1441 CHAP. XII. BOOK IV. apt to do,) till we have very well examined particulars, and made several experiments, in that thing which we would explain by our hypothesis, and see whether it will agree to them all; whether our principles will carry us quite through, and not be as inconsistent with one phenomenon of nature, as they seem to accommodate and explain another. And at least that we take care that the name of principles deceive us not, nor impose on us, by making us receive that for an unquestionable truth, which is really at best but a very doubtful conjecture; such as are most (I had almost said all) of the hypotheses in natural philosophy 1. Clear and distinct Ideas with settled Names, and the finding of those inter mediate ideas which show their 14. But whether natural philosophy be capable of certainty 2 or no, the ways to enlarge our knowledge, as far as we are capable, seems to me, in short, to be these two : First, The first is to get and settle in our minds [3 determined ideas of those things whereof we have general or specific names; at least, so many of them as we would consider and improve our knowledge in, or reason about.] [*And if they be specific ideas of substances, we should endeavour also Agree- to make them as complete as we can, whereby I mean, that ment or we should put together as many simple ideas as, being conment, are stantly observed to co-exist, may perfectly determine the the Ways species; and each of those simple ideas which are the ingreto enlarge our Know- dients of our complex ones, should be clear and distinct in ledge. our minds.] For it being evident that our knowledge cannot exceed our ideas; [5 as far as] they are either imperfect, confused, or obscure, we cannot expect to have certain, perfect, or clear knowledge. Disagree 1 Cf. Bk. I. ch. iii. §§ 23, 24; ch. vii. It is against those spurious axioms, or dogmatic (as distinguished from sug. gestive) hypotheses, that he contends throughout his controversy with 'innate ideas and principles '-not against self-evident truths of reason, which, even in their most abstract form, may help at least to 'silence wranglers.' 2 'capable of certainty,' i. e. of rising into the certainty of 'knowledge,' as distinct from presumption that rests on the custom of experience. 3 In first edition-'as far as we can, clear, distinct, and constant ideas of those things we would consider and know.' * Added in fourth edition. where'-in first three editions. • This sentence was quoted by Stillingfleet, to show that Locke's theory of knowledge is inconsistent with recognition of mysteries in religion. Locke replied that he did not place certainty in perfect clearness of idea: he only held that there could not be A Secondly, The other is the art of finding out those inter- BOOK IV. mediate ideas, which may show us the agreement or repugnancy of other ideas, which cannot be immediately compared. CHAP. XII. matics an 15. That these two (and not the relying on maxims, and Mathedrawing consequences from some general propositions) are instance the right methods of improving our knowledge in the ideas of this. of other modes besides those of quantity, the consideration of mathematical knowledge will easily inform us. Where first we shall find that he that has not a perfect and clear idea of those angles or figures of which he desires to know anything, is utterly thereby incapable of any knowledge about them. Suppose but a man not to have a perfect exact idea of a right angle, a scalenum, or trapezium, and there is nothing more certain than that he will in vain seek any demonstration about them. Further, it is evident, that it was not the influence of those maxims which are taken for principles in mathematics, that hath led the masters of that science into those wonderful discoveries they have made. Let a man of good parts know all the maxims generally made use of in mathematics ever so perfectly, and contemplate their extent and consequences as much as he pleases, he will, by their assistance, I suppose, scarce ever come to know that the square of the hypothenuse in a right-angled triangle is equal to the squares of the two other sides. The knowledge that 'the whole is equal to all its parts,' and 'if you take equals from equals, the remainder will be equal,' &c., helped him not, I presume, to this demonstration: and a man may, I think, pore long enough on those axioms, without ever seeing one jot the more of mathematical truths. They have been discovered by the thoughts otherwise applied: the mind had other objects, other views before it, far different from those maxims, when it first got the knowledge of such truths in mathematics, which men, well enough acquainted with those received axioms, but ignorant of their method who first made these demonstrations, can never sufficiently admire. And who knows what methods to enlarge our knowledge knowledge of those relations of an idea that are obscure; but an obscure idea might be clear and cognizable in some of its relations. Hence the additions BOOK IV. in other parts of science may hereafter be invented, answering that of algebra in mathematics, which so readily finds out the ideas of quantities to measure others by; whose equality or proportion we could otherwise very hardly, or, perhaps, never come to know1? CHAP. XII. It is our intuitive and demonstrative knowledge of abstractions, not our concrete judgments of presumed pro babilities, that Locke has in view in this and the preceding section. CHAPTER XIII. SOME FURTHER CONSIDERATIONS CONCERNING OUR KNOWLEDGE. CHAP. Our XIII. 1. OUR knowledge, as in other things, so in this, has so BOOK IV. great a conformity with our sight, that it is neither wholly necessary, nor wholly voluntary1. If our knowledge were altogether necessary, all men's knowledge would not only be alike, but every man would know all that is knowable; and if Knowledge it were wholly voluntary, some men so little regard or value partly it, that they would have extreme little, or none at all. Men necessary, partly that have senses cannot choose but receive some ideas by voluntary. them; and if they have memory, they cannot but retain some of them; and if they have any distinguishing faculty, cannot but perceive the agreement or disagreement of some of them one with another; as he that has eyes, if he will open them by day, cannot but see some objects, and perceive a difference in them. But though a man with his eyes open in the light, cannot but see, yet there be certain objects which he may choose whether he will turn his eyes to; there may be in his reach a book containing pictures and discourses, capable to delight or instruct him, which yet he may never have the will to open, never take the pains to look into. 1 Absolute certainty is determined by necessity of reason. But although we are thus obliged to perceive it, when the relations which it involves are consciously realised by us, we are not in like manner obliged consciously to realise those relations. It is not necessary for each man actually to perceive all that, when perceived, must be seen by him to be intellectually neces- СНАР. XIII. BOOK IV. 2. There is also another thing in a man's power, and that is, though he turns his eyes sometimes towards an object, yet he may choose whether he will curiously survey The appli- it, and with an intent application endeavour to observe cation accurately all that is visible in it. But yet, what he does Faculties see, he cannot see otherwise than he does. It depends not voluntary; on his will to see that black which appears yellow; nor to being persuade himself, that what actually scalds him, feels cold. employed, The earth will not appear painted with flowers, nor the fields of our but, they we know are, not as as things covered with verdure, whenever he has a mind to it: in the we please. cold winter, he cannot help seeing it white and hoary, if he will look abroad. Just thus is it with our understanding: all that is voluntary in our knowledge is, the employing or withholding any of our faculties from this or that sort of objects, and a more or less accurate survey of them: but, they being employed1, our will hath no power to determine the knowledge of the mind one way or another; that is done only by the objects themselves, as far as they are clearly discovered. And therefore, as far as men's senses are conversant about external objects, the mind cannot but receive those ideas which are presented by them, and be informed of the existence of things without: and so far as men's thoughts converse with their own determined ideas, they cannot but in some measure observe the agreement or disagreement that is to be found amongst some of them, which is so far knowledge and if they have names for those ideas which they have thus considered, they must needs be assured of the truth of those propositions which express that agreement or disagreement they perceive in them, and be undoubtedly convinced of those truths. For what a man sees, he cannot but see; and what he perceives, he cannot but know that he perceives. Instance in Num bers. 3. Thus he that has got the ideas of numbers, and hath taken the pains to compare one, two, and three, to six, cannot choose but know that they are equal: he that hath got 1 He does not intend to say that what we are intellectually necessitated to know, and are thus under obligation to know, implies a purely passive per ception of what is thus known. Our intellect must be actively employed in the perception of the necessity. |