of them powers, in relation to changes, which they are apt to make in, or receive from other bodies, are almost infinite. He that shall but observe what a great variety of alterations any one of the baser metals is apt to receive from the different application only of fire; and how much a greater number of changes any of them will receive in the hands of a chymist, by the application of other bodies; will not think it strange that I count the properties of any sort of bodies not easy to be collected, and completely known by the ways of inquiry, which our faculties are capable of. They being therefore at least so many, that no man can know the precise and definite number, they are differently discovered by different men, according to their various skill, attention, and ways of handling; who therefore cannot choose but have different ideas of the same substance, and therefore make the signification of its common name very various and uncertain. For the complex ideas of substances being made up of such simple ones as are supposed to co-exist in nature, every one has a right to put into his complex idea those qualities he has found to be united together. For though in the substance of gold one satisfies himself with colour and weight, yet another thinks solubility in aq, regia as necessary to be joined with that colour in his idea of gold, as any one does its fusibility; solubility in aq. regia being a quality as constantly. joined with its colour and weight, as fusibility, or any other; others put into it ductility or fixedness, &c. as they have been taught by tradition or experience. Who of all these has established the right signification of the word gold? or who shall be the judge to determine? Each has its standard in nature, which he appeals to, and with reason thinks he has the same right to put into his complex idea, signified by the word gold, those qualities which upon trial he has found united; as another, who was not so well examined, has to leave them out; or a third, who has made other trials, has to put in others. For the union in nature of these qualities being the true ground of their union in one complex idea, who can say, one of them has more reason to be put in, or left out, than another? From hence it will 1 always always unavoidably follow, that the complex ideas of substances, in men using the same name for them, will be very various; and so the significations of those names very uncertain. isting qualities which are known but imperfectly. 3. To co-ex With this imperfection they may serve for civil, but not well for philosophical §. 14. Besides, there is scarce any particular thing existing, which, in some of its simple ideas, does not communicate with a greater, and in others a less number of particular beings: who shall determine in this case which are those that are to make up the precise collection that is to be signified by the specifick name; or can with any just authority prescribe, which obvious or common qualities are to be left out; or which more secret, or more particular, are to be put into the signification of the name of any substance? All which together seldom or never fail to produce that various and doubtful signification in the names of substances, which causes such uncertainty, disputes, or mistakes, when we come to a philosophical use of them. §. 15. It is true, as to civil and common conversation, the general names of substances, regulated in their ordinary signification by some obvious qualities, (as by the shape and figure in things of known seminal propagation, and in other substances, for the most part by colour, joined with some other sensible qualities) do well enough to design the things men would be understood to speak of: and so they usually conceive well enough the substances meant by the word gold, or apple, to distinguish the one from the other. But in philosophical inquiries and debates, where general truths are to be established, and consequences drawn from positions laid down; there the precise signification of the names of substances will be found, not only not to be well established, but also very hard to be so. For example, he that shall make malleableness, or a certain degree of fixedness, a part of his complex idea of gold, may make propositions concerning gold, and draw consequences from them, that will truly and clearly follow from gold, taken in such a signification: but yet such as another man can never be use. forced forced to admit, 'nor be convinced of their truth, who makes not malleableness, or the same degree of fixedness, part of that complex idea, that the name gold, in his use of it, stands for. Instance, liquor. §. 16. This is a natural, and almost unavoidable imperfection in almost all the names of substances, in all languages whatsoever which men will eafily find, when once passing from confused or loose notions, they come to more strict and close inquiries. For then they will be convinced how doubtful and obscure those words are in their signification, which in ordinary use appeared very clear and determined. I was once in a meeting of very learned and ingenious physicians, where by chance there arose a question, whether any liquor passed through the filaments of the nerves. The debate having been managed a good while, by variety of arguments on both sides, I (who had been used to suspect, that the greatest part of disputes was more about the signification of words than a real difference in the conception of things) desired, that before they went any farther on in this dispute, they would first examine, and establish amongst them, what the word liquor signified. They at first were a little surprised at the proposal; and had they been persons less ingenious, they might perhaps have taken it for a very frivolous or extravagant one: since there was no one there that thought not himself to understand very perfectly what the word liquor stood for; which I think too none of the most perplexed names of substances. However, they were pleased to comply with my motion, and upon examination found, that the signification of that word was not so settled and certain as they had all imagined; but that each of them made it a sign of a different complex idea. This made them perceive that the main of their dispute was about the signification of that term; and that they differed very little in their opinions, concerning some fluid and subtile matter, passing through the conduits of the nerves; though it was not so easy to agree whether it was to be called liquor or no, a thing which, when considered, they thought it not worth the contending about. §. 17. Instance, gold. §. 17. How much this is the case, in the greatest part of disputes that men are engaged so hotly in, I shall perhaps have an occasion in another place to take notice. Let us only here consider a little more exactly the fore-mentioned instance of the word gold, and we shall see how hard it is precisely to determine its signification. I think all agree to make it stand for a body of a certain yellow shining colour; which being the idea to which children. have annexed that name, the shining yellow part of a peacock's tail is properly to them gold. Others finding fusibility joined with that yellow colour in certain parcels of matter, make of that combination a complex idea, to which they give the name gold to denote a sort of substances; and so exclude from being gold all such yellow shining bodies, as by fire will be reduced to ashes; and admit to be of that species, or to be comprehended under that name gold, only such substances as having that shining yellow colour will by fire be reduced to fusion and not to ashes. Another by the same reason adds the weight, which being a quality, as straitly joined with that colour, as its fusibility, he thinks has the same reason to be joined in its idea, and to be signified by its name: and therefore the other made up of body, of such a colour and fusibility, to be imperfect; and so on of all the rest: wherein no one can show a reason why some of the inseparable qualities, that are always united in nature, should be put into the nominal essence, and others left out: or why the word gold, signifying that sort of body the ring on his finger is made of, should determine that sort rather by its colour, weight, and fusibility, than by its colour, weight, and solubility in aq. regia: since the dissolving it by that liquor is as inseparable from it as the fusion by fire; and they are both of them nothing but the relation which that substance has to two other bodies, which have a power to operate differently upon For by what right is it that fusibility comes to be a part of the essence signified by the word gold, and solubility but a property of it or why is its colour part of the essence, and its malleableness but a property? That which I mean is VOL. II. this, 4 this, That these being all but properties depending on its real constitution, and nothing but powers, either active or passive, in reference to other bodies: no one has authority to determine the signification of the word gold (as referred to such a body existing in nature) more to one collection of ideas to be found in that body than to another: whereby the signification of that name must unavoidably be very uncertain; since, as has been said, several people observe several properties in the same substance; and, I think, I may say no-body at all. And therefore we have but very imperfect descriptions of things, and words have very uncertain significations. The namesof simple ideas the least doubtful. §. 18. From what has been said, it is easy to observe what has been before remarked, viz. That the names of simple ideas are, of all others, the least liable to mistakes, and that for these reasons. First, because the ideas they stand for, being each but one single perception, are much easier got, and more clearly retained, than the more complex ones, and therefore are not liable to the uncertainty which usually attends those compounded ones of substances and mixed modes, in which the precise number of simple ideas, that make thein up, are not easily agreed, and so readily kept in the mind, And secondly, because they are never referred to any other essence, but barely that perception they immediately signify which reference is that which renders the signification of the names of substances naturally so perplexed, and gives occasion to so many disputes. Men that do not perversely use their words, or on purpose set themselves to cavil, seldom mistake in any language, which they are acquainted with, the use and signification of the names of simple ideas: white and sweet, yellow and bitter; carry a very obvious meaning with them, which every one precisely comprehends, or easily perceives he is ignorant of, and seeks to be informed. But what precise collection of simple ideas modesty or frugality stand for in another's use, is not so certainly know. And however we are apt to think we well enough know what is meant by gold or iron; yet the precise complex idea, others make them the signs of, |