Page:Popular Science Monthly Volume 3.djvu/571

Rh finality. Matter no more proceeds from extension than extension proceeds from matter. This simple remark suffices to settle the difficulty of conceiving how the dimension of objects results from a group of dynamic points which have no dimension. Extension existing before every thing else, it is quite clear that, when certain primal energies come into union to give rise, through a thousand successive complications, to phenomena and to bodies, what they really produce is not the appearance of extension, which is the mere shadow of reality, but it is that collection of various and diverse activities which enable us to describe and define phenomena and bodies.

It is no longer a subject of doubt, in the minds of savants who have got beyond experimentation, that extension is an image and a show rather than an essential constituent property of bodies. The extension of bodies is a phenomenon which takes its rise in the collision of force with our minds. Charles de Rémusat, so long ago as 1842, gave an original and remarkable demonstration of this. He maintains that force is the cause of extension, meaning by that that the sensation of extension is a modification of our sensibility, occasioned by forces analogous to those which produce sensations of a more complex kind. When you experience an electric shock, you are struck. Percussion is the sensation of contact, in other words, of impulsion by something that has extension. Now, in this instance, Rémusat says, the cause of percussion, electricity, has no extension. Therefore, he adds, either electricity is nothing, or else it is a force which affects us in a way that may be compared to the effect of extension. So that a force, wanting the usual appearances of extension, may produce the same effects on us that a solid body in motion does. Within a few years a profound metaphysician, Magy, has pointed out by new arguments that corporeal extension is merely a show which springs from the internal reaction of the soul against the impression made on the sensorium, and which the soul translates to outward bodies, by a law analogous to that which makes it localize in the separate organs of sense the impression which it has nevertheless perceived only in the brain. Each sensation of taste, smell, light, or sound, is a phenomenon of psychological reaction which occurs in the soul when it is teased with a certain degree of energy by nerve-action, which in its turn depends on an outward action; but there is no relation of resemblance between the latter and the sensation it provokes. The ether, which, by its vibrations in unison with the elements of our retina, produces sensations of light in us, has in itself no luminosity. The proof of this is that two rays of light meeting under certain conditions may annul each other, and produce darkness. Now, Magy maintains that the subjectivity of extension is of the same order with that of light. Extension in general is explained by purely dynamic reasons, as readily as that particular extension is which serves as a kind of support for luminous phenomena, which evidently result from vibrations of the unextended