I start with a notorious argument of Berkeley's.

1. Phil. But (to pass by all that hath been hitherto said, and reckon it for nothing, if you will have it so) I am content to put the whole upon this issue. If you can conceive it possible for any mixture or combination of qualities, or any sensible object whatever, to exist without the mind, then I will grant it actually to be so.

2. Hyl. If it comes to that, the point will soon be decided. What more easy than to conceive a tree or house existing by itself, independent of, and unperceived by any mind whatsoever? I do at this present time conceive them existing after that manner.

3. Phil. How say you, Hylas, can you see a thing which is at the same time unseen?

4. Hyl. No, that were a contradiction.

5. Phil. Is it not a contradiction to talk of conceiving a thing which is unconccived?

6. Hyl. It is.

7. Phil. The tree or house therefore which you think of, is conceived by you.

8. Hyl. How should it be otherwise?

9. Phil. And what is conceived is surely in the mind.

10. Hyl. Without question, that which is conceived is in the mind.

11. Phil. How then came you to say, you conceived a house or tree existing independent and out of all minds whatsoever?

12. […]