(M224) The most recent researches in physical science tend apparently rather to confirm than to invalidate these general views of the nature of the universe; for if modern physicists are right in regarding the constitution of matter as essentially electrical, the antagonistic forces of attraction and repulsion postulated by Empedocles and Spencer would resolve themselves into positive and negative electricity. On the other hand the atomic disintegration which is now known to be proceeding in certain of the chemical elements, particularly in uranium and radium, and which is probably proceeding in all, suggests a doubt whether the universe is really, as Spencer supposed, in process of integration and evolution and not rather in process of disintegration and dissolution; or whether perhaps the apparent evolution of the organic world is not attended by a simultaneous dissolution of the inorganic, so that the fabric of the universe would be a sort of Penelope’s web, which the great artificer weaves and unweaves at the same time.(919) With such a grave doubt to trouble the outlook on the future, we may perhaps say that Empedocles was wiser than Herbert Spencer in leaving, as he apparently did, the question undecided, whether during the epoch open to human observation the force of attraction or that of repulsion has been and is predominant, and consequently whether matter as a whole is integrating or disintegrating, whether all things are gradually evolving into more complex and concentrated forms, or are gradually dissolving and wasting away, through simpler and simpler forms, into the diffused tenuity of their primordial constituents. (M225) Just as in his view of the constitution and history of the physical universe Empedocles anticipated to some extent the theories of Spencer, so in his view of the development of living beings he anticipated to some extent the theories of Darwin; for he held that the existing species of animals have been evolved out of inorganic matter through intermediate sorts of monstrous creatures, which, being ill fitted to survive, gradually succumbed and were exterminated in the struggle for existence.(920) Whether Empedocles himself clearly enunciated the principle of the survival of the fittest as well as the doctrine of evolution, we cannot say with certainty; but at all events it is significant that Aristotle, after stating for the first time the principle of the survival of the fittest, illustrates it by a reference to Empedocles’s theory of the extinction of monstrous forms in the past, as if he understood the theory to imply the principle.(921)