Page:Popular Science Monthly Volume 48.djvu/667

Rh of the phenomena in a system of moving mass-points is the end which the theory of Nature is trying to reach. If this principle falls, and we have seen that it must fall, the ignorabimus falls with it, and science again has free course.

I do not believe that you will accept this result with surprise, for, if I can judge from my own experience, hardly a naturalist has seriously believed in the ignorabimus unless he has failed to make clear to himself in what point that in it which is untenable lies. But the gain to the negative criticism of the mechanical theory of the world accruing from the formal laying of that menacing specter may be of some value to many thinkers who have nothing to oppose to the inevitable logic of Du Bois-Reymond's demonstration.

What is here laid down for the sake of clearness, in respect to these particular discussions, has, however, a considerably wider bearing. The refutation of the mechanical construction of the universe touches the basis of the whole materialistic theory of the world, the terms being taken in the scientific sense. It appears a vain undertaking, with ultimate failure decreed to every earnest effort, to interpret known physical phenomena mechanically; hence the conclusion is unavoidable that the attempt can still less succeed with the vastly more complicated phenomena of organic life. The same contradiction of principle forces itself upon us here, and the supposition that all natural phenomena can be traced back primarily to mechanical factors can not even be designated an available working hypothesis. It is a mere error.

The following fact bears most plainly against this error: Mechanical equations all have the property of permitting the exchange of the sign of time that is, the theoretically perfected mechanical processes can as well go backward as forward. In a purely mechanical world there are therefore no earlier and later in the sense of our world: the tree might be changed into a twig or a seed, the butterfly to a caterpillar, and the old man to a child. The mechanical theory has no explanation of the fact that this does not take place, and, on account of the property of mechanical equations which we have mentioned, can have none. The actual irreversibility of real phenomena also demonstrates the existence of processes that are not representable by mechanical equations; and with this the condemnation of scientific materialism is pronounced.

It thus appears to result certainly from these considerations that we shall have finally to renounce the hope of explaining the physical world intuitively by tracing its phenomena back to a mechanics of the atoms. But, I hear it said, if the conception of moving atoms is taken away from us, what means is left of