Having thus, from what our senses are able to discover in the operations of bodies on one another, got the notion of cause and effect, viz. that a cause is that which makes any other thing, either simple idea, substance, or mode, begin to be; and an effect is that which had its beginning from some other thing; the mind finds no great difficulty to distinguish the several originals of things into two sorts:— First, When the thing is wholly made new, so that no part thereof did ever exist before; as when a new particle of matter doth begin to exist, IN RERUM NATURA, which had before no being, and this we call CREATION. Secondly, When a thing is made up of particles, which did all of them before exist; but that very thing, so constituted of pre-existing particles, which, considered all together, make up such a collection of simple ideas, had not any existence before, as this man, this egg, rose, or cherry, &c. And this, when referred to a substance, produced in the ordinary course of nature by internal principle, but set on work by, and received from, some external agent, or cause, and working by insensible ways which we perceive not, we call GENERATION. When the cause is extrinsical, and the effect produced by a sensible separation, or juxta-position of discernible parts, we call it MAKING; and such are all artificial things. When any simple idea is produced, which was not in that subject before, we call it ALTERATION. Thus a man is generated, a picture made; and either of them altered, when any new sensible quality or simple idea is produced in either of them, which was not there before: and the things thus made to exist, which were not there before, are effects; and those things which operated to the existence, causes. In which, and all other cases, we may observe, that the notion of cause and effect has its rise from ideas received by sensation or reflection; and that this relation, how comprehensive soever, terminates at last in them. For to have the idea of cause and effect, it suffices to consider any simple idea or substance, as beginning to exist, by the operation of some other, without knowing the manner of that operation. 3. Relations of Time.