[281] It may deserve to be remarked that Hobbes himself, nominalist as he was, did not limit reasoning to comparison of proposition, as some later writers have been inclined to do, and as in his objections to Descartes, he might seem to do himself. This may be inferred from the sentence quoted in the text, and more expressly, though not quite perspicuously, from a passage in the Computatio, sive Logica, his Latin treatise published after the Leviathan. Quomodo autem animo sine verbis tacita cogitatione ratiocinando addere et subtrahere solemus uno aut altero exemplo ostendendum est. Si quis ergo e longinquo aliquid obscurè videat, etsi nulla sint imposita vocabula, habet tamen ejus rei ideam eandem propter quam impositis nunc vocabulis dicit eam rem esse corpus. Postquam autem propius accesserit, videritque eandem rem certo quodam modo nunc uno, nunc alio in loco esse, habebit ejusdem ideam novam, propter quam nunc talem rem animatam vocat, &c., p. 2.
[282] The demonstration of the thirty-second proposition of Euclid could leave no one in doubt whether this property were common to all triangles, after it had been proved in a single instance. It is said, however, to be recorded by an ancient writer, that this discovery was first made as to equilateral, afterwards as to isosceles, and lastly as to other triangles. Stewart’s philosophy of Human Mind, vol. ii., chap., iv., sect. 2 The mode of proof must have been different from that of Euclid. And this might possibly lead us to suspect the truth of the tradition. For if the equality of the angles of a triangle to two right angles admitted of any elementary demonstration, such as might occur in the infancy of geometry, without making use of the property of parallel lines, assumed in the twelfth axiom of Euclid, the difficulties consequent on that assumption would readily be evaded. See the Note on Euclid, i. 29. in Playfair, who has given a demonstration of his own, but one which involves the idea of motion rather more than was usual with the Greeks in their elementary propositions.
[283] Lev.
The subject continued. 126. The equivocal use of names makes it often difficult to recover those conceptions for which they were designed “not only in the language of others, wherein we are to consider the drift and occasion and contexture of the speech, as well as the words themselves, but in our own discourse, which, being derived from the custom and common use of speech, representeth unto us not our own conceptions. It is, therefore, a great ability in a man, out of the words, contexture and other circumstances of language to deliver himself from equivocation, and to find out the true meaning of what is said; and this is it we call understanding.”[284] If speech be peculiar to man, as for aught I know it is, then is understanding peculiar to him also; understanding being nothing else but conception caused by speech.”[285] This definition is arbitrary and not conformable to the usual sense. “True and false,” he observes afterwards, “are attributes of speech not of things; where speech is not, there is neither truth nor falsehood, though there may be error. Hence, as truth consists in the right ordering of names in our affirmations, a man that seeks precise truth hath need to remember what every word he uses stands for and place it accordingly. In geometry, the only science hitherto known, men begin by definitions. And every man who aspires to true knowledge, should examine the definitions of former authors, and either correct them or make them anew. For the errors of definitions multiply themselves, according as the reckoning proceeds, and lead men into absurdities, which at last they see, but cannot avoid without reckoning anew from the beginning in which lies the foundation of their errors.... In the right definition of names, lies the first use of speech, which is the acquisition of science. And in wrong or no definitions lies the first abuse from which proceed all false and senseless tenets, which make those men that take their instruction from the authority of books, and not from their own meditation, to be as much below the condition of ignorant men, as men endued with true science are above it. For between true science and erroneous doctrine, ignorance is in the middle. Words are wise men’s counters, they do but reckon by them; but they are the money of fools.”[286]
[284] Hum. Nat.
[285] Lev.
[286] Lev.
Names differently imposed. 127. “The names of such things as affect us, that is, which please and displease us, because all men be not alike affected with the same thing, nor the same man at all times, are in the common discourse of men of inconstant signification. For seeing all names are imposed to signify our conceptions, and all our affections are but conceptions, when we conceive the same thoughts differently, we can hardly avoid different naming of them. For though the nature of that we conceive be the same, yet the diversity of our reception of it, in respect of different constitutions of body and prejudices of opinion, gives everything a tincture of our different passions. And therefore, in reasoning, a man must take heed of words, which, besides the signification of what we imagine of their nature, have a signification also of the nature, disposition and interest of the speaker; such as are the names of virtues and vices; for one man calleth wisdom what another calleth fear, and one cruelty, what another justice; one prodigality, what another magnanimity, and one gravity what another stupidity, &c. And therefore such names can never be true grounds of any ratiocination. No more can metaphors and tropes of speech, but these are less dangerous, because they profess their inconstancy, which the other do not.”[287] Thus ends this chapter of the Leviathan, which, with the corresponding one in the Treatise of Human Nature, are, notwithstanding what appear to be some erroneous principles, as full, perhaps, of deep and original thoughts as any other pages of equal length on the art of reasoning and philosophy of language. Many have borrowed from Hobbes without naming him; and in fact he is the founder of the nominalist school in England. He may probably have conversed with Bacon on these subjects; we see much of that master’s style of illustration. But as Bacon was sometimes too excursive to sift particulars, so Hobbes has sometimes wanted a comprehensive view.
[287] Lev.
Knowledge. 128. “There are,” to proceed with Hobbes, “two kinds of knowledge; the one, sense, or knowledge original, and remembrance of the same; the other, science, or knowledge of the truth of propositions, derived from understanding. Both are but experience, one of things from without, the other from the proper use of words in language, and experience being but remembrance, all knowledge is remembrance. Knowledge implies two things, truth and evidence; the latter is the concomitance of a man’s conception with the words that signify such conception in the act of ratiocination.” If a man does not annex a meaning to his words, his conclusions are not evident to him. “Evidence is to truth, as the sap to the tree, which, so far as it creepeth along with the body and branches, keepeth them alive; when it forsaketh them they die; for this evidence, which is meaning with our words, is the life of truth.” “Science is evidence of truth, from some beginning or principle of sense. The first principle of knowledge is that we have such and such conceptions; the second that we have thus and thus named the things whereof they are conceptions; the third is that we have joined those names in such manner as to make true propositions; the fourth and last is that we have joined these propositions in such a manner as they be concluding, and the truth of the conclusion said to be known.”[288]