First, MODES I call such complex ideas which, however compounded, contain not in them the supposition of subsisting by themselves, but are considered as dependences on, or affections of substances;—such as are the ideas signified by the words triangle, gratitude, murder, &c. And if in this I use the word mode in somewhat a different sense from its ordinary signification, I beg pardon; it being unavoidable in discourses, differing from the ordinary received notions, either to make new words, or to use old words in somewhat a new signification; the later whereof, in our present case, is perhaps the more tolerable of the two.
5. Simple and mixed Modes of Ideas.
Of these MODES, there are two sorts which deserve distinct consideration:—
First, there are some which are only variations, or different combinations of the same simple idea, without the mixture of any other;—as a dozen, or score; which are nothing but the ideas of so many distinct units added together, and these I call SIMPLE MODES as being contained within the bounds of one simple idea.
Secondly, there are others compounded of simple ideas of several kinds, put together to make one complex one;—v.g. beauty, consisting of a certain composition of colour and figure, causing delight to the beholder; theft, which being the concealed change of the possession of anything, without the consent of the proprietor, contains, as is visible, a combination of several ideas of several kinds: and these I call MIXED MODES.
6. Ideas of Substances, single or collective.
Secondly, the ideas of SUBSTANCES are such combinations of simple ideas as are taken to represent distinct PARTICULAR things subsisting by themselves; in which the supposed or confused idea of substance, such as it is, is always the first and chief. Thus if to substance be joined the simple idea of a certain dull whitish colour, with certain degrees of weight, hardness, ductility, and fusibility, we have the idea of lead; and a combination of the ideas of a certain sort of figure, with the powers of motion, thought and reasoning, joined to substance, make the ordinary idea of a man. Now of substances also, there are two sorts of ideas:—one of SINGLE substances, as they exist separately, as of a man or a sheep; the other of several of those put together, as an army of men, or flock of sheep—which COLLECTIVE ideas of several substances thus put together are as much each of them one single idea as that of a man or an unit.
7. Ideas of Relation.
Thirdly, the last sort of complex ideas is that we call RELATION, which consists in the consideration and comparing one idea with another.
Of these several kinds we shall treat in their order.