First, when the mind supposes any idea it has CONFORMABLE to that in OTHER MEN’S MINDS, called by the same common name; v.g. when the mind intends or judges its ideas of justice, temperance, religion, to be the same with what other men give those names to.
Secondly, when the mind supposes any idea it has in itself to be CONFORMABLE to some REAL EXISTENCE. Thus the two ideas of a man and a centaur, supposed to be the ideas of real substances, are the one true and the other false; the one having a conformity to what has really existed, the other not. Thirdly, when the mind REFERS any of its ideas to that REAL constitution and ESSENCE of anything, whereon all its properties depend: and thus the greatest part, if not all our ideas of substances, are false.
6. The cause of such Reference.
These suppositions the mind is very apt tacitly to make concerning its own ideas. But yet, if we will examine it, we shall find it is chiefly, if not only, concerning its ABSTRACT complex ideas. For the natural tendency of the mind being towards knowledge; and finding that, if it should proceed by and dwell upon only particular things, its progress would be very slow, and its work endless; therefore, to shorten its way to knowledge, and make each perception more comprehensive, the first thing it does, as the foundation of the easier enlarging its knowledge, either by contemplation of the things themselves that it would know, or conference with others about them, is to bind them into bundles, and rank them so into sorts, that what knowledge it gets of any of them it may thereby with assurance extend to all of that sort; and so advance by larger steps in that which is its great business, knowledge. This, as I have elsewhere shown, is the reason why we collect things under comprehensive ideas, with names annexed to them, into genera and species; i.e. into kinds and sorts.
7. Names of things supposed to carry in them knowledge of their essences.
If therefore we will warily attend to the motions of the mind, and observe what course it usually takes in its way to knowledge, we shall I think find, that the mind having got an idea which it thinks it may have use of either in contemplation or discourse, the first thing it does is to abstract it, and then get a name to it; and so lay it up in its storehouse, the memory, as containing the essence of a sort of things, of which that name is always to be the mark. Hence it is, that we may often observe that, when any one sees a new thing of a kind that he knows not, he presently asks, what it is; meaning by that inquiry nothing but the name. As if the name carried with it the knowledge of the species, or the essence of it; whereof it is indeed used as the mark, and is generally supposed annexed to it.
8. How men suppose that their ideas must correspond to things, and to the customary meanings of names.
But this ABSTRACT IDEA, being something in the mind, between the thing that exists, and the name that is given to it; it is in our ideas that both the rightness of our knowledge, and the propriety and intelligibleness of our speaking, consists. And hence it is that men are so forward to suppose, that the abstract ideas they have in their minds are such as agree to the things existing without them, to which they are referred; and are the same also to which the names they give them do by the use and propriety of that language belong. For without this double conformity of their ideas, they find they should both think amiss of things in themselves, and talk of them unintelligibly to others.
9. Simple Ideas may be false, in reference to others of the same Name, but are least liable to be so.
First, then, I say, that when the truth of our ideas is judged of by the conformity they have to the ideas which other men have, and commonly signify by the same name, they may be any of them false. But yet SIMPLE IDEAS are least of all liable to be so mistaken. Because a man, by his senses and every day’s observation, may easily satisfy himself what the simple ideas are which their several names that are in common use stand for; they being but few in number, and such as, if he doubts or mistakes in, he may easily rectify by the objects they are to be found in. Therefore it is seldom that any one mistakes in his names of simple ideas, or applies the name red to the idea green, or the name sweet to the idea bitter: much less are men apt to confound the names of ideas belonging to different senses, and call a colour by the name of a taste, &c. Whereby it is evident that the simple ideas they call by any name are commonly the same that others have and mean when they use the same names.