If I have dwelt pretty long on the consideration of duration, space, and number, and what arises from the contemplation of them,—­Infinity, it is possibly no more than the matter requires; there being few simple ideas whose modes give more exercise to the thoughts of men than those do.  I pretend not to treat of them in their full latitude.  It suffices to my design to show how the mind receives them, such as they are, from sensation and reflection; and how even the idea we have of infinity, how remote soever it may seem to be from any object of sense, or operation of our mind, has, nevertheless, as all our other ideas, its original there.  Some mathematicians perhaps, of advanced speculations, may have other ways to introduce into their minds ideas of infinity.  But this hinders not but that they themselves, as well as all other men, got the first ideas which they had of infinity from sensation and reflection, in the method we have here set down.

CHAPTER XVIII.

Other simple modes.

1.  Other simple Modes of simple Ideas of sensation.

Though I have, in the foregoing chapters, shown how from simple ideas taken in by sensation, the mind comes to extend itself even to infinity; which, however it may of all others seem most remote from any sensible perception, yet at last hath nothing in it but what is made out of simple ideas:  received into the mind by the senses, and afterwards there put together, by the faculty the mind has to repeat its own ideas; —­Though, I say, these might be instances enough of simple modes of the simple ideas of sensation, and suffice to show how the mind comes by them, yet I shall, for method’s sake, though briefly, give an account of some few more, and then proceed to more complex ideas.

2.  Simple modes of motion.

To slide, roll, tumble, walk, creep, run, dance, leap, skip, and abundance of others that might be named, are words which are no sooner heard but every one who understands English has presently in his mind distinct ideas, which are all but the different modifications of motion.  Modes of motion answer those of extension; swift and slow are two different ideas of motion, the measures whereof are made of the distances of time and space put together; so they are complex ideas, comprehending time and space with motion.

3.  Modes of Sounds.

The like variety have we in sounds.  Every articulate word is a different modification of sound; by which we see that, from the sense of hearing, by such modifications, the mind may be furnished with distinct ideas, to almost an infinite number.  Sounds also, besides the distinct cries of birds and beasts, are modified by diversity of notes of different length put together, which make that complex idea called a tune, which a musician may have in his mind when he hears or makes no sound at all, by reflecting on the ideas of those sounds, so put together silently in his own fancy.