CHAPTER VI.

LANGUAGE-PROPOSITIONS CONCERNING NECESSARY TRUTHS.

THOUGH We may accept Hume's conclusion that speechless animals think, believe, and reason; yet, it must be borne in mind, that there is an important difference between the signification of the terms when applied to them and when applied to those animals which possess language. The thoughts of the former are trains of mere feelings; those of the latter are, in addition, trains of the ideas of the signs which represent feelings, and which are called "words."

A word, in fact, is a spoken or written sign, the idea of which is, by repetition, so closely associated with the idea of the simple or complex feeling which it represents, that the association becomes indissoluble. No Englishman, for example, can think of the word "dog" without immediately having the idea of the group of impressions to which that name is given; and conversely, the group of impressions immediately calls up the idea of the word "dog."

The association of words with impressions and ideas is the process of naming; and language approaches perfection, in proportion as the shades of difference between various ideas and impressions are represented by differences in their names.

The names of simple impressions and ideas, or of

groups of co-existent or successive complex impressions and ideas, considered per se, are substantives; as redness, dog, silver, mouth; while the names of impressions or ideas considered as parts or attributes of a complex whole, are adjectives. Thus redness, considered as part of the complex idea of a rose, becomes the adjective red; flesheater, as part of the idea of a dog, is represented by carnivorous; whiteness, as part of the idea of silver, is white; and so on.

The linguistic machinery for the expression of belief is called predication; and, as all beliefs express ideas of relation, we may say that the sign of predication is the verbal symbol of a feeling of relation. The words which serve to indicate predication are verbs. If I say "silver" and then "white," I merely utter two names; but if I interpose between them the verb "is," I express a belief in the co-existence of the feeling of whiteness with the other feelings which constitute the totality of the complex idea of silver; in other words, I predicate "whiteness" of silver.

In such a case as this, the verb expresses predication and nothing else, and is called a copula. But, in the great majority of verbs, the word is the sign of a complex idea, and the predication is expressed only by its form. Thus in "silver shines," the verb "to shine" is the sign for the feeling of brightness, and the mark of predication lies in the form "shine-s."

Another result is brought about by the forms of verbs. By slight modifications they are made to indicate that a belief, or predication, is a memory, or is an expectation. Thus "silver shone" expresses a memory ; "silver will shine" an expectation.

The form of words which expresses a predication is

a proposition. Hence, every predication is the verbal equivalent of a belief; and, as every belief is either an immediate consciousness, a memory, or an expectation, and as every expectation is traceable to a memory, it follows that, in the long run, all propositions express either immediate states of consciousness, or memories. The proposition which predicates A of X must mean either, that the fact is testified by my present consciousness, as when I say that two colours, visible at this moment, resemble one another; or that A is indissolubly associated with X in memory; or that A is indissolubly associated with X in expectation. But it has already been shown that expectation is only an expression of memory.

Hume does not discuss the nature of language, but so much of what remains to be said, concerning his philosophical tenets, turns upon the value and the origin of verbal propositions, that this summary sketch of the relations of language to the thinking process will probably not be deemed superfluous.

So large an extent of the field of thought is traversed by Hume, in his discussion of the verbal propositions in which mankind enshrine their beliefs, that it would be impossible to follow him throughout all the windings of his long journey, within the limits of this essay. purpose, therefore, to limit myself to those propositions which concern-1. Necessary Truths; 2. The order of Nature; 3. The Soul; 4. Theism; 5. The Passions and Volition; 6. The Principle of Morals.

Hume's views respecting necessary truths, and more particularly concerning causation, have, more than any other part of his teaching, contributed to give him a prominent place in the history of philosophy.

"All the objects of human reason and inquiry may naturally be divided into two kinds, to wit, relations of ideas and matters of fact. Of the first kind are the sciences of geometry, algebra, and arithmetic, and, in short, every affirmation which is either intuitively or demonstratively certain. That the square of the hypothenuse is equal to the square of the two sides, is a proposition which expresses a relation between these two figures. That three times five is equal to the half of thirty, expresses a relation between these numbers. Propositions of this kind are discoverable by the mere operation of thought without dependence on whatever is anywhere existent in the universe. Though there never were a circle or a triangle in nature, the truths demonstrated by Euclid would for ever retain their certainty and evidence.

"Matters of fact, which are the second objects of human reason, are not ascertained in the same manner, nor is an evidence of their truth, however great, of a like nature with the foregoing. The contrary of every matter of fact is still possible, because it can never imply a contradiction, and is conceived by the mind with the same facility and distinctness, as if ever so conformable to reality. That the sun will not rise to-morrow, is no less intelligible a proposition, and implies no more contradiction, than the affirmation, that it will rise. We should in vain, therefore, attempt to demonstrate its falsehood. Were it demonstratively false, it would imply a contradiction, and could never be distinctly conceived by the mind."-(IV. pp. 32, 33.)

The distinction here drawn between the truths of geometry and other kinds of truth is far less sharply indicated in the Treatise, but as Hume expressly disowns any opinions on these matters but such as are expressed in the Inquiry, we may confine ourselves to the latter; and it is needful to look narrowly into the propositions here laid down, as much stress has been laid upon Hume's admission that the truths of mathematics are intuitively and demonstratively certain; in

other words, that they are necessary and, in that respect, differ from all other kinds of belief.

What is meant by the assertion that "propositions of this kind are discoverable by the mere operation of thought without dependence on what is anywhere existent in the universe"?

Suppose that there were no such things as impressions of sight and touch anywhere in the universe, what idea could we have even of a straight line, much less of a triangle and of the relations between its sides? The fundamental proposition of all Hume's philosophy is that ideas are copied from impressions; and, therefore, if there were no impressions of straight lines and triangles there could be no ideas of straight lines and triangles. But what we mean by the universe is the sum of our actual and possible impressions.

So, again, whether our conception of number is derived from relations of impressions in space or in time, the impressions must exist in nature, that is, in experience, before their relations can be perceived. Form and number are mere names for certain relations between matters of fact; unless a man had seen or felt the difference between a straight line and a crooked one, straight and crooked would have no more meaning to him, than red and blue to the blind.

The axiom, that things which are equal to the same are equal to one another, is only a particular case of the predication of similarity; if there were no impressions, it is obvious that there could be no predicates. But what is an existence in the universe but an impression?

If what are called necessary truths are rigidly analysed, they will be found to be of two kinds. Either they depend on the convention which underlies the