The derivation of Reason as given in the preceding sections may be summed up thus:--the meeting of Minds gives Perception or primary experience; Attention selects therefrom objects of special interest to the observer; Memory retains impressions of these in the mental plasma, by which ideas of them are recollected though the originating mind be not present; community with divergence of imprint gives rise to Comparison; from this are derived Imagination and Generalisation; from imagination emerge Reason and Art. Generalisation is thus only a collateral relation of reason, not its immediate parent nor in the direct line of descent. It is not essential to reason, but may enter as a subsidiary process into an argument. If the things we argue about are numerous it will be more correct to generalise them and then argue from the general idea, than to argue from one concrete object to another. But innumerable inferences are drawn from one particular thing to another, and these involve no generalisation. Reason is chiefly the art of predicting by means of the intellect what will occur to us in the future. Its use is to enable us to prepare for future events in so far as our resources permit. We never predict quite accurately, but general preconceptions are better than none at all. The same process by which we preconceive the future can be applied to the conception of what is actually taking place but not within our ken--as at the antipodes--and can be applied also to events that took place in the past and will never be experienced by us. It might be objected that as regards the past we can have no motive in imagining it, seeing we can never experience it. But a conception of the past is often a necessary condition of our conceiving the future, and is artistically interesting. It awakens pleasing emotions to be able to picture to ourselves, even imperfectly, states of the world and of society that have long been obsolete. An investigation of the manner in which reason supplies us with ideas of the unknown, involves the consideration and arrangement of so many details that it may be regarded as a small science in itself--DIALECTIC. A dialectician (logician in the narrower sense) is neither a grammarian nor an encyclopedia of the best information on every subject. His office consists in deciding whether certain theorems are arguments or not. An ARGUMENT is an act or product of rational imagination. Theorems which purport to be arguments, but are not, are FALLACIES.