impossible, may any one say, for a man to think long of any one thing. By which, if it be meant that a man may have one self-same single idea a long time alone in his mind, without any variation at all, I think, in matter of fact, it is not possible. For which (not knowing how the ideas of our minds are framed, of what materials they are made, whence they have their light, and how they come to make their appearances) I can give no other reason but experience: and I would have any one try, whether he can keep one unvaried single idea in his mind, without any other, for any considerable time together.
- Proof.
For trial, let him take any figure, any degree of light or whiteness, or what other he pleases, and he will, I suppose, find it difficult to keep all other ideas out of his mind; but that some, either of another kind, or various considerations of that idea, (each of which considerations is a new idea,) will constantly succeed one another in his thoughts, let him be as wary as he can.
- The extent of our power over the succession of our ideas.
All that is in a man’s power in this case, I think, is only to mind and observe what the ideas are that take their turns in his understanding; or else to direct the sort, and call in such as he hath a desire or use of: but hinder the constant succession of fresh ones, I think he cannot, though he may commonly choose whether he will heedfully observe and consider them.
- Ideas, however made, include no sense of motion.
Whether these several ideas in a man’s mind be made by certain motions, I will not here dispute; but this I am sure, that they include no idea of motion in their appearance; and if a man had not the idea of motion otherwise, I think he would have none at all, which is enough to my