But as the mind is wholly passive in the reception of all its simple ideas, so it exerts several acts of its own, whereby out of its simple ideas, as the materials and foundations of the rest, the others are framed. This shows man's power, and its ways of operation, to be much the same in the material and intellectual world. For the materials in both being such as he has no power over, either to make or destroy, all that man can do is either to unite them together, or to set them by one another, or wholly separate them. I shall here begin with the first of these in the consideration of complex ideas, and come to the other two in their due places. For simple ideas are all from things themselves, and of these the mind can have no more, nor other than what are suggested to it.
Complex ideas are either of modes, substances, or relations.
Ideas of modes. Simple and mixed modes of simple ideas. I call simple modes as being contained within the bounds of one simple idea. Ideas of substances, single or collective. Ideas of relation.