It is no doubt true, here again, that such judgments cannot be called final, and that not all scientific men will accept them as they stand. But all alike are forced to agree that our previous notions are completely upset, and that we are compelled to recognize the fact that of these fundamental questions we know far less than the little we seemed to know. What, then, is to be thought of Professor Haeckel's confident utterances, which could be justified only on the supposition that we know everything? And what becomes of the famous Law of Substance, if both its parts are found thus to contradict the conclusion he would draw from it? The case is thus summed up by the writer of the article just cited: The discovery of radio-activity is one of the most momentous in the history of science. "There has been a vivid new start" (we again borrow Sir William Crookes' expression). "Our physicists have remodelled their views as to the constitution of matter." The remodelling indeed has hardly commenced.... What is undeniable is that the Daltonian atom has, within a century of its acceptance as a fundamental reality, suffered disruption. Its proper place in nature is not that formerly assigned to it, ... its reputation for inviolability and indestructibility is gone for ever. Each of these supposed "ultimates" is now known to be the scene of indescribable activities, a complex piece of mechanism composed of thousands of parts, a star-cluster in miniature, subject to all kinds of dynamical vicissitudes, to perturbation, acceleration, internal friction, total or partial disruption. And to each is appointed a fixed term of existence. Sooner or later, the balance of equilibrium is tilted, disturbance eventuates in overthrow; the tiny exquisite system finally breaks up. Of atoms, as of men, it may be said with truth, "_Quisque suos patitur manes_." "Here," in fact, "we meet the impenetrable secret of creative agency."[62] IX THE PROBLEM OF LIFE