Materialism presents at first sight the data out of which to construct a theory of memory, for it recognises the dependent character of consciousness and takes body to be its substance. Does the body show any marks or traces of thought that may serve to revive ideas in the absence of objects? None have yet been discovered. Nerves are used in objective observation, but they do not appear to be essential either to recollection in general or to any of the more elaborate forms of internal thought. The brain is used only when giving expression to thought. Memory is noticed by everyone, even the least metaphysical. Persons who are incapable of understanding the difference between object and subject or general and particular, are yet perfectly well aware of the difference between remembering and forgetting. The phrases relating to this distinction are the commonest in every language. Memory is conspicuous--notorious--palpable. It is the pivot on which the whole mental system revolves. It cannot be gainsaid or ignored. There is no profit in boycotting it in the manner recommended by Mill--it must be faced and explained. 'How do you account for memory?' should be the first question addressed to one who pretends to have a science of mind. If he has no plausible answer to give, his system is not worth discussion. A philosophy without a theory of memory is like an astronomy without gravitation. X--MEMORY OF SENTIMENTS Sentiments are remembered and recollected like objects. For instance, a boy is punished for doing wrong and has _pain_; he does wrong again and is haunted with the _fear_ of being punished again, which is the recollected and anticipated pain. We have thus two species of sentiment corresponding exactly to object and idea. The word 'feeling' is appropriate to the first, 'emotion' to the second. 'Passion' is a strong degree of either. Objects that are associated with feelings are better remembered than those that merely affect the intellect, for there is a double memory at work--one in the core and one on the surface of our mind. Sentiments are not susceptible of the same degree of analysis as objects. The inner matrix is more fluid and does not keep details. Apart from the objects associated with feelings, there is not much opportunity or need for classifying them. We are happy, wretched, or indifferent--that sums up the sentimental experience.