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358 E. E. c. JONES : the past all motives must admit of mechanical statement, and the motions of matter and its configurations be the sole and sufficient reasons of all change ". Abstract, hypothetical, merely descriptive and only ap- proximately applicable to reality as this mechanical scheme is, it must no doubt be admitted that granted a knowledge of the positions and forces in a given system at a given moment, both future and past positions and forces might theoretically be deduced by an intellect " vast enough," on the supposition of there being no interference that is, no alteration from outside the system in quantity or direction of force. But since any scheme of the Universe is bound to take all the facts of experience into account, we must ask, what has the Mechanical Theory to say not only to the phenomena of life and mind, but also to the qualitative differences which are found even in inanimate objects ? Can these be in any way brought to a mechanical statement ? Such answer as can be supplied to this question, must be furnished by Molecular Mechanics. Can " all physical phenomena however complete, however ultimate, however numerous their qualitative diversities may be, and remain, for our perception . . . still be shown to correspond to, and be summed up by, purely dynamical equations, such equations describing the configurations and motions of a system of masses called molecules from their minuteness " ? As contrasted with Molar Mechanics, molecular mechanics turns out to be Indirect instead of Direct, and Ideal or Fictional instead of merely Abstract. It resolves the physi- cal characteristics of sensible bodies into mechanisms and these mechanisms into non-matter in motion. Thus it ceases to be even descriptive of " what actually goes on " in the real world, and its objects are mere fictions of the under- standing, not even conceivably presentable facts and we find that, even as regards inanimate things, the Mechanical Theory " begins with real bodies in empty space, and ends with ideal motions in an imperceptible plenum . . . begins with the dynamics of ordinary masses and ends with a medium that needs no dynamics or has dynamics of its own ". And if for Mass is substituted Energy, and for Mechanical Physics the Science of Energetics, the case does not seem to be much amended. According to this new doctrine all change is a transference or transformation of energy. But when we find that according to the accounts given by physicists matter is nothing but a vehicle or receptacle of Energy and cannot be known apart from energy, and that