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. XIII. Our 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 Know. ledge 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- XIII. of our but, they we know are, not as BOOK IV. 2. There is also another thing in a man's power, and that is, though he turns his eyes sometimes towards an СНАР. 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 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 employed', 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. СНАР. the idea of a triangle, and found the ways to measure its BOOK IV. angles and their magnitudes, is certain that its three angles are equal to two right ones; and can as little doubt of that, as of this truth, that, It is impossible for the same thing to be, and not to be. XIII. in Natural 4. He also that hath the idea of an intelligent, but frail Instance and weak being, made by and depending on another, who is Religion. eternal, omnipotent, perfectly wise and good, will as certainly know that man is to honour, fear, and obey God, as that the sun shines when he sees it. For if he hath but the ideas of two such beings in his mind, and will turn his thoughts that way, and consider them, he will as certainly find that the inferior, finite, and dependent, is under an obligation to obey the supreme and infinite, as he is certain to find that three, four, and seven are less than fifteen; if he will consider and compute those numbers: nor can he be surer in a clear morning that the sun is risen; if he will but open his eyes, and turn them that way. But yet these truths, being ever so certain, ever so clear, he may be ignorant of either, or all of them, who will never take the pains to employ his faculties, as he should, to inform himself about them 1. 1 The touchstone of science is the universal validity of its results for all normally constituted and duly instructed minds.' (Pearson's Grammar of Science, p. 30.) The touchstone of metaphysical or theological truth in like manner presupposes due instruc- BOOK IV. - СНАР. Our Know ledge being CHAPTER XIV. OF JUDGMENT1. 1. THE understanding faculties being given to man, not barely for speculation, but also for the conduct of his life, man would be at a great loss if he had nothing to direct him but what has the certainty of true knowledge. For that being very short and scanty, as we have seen, he would be often utterly in the dark, and in most of the actions of his life, short, we perfectly at a stand, had he nothing to guide him in the something absence of clear and certain knowledge. He that will not eat till he has demonstration that it will nourish him; he that will not stir till he infallibly knows the business he goes about will succeed, will have little else to do but to sit still and perish. want else. What this State. 2. Therefore, as God has set some things in broad daylight; as he has given us some certain knowledge, though limited to a few things in comparison, probably as a taste of what intellectual creatures are capable of to excite in us a desire and endeavour after a better state: so, in the greatest part of our concernments, he has afforded us only the twilight, as I may so say, of probability; suitable, I presume, to that state of mediocrity and probationership he has been pleased to place us in here; wherein, to check our over-confidence and presumption, we might, by every day's experience, be made 'Locke's restricted application of the term 'judgment,' which he opposes to 'knowledge,' has been already noted. In the more usual meaning of judgment, every affirmation and negation, certain or probable, is so named. Locke limits 'judgment' to (more or less) probable assertions in contrast to the self-evident and demonstrated ones which constitute knowledge proper, or absolute certainty. |