reality corresponding to our general ideas and about the universal and the individual (the controversy of Nominalist and of the unhappily so-called Realist), is a wholly antiquated mediaeval absurdity, have curiously failed to observe the signs of our own times, and the trend of this characteristic ontology of our present century and of current science. What are Mill’s Permanent Possibilities of Sensation, if you view them as objectively valid at all, and not as mere private expectations of our present feeling, — what are they, I ask, but explicit universals? What sort of an individual fact or being is a mere “possibility”? Kant’s empirical objects, or Gegenstände der Möglichen Erfahrung, — his substances, causes, and the rest, what are they but products of the categorizing Understanding, empirically valid general truths? If one passes from the more abstract formulas to the concrete cases, glance, if you please, at that most potent conception, the modern notion of Energy. I ask not here as to its empirical basis nor as to its outcome, but solely as to its ontological character as a mere conception. Energy, one may say, is indeed phenomenally real. Professor Tait’s remarkable words as to the objective reality implied by the permanence of Energy have often been quoted. But nobody of any authority, I suppose, is yet prepared to maintain in any decisive way that the energy of the physical world consists of a collection of ultimate individual units or bits of energy, which retain their individual identity, and as individuals transfer themselves from one part of matter to another. The idea has been suggested, but so far not vindicated. In
