There is, however, another kind of argument, which, while it does not establish idealism as a metaphysic, does, if valid, establish it as a practical policy. It is said that a proposition which is unverifiable has no meaning; that verification depends upon percepts; and that, therefore, a proposition about anything except actual or possible percepts is meaningless. I think that this view, strictly interpreted, would confine us to the first of the above four theories, and would forbid us to speak about anything that we have not ourselves explicitly noticed. If so, it is a view that no one can hold in practice, which is a defect in a theory that is advocated on practical grounds. The whole question of verification, and its connection with knowledge, is difficult and
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complex; I will therefore, leave it on one side for the present. The fourth of the above theories, which admits events that no one perceives, may also be defended by invalid arguments. It may be held that causality is known a priori, and that causal laws are impossible unless there are unperceived events. As against this, it may be urged that causality is not a priori, and that whatever regularity can be observed must be in relation to percepts. Whatever there is reason to believe in the laws of physics must, it would seem, be capable of being stated in terms of percepts. The statement may be odd and complicated; it may lack the characteristic of continuity which, until lately, was expected of a physical law. But it can hardly be impossible.
I conclude that there is no a priori objection to any one of our four theories. It is possible, however, to say that all truth is pragmatic, and that there is no pragmatic difference between the four theories. If this is true, we can adopt whichever we please, and the difference between them is only linguistic. I cannot accept this view; but this, also, is a matter for discussion at a later stage.
It remains to be asked whether any meaning can be attached to the words “mind” and “matter.” Every one knows that “mind” is what an idealist thinks there is nothing else but, and “matter” is what a materialist thinks the same about. The reader knows also, I hope, that idealists are virtuous and materialists are wicked. But perhaps there may be more than this to be said.
My own definition of “matter” may seem unsatisfactory; I should define it as what satisfies the equations of physics. There may be nothing satisfying these equations; in that case either physics or the concept “matter” is a mistake. If we reject substance, “matter” will have to be a logical construction. Whether it can be any construction composed of events–which may be partly inferred–is a difficult question, but by no means an insoluble one.
As for “mind,” when substance has been rejected a mind must be some group or structure of events. The grouping, must be effected by some relation which is characteristic of the sort of phenomena we wish to call “mental.” We may take memory as typical. We might-though this would be rather unduly simple-define a “mental” event as one which remembers or is remembered. Then the “mind” to which a given mental event belongs is the group of events connected with the given event by memory-chains, backwards or forwards.
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It will be seen that, according to the above definitions, a mind and a piece of matter are, each of them, a group of events. There is no reason why every event should belong to a group of one kind or the other, and there is no reason why some events should not belong to both groups; therefore some events may be neither mental nor material, and other events may be both. As to this, only detailed empirical considerations can decide.
CHAPTER XVII Hume
DAVID HUME ( 1711-76) is one of the most important among philosophers, because he developed to its logical conclusion the empirical philosophy of Locke and Berkeley, and by making it self-consistent made it incredible. He represents, in a certain sense, a dead end: in his direction, it is impossible to go further. To refute him has been, ever since he wrote, a favourite pastime among metaphysicians. For my part, I find none of their refutations convincing; nevertheless, I cannot but hope that something less sceptical than Hume’s system may be discoverable.
His chief philosophical work, the Treatise of Human Nature, was written while he was living in France during the years 1734 to 1737. The first two volumes were published in 1739, the third in 1740. He was a very young man, not yet in his thirties; he was not well known, and his conclusions were such as almost all schools would find unwelcome. He hoped for vehement attacks, which he would meet with brilliant retorts. Instead, no one noticed the book; as he says himself, “it fell dead-born from the press.” “But,” he adds, “being naturally of a cheerful and sanguine temper, I very soon recovered from the blow.” He devoted himself to the writing of essays, of which he produced the first volume in 1741. In 1744 he made an unsuccessful attempt to obtain a professorship at Edinburgh; having failed in this, he became first tutor to a lunatic and then secretary to a general.
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Fortified by these credentials, he ventured again into philosophy. He shortened the Treatise by leaving out the best parts and most of the reasons for his conclusions; the result was the Inquiry into Human Understanding, for a long time much better known than the Treatise. It was this book that awakened Kant from his “dogmatic slumbers”; he does not appear to have known the Treatise.
He wrote also Dialogues Concerning Natural Religion, which he kept unpublished during his lifetime. By his direction, they were published posthumously in 1779. His Essay on Miracles, which became famous, maintains that there can never be adequate historical evidence for such events.
His History of England, published in 1755 and following years, devoted itself to proving the superiority of Tories to Whigs and of Scotchmen to Englishmen; he did not consider history worthy of philosophic detachment. He visited Paris in 1763, and was made much of by the philosophes. Unfortunately, he formed a friendship with Rousseau, and had a famous quarrel with him. Hume behaved with admirable forbearance, but Rousseau, who suffered from persecution mania, insisted upon a violent breach.
Hume has described his own character in a self-obituary, or “funeral oration,” as he calls it: “I was a man of mild dispositions, of command of temper, of an open, social and cheerful humour, capable of attachment, but little susceptible of enmity, and of great moderation in all my passions. Even my love of literary fame, my ruling passion, never soured my temper, notwithstanding my frequent disappointments.” All this is borne out by everything that is known of him.
Hume Treatise of Human Nature is divided into three books, dealing respectively with the understanding, the passions, and morals. What is important and novel in his doctrines is in the first book, to which I shall confine myself.
He begins with the distinction between “impressions” and “ideas.” These are two kinds of perceptions, of which impressions are those that have more force and violence. “By ideas I mean the faint images of these in thinking and reasoning.” Ideas, at least when simple, are like impressions, but fainter. “Every simple idea has a simple impression, which resembles it; and every simple impression a correspondent idea.” “All our simple ideas in their first appearance are derived from simple impressions, which are correspondent to them, and which they
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exactly represent.” Complex ideas, on the other hand, need not resemble impressions. We can imagine a winged horse without having ever seen one, but the constituents of this complex idea are all derived from impressions. The proof that impressions come first is derived from experience; for example, a man born blind has no ideas of colours. Among ideas, those that retain a considerable degree of the vivacity of the original impressions belong to memory, the others to imagination.
There is a section (Book I, Part I, Sec. VII) “Of Abstract Ideas,” which opens with a paragraph of emphatic agreement with Berkeley’s doctrine that “all general ideas are nothing but particular ones, annexed to a certain term, which gives them a more extensive significance, and makes them recall upon occasion other individuals, which are similar to them.” He contends that, when we have an idea of a man, it has all the particularity that the impression of a man has. “The mind cannot form any notion of quantity or quality without forming a precise notion of degrees of each.””Abstract ideas are in themselves individual, however they may become general in their representation.” This theory, which is a modern form of nominalism, has two defects, one logical, the other psychological. To begin with the logical objection: “When we have found a resemblance among several objects,” Hume says, “we apply the same name to all of them.” Every nominalist would agree. But in fact a common name, such as “cat,” is just as unreal as the universal CAT is. The nominalist solution of the problem of universals thus fails through being insufficiently drastic in the application of its own principles; it mistakenly applies these principles only to “things,” and
