qualities, we can go but a very little way in; and in all their secondary qualities, we can discover no connexion dat all, for the reasons mentioned, chap. iii.viz?41. Bebeause we know not the real constitutions of substances, on which each secondary quality particularly depends. 12. Did we know that, it would serve us only for experimental (not universal) knowledge; and reach with certainty no farther, than that bare instance, because our understandings can discover no conceivable connexion between any secondary quality and any modification whatsoever of any of the primary ones. And therefore there are very few general propositions to be made concerning substances, which can carry with them undoubted certainty, or add rose le doveq todo ni Slug, sAll gold is fixed, is a proposition los jug whose truth we cannot be certain of, showInstance in gold. universally soever it be believed. For if, ud of el according to the useless imagination of the schools, any one supposes the term gold to stand for a species of things set out by nature, by a real essence belonging to lit, it is evident he knows not what particular substances are of that species: and so cannot, with certainty, affirm any thing universally of gold. But if he makes gold stand for a species determined by its nominal essence, Slet the m nominal essence, for example, be the complex idea of a body of a certain yellow colour malleable, fusible, and heavier than any other known in this proper use of the d gold, there is no difficulty to know what is or is not gold. But yet no other quality can with certainty be universally affirmed or denied of gold, but what hath a discoverable connexion or inconsistency with that nominal essence. Fixedness, for example, having no necessary connexion, that we cau discover, with the colour, weight, or any other simples idea of our complex one, or with the whole combination toge ther it is impossible that we should certainly know the Struth of this proposition, that all gold is fixed.

RUOWD

m. 9. As there is no discoverable connexion between fixedness and the colour, weight, and other simple ideas of that nominal essence of gold; so if we make our complex idea of gold a body yellow, fusible, ductile, weighty,

and fixed, we shall be at the same uncertainty concerning solubility in aq. regia, and for the same reason: since we can never, from consideration of the ideas themselves, with certainty affirm or deny of a body, For whose complex idea is made up of yellow, very weighty, ductile, and fixed, it is aqua Jusible, a soluble in regia; and so on, of the rest of its qualities, I gladly meet with one general affirmation concerning any quality of gold, that any one can certainly know is true. As It will, no doubt, be presently objected, is not this an universal proposition, "all gold is malleable?" To which I answer, it is a very certain proposition, if malleableness be a part of the complex idea the word gold stands for. But then here is nothing affirmed of gold, but that that sound stands for an idea in which mallealeness is contained and such a sort of truth and cer tainty as this, it is to say a centaur is four-footed. But if malleableness makes not a part of the specific essence the name of gold stands for, it is plain, "all golu is malleable is not a certain proposition. Because let the complex idea of gold be made up of which soever of its other qualities you please, malleableness will not ap pear too to depend on that complex idea, nor follow from any simple one contained in it: the connexion that malleableness has (if it has any) with those other quali ties, being only by the intervention of the real constitution of its insensible parts; which, since we know not, it is impossible we should perceive that connexion, unless we could discover that which ties them together, As far as any §. 10. The more, indeed, of these cosuch coexist- existing qualities we unite one complex ence can be idea, under one name, the more precise and known, so far determinate we make the,, signification of that word; but never yet make it thereby more capable of universal certainty, in respect of other qualities not contained in our complex idea; since we perceive not their connexion or dependence on one another, being ignorant both of that real constitution in which they are all founded, and also how they flow from it. For the chief part of our knowledge cons

universal propositions may be certain. But this will go

but a little

way, because

Into

more

cerning substances is not, as in other things, barely of the relation of two ideas that may exist separately; but is of the necessary connexion and co-existence of several distinct ideas in the same subject, or of their repugnancy For so to co-exist. Could we begin at the other end, and discover what it was, wherein that colour consisted, what made a body lighter or heavier, what texture of parts made it malleable, fusible, and fixed, and fit to be dissolved in this sort of liquor, and not in another; if (I say) we had such an idea as this of bodies, and could perceive wherein all sensible qualities originally consist, and how they are produced; we might frame such ideas of them, as would furnish us with matter of more general knowledge, and enable us to make universal propositions, that should carry general truth and certainty with them. But whilst our complex ideas of the sorts of substances are so remote from that internal real con stitution, on which their sensible qualities depend, and are made up of nothing but an imperfect collection of those apparent qualities our senses can discover; there can be few general propositions concerning substances, of whose real truth we can be certainly assured: sinte there are but few simple ideas, of whose connexion and necessary co-existence we can have certain and undoubted knowledge. I imagine, amongst all the secondary qualities of substances, and the powers relating to them, there cannot any two be named, whose necessary co-existence, or repugnance to co-exist, can certainly be known, unless in those of the same sense, which necessarily exclude one another, as I have elsewhere showed.. No one, I think, by the colour that is in any body, can certainly know what smell, taste, sound, or tangible qualities it has, nor what alterations it is capable to make or receive, on of from other bodies. The same may be said of the Sound or taste, &c. Our specific names standing for any collections of such ideas, it is not to be wondered, that we can with them make very few general propositions of undoubted real certainty. But yet so far as any complex idea, of any sort of substances, contains in it any simple idea, whose necessary co-existence with any other may be discovered,

of substancesuc

stances, de

causes.

pro

so far universal propositions may with certainty be made concerning its g, could any one discover a necessary connexion between malleableness, and the colour or weight of gold, or any other part of the complex idea sigl nified by that name, he might make a certain universal proposition concerning gold in this respect; and the real truth of this proposition, that all gold is malleables”? would be as certain as of this, "the three angles of all right-lined triangles are all equal to two right ones."d Thequalities§ 11. Had we such ideas of substances, which make as to know what real constitutions produce our complex those sensible qualities we find in them, and ideas of sub- how those qualities flowed from thence, we pend mostly could, by the specific ideas of their real on external, essences in our own minds, more certainly remote, and find out their properties, and discover what unperceived qualities they had or had not, than we can 2stood alonow by our senses and to know the perties of gold, it would be no more necessary that gold should exist, and that we should make experiments upon it, than it is necessary for the knowing the properties of a triangle, thats a triangle should exist in any matter, the idea in our minds would serve for the one as well as the other. noBut we are so far from being admitted into the secrets of nature, that we scarce so much as ever approach the first entrance towards them. For we are wont to consider the substances we meet with, each of them as an entire thing by itself, having all its qualities in itself, and independent of other things; overlooking, for the most part, the operations of those invisible nuids' they are encompassed with, and upon whose motions and operations depend the greatest part of those quali ties which are taken notice of in them, and are made by! us the inherent marks of distinction whereby we know and denominates them. Put a piece of gold anywhere by itself, separate from the reach and influence of allo® other bodies, it will immediately lose all its colour and weight, and perhaps malleableness too; which, for aught I I know, would be changed into a perfect friability, Water, in which to us fluidity is an essential quality left to itself, would cease to be fluid. But if inanimate

bodies owe so much of their present state to other bodies without them, that they would not be what they appear to us, were those bodies that environ them removed; it is yet more so in vegetables, which are nourished!! grow, and produce leaves, flowers, and seeds, in alcoho stant succession. And if we look a little nearer into the state of animals, we shall find that their dependence, as to life, motion, and the most considerable qualities to be observed in them, is so wholly on extrinsical causes and qualities of other bodies that make no part of them, that they cannot subsist a moment without them: though yet those bodies on which they depend, are little taken notice of, and make no part of the complex ideas we frame of those animals. Take the air but for a minute from the greatest part of living creatures, and they pre sently lose sense, life, and motion: This the necessity of breathing has forced into our knowledge. But how many other extrinsical, and possibly very remote bodies, do the springs of these admirable machines depend) on, which are not vulgarly observed, om so much as thought on, and how many are there, which the severesti inquiry can never discover? The inhabitants of this spot of the universe, though removed so many millions of miles from the sun, yet depend so much on the duly tempered motion of particles coming from, or agitated by it, that were this earth removed but a small part of the distance out of its present situation, and plated car little farther or nearer that source of heat, it is more than probable that the greatest part of the animals in it would immediately perish. since we find them so often) destroyed by an excess or defect of the sun's warmth, which, an accidental position, in some parts of this durs little globe, exposes them to. The qualities observed in a loadstone must needs have their source far beyond the confines of that body; and the ravage made often on several sorts of animals by invisible causes, the cered tain death (as we are told) of some of them, by barelyo passing the line, or, as it is certain of other, by being removed into a neighbouring country; evidently show! that the concurrence and operations of several bodies!! with which they are seldom thought to have any things.