them, by certain obvious appearances, into species, that we may the easier under general names communicate our thoughts about them.  For, having no other knowledge of any substance but of the simple ideas that are united in it; and observing several particular things to agree with others in several of those simple ideas; we make that collection our specific idea, and give it a general name; that in recording our thoughts, and in our discourse with others, we may in one short word designate all the individuals that agree in that complex idea, without enumerating the simple ideas that make it up; and so not waste our time and breath in tedious descriptions:  which we see they are fain to do who would discourse of any new sort of things they have not yet a name for.

31.  Essences of Species under the same Name very different in different minds.

But however these species of substances pass well enough in ordinary conversation, it is plain that this complex idea wherein they observe several individuals to agree, is by different men made very differently; by some more, and others less accurately.  In some, this complex idea contains a greater, and in others a smaller number of qualities; and so is apparently such as the mind makes it.  The yellow shining colour makes gold to children; others add weight, malleableness, and fusibility; and others yet other qualities, which they find joined with that yellow colour, as constantly as its weight and fusibility.  For in all these and the like qualities, one has as good a right to be put into the complex idea of that substance wherein they are all joined as another.  And therefore different men, leaving out or putting in several simple ideas which others do not, according to their various examination, skill, or observation of that subject, have different essences of gold, which must therefore be of their own and not of nature’s making.

32.  The more general our Ideas of Substances are, the more incomplete and partial they are.

If the number of simple ideas that make the nominal essence of the lowest species, or first sorting, of individuals, depends on the mind of man, variously collecting them, it is much more evident that they do so in the more comprehensive classes, which, by the masters of logic, are called genera.  These are complex ideas designedly imperfect:  and it is visible at first sight, that several of those qualities that are to be found in the things themselves are purposely left out of generical ideas.  For, as the mind, to make general ideas comprehending several particulars, leaves out those of time and place, and such other, that make them incommunicable to more than one individual; so to make other yet more general ideas, that may comprehend different sorts, it leaves out those qualities that distinguish them, and puts into its new collection only such ideas as are common to several sorts.  The same convenience that made men express several parcels of yellow matter coming