Permanent 'things' again; the 'same' thing and its various 'appearances' and 'alterations'; the different 'kinds' of thing; with the 'kind' used finally as a 'predicate,' of which the thing remains the 'subject'—what a straightening of the tangle of our experience's immediate flux and sensible variety does this list of terms suggest! And it is only the smallest part of his experience's flux that anyone actually does straighten out by applying to it these conceptual instruments. Out of them all our lowest ancestors probably used only, and then most vaguely and inaccurately, the notion of 'the same again.' But even then if you had asked them whether the same were a 'thing' that had endured throughout the unseen interval, they would probably have been at a loss, and would have said that they had never asked that question, or considered matters in that light.
Kinds, and sameness of kind—what colossally useful DENKMITTEL for finding our way among the many! The manyness might conceivably have been absolute. Experiences might have all been singulars, no one of them occurring twice. In such a world logic would have had no application; for kind and sameness of kind are logic's only instruments. Once we know that whatever is of a kind is also of that kind's kind, we can travel through the universe as if with seven-league boots. Brutes surely never use these abstractions, and civilized men use them in most various amounts.
Causal influence, again! This, if anything, seems to have been an antediluvian conception; for we find primitive men thinking that almost everything is significant and can exert influence of some sort. The search for the more definite influences seems to have started in the question: "Who, or what, is to blame?"—for any illness, namely, or disaster, or untoward thing. From this centre the search for causal influences has spread. Hume and 'Science' together have tried to eliminate the whole notion of influence, substituting the entirely different DENKMITTEL of 'law.' But law is a comparatively recent invention, and influence reigns supreme in the older realm of common sense.
The 'possible,' as something less than the actual and more than the wholly unreal, is another of these magisterial notions of common sense. Criticize them as you may, they persist; and we fly back to them the moment critical pressure is relaxed. 'Self,' 'body,' in the substantial or metaphysical sense—no one escapes subjection to THOSE forms of thought. In practice, the common-sense DENKMITTEL are uniformly victorious. Everyone, however instructed, still thinks of a 'thing' in the common-sense way, as a permanent unit-subject that 'supports' its attributes interchangeably. No one stably or sincerely uses the more critical notion, of a group of sense-qualities united by a law. With these categories in our hand, we make our plans and plot together, and connect all the remoter parts of experience with what lies before our eyes. Our later and more critical philosophies are mere fads and fancies compared with this natural mother-tongue of thought.
Common sense appears thus as a perfectly definite stage in our understanding of things, a stage that satisfies in an extraordinarily successful way the purposes for which we think. 'Things' do exist, even when we do not see them. Their 'kinds' also exist. Their 'qualities' are what they act by, and are what we act on; and these also exist. These lamps shed their quality of light on every object in this room. We intercept IT on its way whenever we hold up an opaque screen. It is the very sound that my lips emit that travels into your ears. It is the sensible heat of the fire that migrates into the water in which we boil an egg; and we can change the heat into coolness by dropping in a lump of ice. At this stage of philosophy all non-European men without exception have remained. It suffices for all the necessary practical ends of life; and, among our own race even, it is only the highly sophisticated specimens, the minds debauched by learning, as Berkeley calls them, who have ever even suspected common sense of not being absolutely true.
But when we look back, and speculate as to how the common-sense categories may have achieved their wonderful supremacy, no reason appears why it may not have been by a process just like that by which the conceptions due to Democritus, Berkeley, or Darwin, achieved their similar triumphs in more recent times. In other words, they may have been successfully DISCOVERED by prehistoric geniuses whose names the night of antiquity has covered up; they may have been verified by the immediate facts of experience which they first fitted; and then from fact to fact and from man to man they may have SPREAD, until all language rested on them and we are now incapable of thinking naturally in any other terms. Such a view would only follow the rule that has proved elsewhere so fertile, of assuming the vast and remote to conform to the laws of formation that we can observe at work in the small and near.
For all utilitarian practical purposes these conceptions amply suffice; but that they began at special points of discovery and only gradually spread from one thing to another, seems proved by the exceedingly dubious limits of their application to-day. We assume for certain purposes one 'objective' Time that AEQUABILITER FLUIT, but we don't livingly believe in or realize any such equally-flowing time. 'Space' is a less vague notion; but 'things,' what are they? Is a constellation properly a thing? or an army? or is an ENS RATIONIS such as space or justice a thing? Is a knife whose handle and blade are changed the 'same'? Is the 'changeling,' whom Locke so seriously discusses, of the human 'kind'? Is 'telepathy' a 'fancy' or a 'fact'? The moment you pass beyond the practical use of these categories (a use usually suggested sufficiently by the circumstances of the special case) to a merely curious or speculative way of thinking, you find it impossible to say within just what limits of fact any one of them shall apply.
The peripatetic philosophy, obeying rationalist propensities, has tried to eternalize the common-sense categories by treating them very technically and articulately. A 'thing' for instance is a being, or ENS. An ENS is a subject in which qualities 'inhere.' A subject is a substance. Substances are of kinds, and kinds are definite in number, and discrete. These distinctions are fundamental and eternal. As terms of DISCOURSE they are indeed magnificently useful, but what they mean, apart from their use in steering our discourse to profitable issues, does not appear. If you ask a scholastic philosopher what a substance may be in itself, apart from its being the support of attributes, he simply says that your intellect knows perfectly what the word means.
But what the intellect knows clearly is only the word itself and its steering function. So it comes about that intellects SIBI PERMISSI, intellects only curious and idle, have forsaken the common-sense level for what in general terms may be called the 'critical' level of thought. Not merely SUCH intellects either—your Humes and Berkeleys and Hegels; but practical observers of facts, your Galileos, Daltons, Faradays, have found it impossible to treat the NAIFS sense-termini of common sense as ultimately real. As common sense interpolates her constant 'things' between our intermittent sensations, so science EXTRApolates her world of 'primary' qualities, her atoms, her ether, her magnetic fields, and the like, beyond the common-sense world. The 'things' are now invisible impalpable things; and the old visible common-sense things are supposed to result from the mixture of these invisibles. Or else the whole NAIF conception of thing gets superseded, and a thing's name is interpreted as denoting only the law or REGEL DER VERBINDUNG by which certain of our sensations habitually succeed or coexist.
Science and critical philosophy thus burst the bounds of common sense. With science NAIF realism ceases: 'Secondary' qualities become unreal; primary ones alone remain. With critical philosophy, havoc is made of everything. The common-sense categories one and all cease to represent anything in the way of BEING; they are but sublime tricks of human thought, our ways of escaping bewilderment in the midst of sensation's irremediable flow.