POWER being the source from whence all action proceeds, the substances wherein these powers are, when they *[lost line??] exert this power into act, are called CAUSES, and the substances which thereupon are produced, or the simple ideas which are introduced into any subject by the exerting of that power, are called EFFECTS. The EFFICACY whereby the new substance or idea is produced is called, in the subject exerting that power, ACTION; but in the subject wherein any simple idea is changed or produced, it is called PASSION: which efficacy, however various, and the effects almost infinite, yet we can, I think, conceive it, in intellectual agents, to be nothing else but modes of thinking and willing; in corporeal agents, nothing else but modifications of motion. I say I think we cannot conceive it to be any other but these two. For whatever sort of action besides these produces any effects, I confess myself to have no notion nor idea of; and so it is quite remote from my thoughts, apprehensions, and knowledge; and as much in the dark to me as five other senses, or as the ideas of colours to a blind man. And therefore many words which seem to express some action, signify nothing of the action or MODUS OPERANDI at all, but barely the effect, with some circumstances of the subject wrought on, or cause operating: v.g. CREATION, ANNIHILATION, contain in them no idea of the action or manner whereby they are produced, but barely of the cause, and the thing done. And when a countryman says the cold freezes water, though the word freezing seems to import some action, yet truly it signifies nothing but the effect, viz. that water that was before fluid is become hard and consistent, without containing any idea of the action whereby it is done. 12. Mixed Modes made also of other Ideas than those of Power and Action. I think I shall not need to remark here that, though power and action make the greatest part of mixed modes, marked by names, and familiar in the minds and mouths of men, yet other simple ideas, and their several combinations, are not excluded: much less, I think, will it be necessary for me to enumerate all the mixed modes which have been settled, with names to them. That would be to make a dictionary of the greatest part of the words made use of in divinity, ethics, law, and politics, and several other sciences. All that is requisite to my present design, is to show what sort of ideas those are which I call mixed modes; how the mind comes by them; and that they are compositions made up of simple ideas got from sensation and reflection; which I suppose I have done. CHAPTER XXIII. OF OUR COMPLEX IDEAS OF SUBSTANCES.