in space. Such constituents are what we call “events.” An event does not persist and move, like the traditional piece of matter; it merely exists for its little moment and then ceases. A piece of matter will thus be resolved into a series of events. Just as, in the old view, an extended body was composed of a number of particles, so, now, each particle, being extended in time, must be regarded as composed of what we may call “event-particles.” The whole series of these events makes up the whole history of the particle, and the particle is regarded as _being_ its history, not some metaphysical entity to which the events happen. This view is rendered necessary by the fact that relativity compels us to place time and space more on a level than they were in the older physics.