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this is but guelling still ; it amounts only to opinion, and has not that certainty which is requisite to know. ledge ; for all general knowledge lies only in our own thoughts, and consists barely in the contemplation of our own abstract ideas. Wherever we perceive any agreement or disagreement amongst them, there we have general knowledge ; and by putting the names of those ideas together accordingly in propofitions, can with certainty pronounce general trurbs. But because the abstract ideas of substances, for which their fpecific names stand, whenever they have any diftinct and determinate signification, have a discoverable connec. tion or inconsistency with but a very few other ideas; the certainty of universal propofitions concerning substances is very narrow and scanty in that part, which is our principal inquiry concerning them ; and there is scarce any of the names of substances, let the idea it is applied to be what it will, of which we can ge. nerally and with certainty pronounce, that it has or has not this or that other quality belonging to it, and constantly co-existing or inconsistent with that idea, wherever it is to be found. § i4. Il'hat is requisite for our Knowledge of Sub
sances. Before we can have any tolerable knowledge of this kind, we must first know what changes the primary qualities of one body do regularly produce in the prie mary qualities of another, and how. Secondly, We must know what primary qualities of any body produce certain sensations or ideas in us. This is in truth no less than to know all the effects of matter, under its divers modifications of bulk, figure, cohesion of parts, motion, and rest ; which, I think, every body will allow is utterly impoflible to be known by us with. out revelation ; nor, if it were revealed to us what sort of figure, bulk, and motion of corpuscles, would produce in us the sensation of a yellow colour, and what sort of figure, bulk, and texture of parts, in the superficies of any body, were fit to give such cor. puscles their due motion to produce that colour ; would that be enough to make universal propositions with certainty, concerning the several sorts of them, unless we had faculties acute enough to perceive the precise bulk, figure, texture, and motion of bodies in those minute parts, by which they operate on our senses, that so we might by those frame our abstract ideas of them. I have mentioned here only corporeal substances, whose operations seem to lie more level to our understandings ; for as to the operations of Spirits, both their thinking and moving of bodies, we at first fight find ourselves at a loss; though perhaps when we have applied our thoughts a little nearer to the consideration of bodies, and their operations, and examined how far our notions, even in these, reach, with any clearness, beyond sensible matter of fact, we shall be bound to confess, that even in these too our discoveries amount to very little beyond perfect igno. rance and incapacity. § 15. Whilst our Ideas of Substances contain not
their real Constitutions, we can make but few gee
neral certain Propositions concerning them. This is evident, the anstra&t complex ideas of substances, for which their general names stand, not comprehending their real constitutions, can afford us but very little univerfal certainty ; because our ideas of them are not made up of that, on which those qualities we observe in them, and would inform ourselves about, do depend, or with which they have any certain connection : v.g. Let the idea to which we give the name man, be, as it commonly is, a body of the ordinary shape, with sense, voluntary motion, and reason joined to it: This being the abstract idea, and consequently the essence of our species man, we can make but very few general certain propofitions concerning man, Itanding for such an idea ; because, not knowing the real constitution on which sensation, power of motion, and reasoning, with that peculiar shape, depend, and whereby they are united together in the same subject, there are very few other qualities, with which we can perceive them to have a necessary connexion ; and therefore we can
not with certainty affirm, that all men sleep by intervals; that no man can be nourished by word or Jones ; that all nen will be poifined by bemlock; because these i:leas have no connection nor repugnancy with this our nominal essence of man, with this al. stract idea that name stands for. We must in these and the like appeal to trial in particular subjects, which can reach but a little way; we must content ourselves with probability in the rest, but can have no general certainty, whilst our specific idea of man contains not that real constitution, which is the root, wherein all his inseparable qualities are united, and from whence they flow. Whilft our idéa, the word man stands for, is only an imperfect collection of fome sensible qualities and powers in him, there is no difcernible connection or repugnance between our specific idea, and the operation of either the parts of hemlock or stones upon his constitution. There are animals that safely eat hemlock, and others that are nourished by wood and stones : But as long as we want ideas of those real constitutions of different forts of animals, whereon these and the like qualities and powers depend, we must not hope to reach certainty in universal propositions concerning them. Those few ideas only which have a discernible connection with our nominal eilence, or any part of it, can afford us such propofitions; but these are so few, and of so little moment, that we may jufly look on our certain general knowledge of substances as almost none at all. Š 16. Wherein lies the general Certainty of Pro.
positions. To conclude, general prop:sitions, of what kind so. ever, are then only capable of certainty, when the terms used in them stand for such ideas, whose agree. ment or disagreement, as there expreiled, is capable to be discovered by us; and we are then certain of their truth or falsehood, when we perceive the ideas the terms stand for, to agree or not agree, according as they are affirmed or denied one of another ; whence we may take notice, that general certainty is never to
. be found but in our ideas. Whenever we go to seek it elsewhere in experiment, or observations with out us, our knowledge goes not beyond particulars. It is the contemplation of our own abstract ideas that alone is able to afford us general knowledge.
1. They are self-evident. THERE are a sort of propositions, which under
I the name of maxims and axioms have passed for principles of science; and because they are felf-evident, have been supposed innate, although nobody (that I know ever went about to fhow the reason and foundation of their clearnels or cogency, It may however be worth while to inquire into the reason of their evidence, and see whether it be peculiar to them alone, and also examine how far they influence and govern our other knowledge.
§ 2. Wherein that Self-evidence consists. KNOWLEDGB, as has been shown, conlills in the perception of the agreement or dilagreement of ideas : Now where that agreement or dilagreement is perceived immediately by itself, without the intervention or help of any other, there our knowledge is felf-evident. This will appear to be so to any one who will but consider any of those propositions, which, without any proof, he allents to at first light ; for in all of them he will find, that the reason of his. affint is from that agreement or disagreenient which the mind, by an immediaie comparing them, finds in those ideas answering the affirmation or negation in the proposition. . $ 3. Self-evidence not peculiar to received Axiom:. This being so, in the next place let us contider, whether this self-evidence be peculiar only to those propotitions, which commonly pass under the name of maxims, and have the dignity of axioms allowed them. And here it is plain, that several other truths, not allowed to be axioms, partake equally with them in this felf-evilence. This we thall fee, if we go over these several sorts of agreement or disagreement of ideas, which I have above mentioned, viz. identity relation, co-existence, and real existence ; which will discover to us, that not only those few propofitions, which have had the credit of maxims, are self-evi. dent, but a great many, even almost an infinite num. ber of ot ber propofitions, are such. § 4. 1. As to Identity ad Diversity, all Propofitions
are equally self-evident. For, first, the immediate perception of the agreement or disagreement of identity being founded in the mind's having distinct ideas, this affords us as many self-evi. dent propofitions as we have diftinet ideas. Every. one that has any knowledge at all, has, as the foun. dation of it, various and distinct ideas ; and it is the first act of the mind (without which it can never be capable of any knowledge) to know every one of its ideas by itself, and distinguish it from others. Every one finds in himself, that he knows the ideas he has ; that he knows also, when any one is in his understanding, and what it is ; and that when more than one are there, he knows them distinctly and 18confusedly one from another ; which always being so (it being imposlible but that he should perceive what he perceives), he can never be in doubt when any idea is in his mind, that it is there, and is that idea it is; and that two distinct ideas, when they are in his mind, are there, and are not one and the same idea. So that all such affirmations and negations are made without any possibility of doubt, uncertainty or hefitation, and mult necessarily be assented to as soon as understood ; that is, as soon as we have in our minds determined id:as, which the terms in the proposition stand for ; and therefore wherever the mind with attention considers any proposition, so as to perceive the two ideas fignified by the terms, and affirm