Again there is a very remarkable passage in Section 10, of the fourth Dialogue of Berkeley’s Alciphron. I have already quoted it, at greater length, in my Principles of Natural Knowledge:
“Euphranor. Tell me, Alciphron, can you discern the doors, window and battlements of that same castle?
Alciphron. I cannot. At this distance it seems only a small round tower.
Euph. But I, who have been at it, know that it is no small round tower, but a large square building with battlements and turrets, which it seems you do not see.
Alc. What will you infer from thence?
Euph. I would infer that the very object which you strictly and properly perceive by sight is not that thing which is several miles distant.
Alc. Why so?
Euph. Because a little round object is one thing, and a great square object is another. Is it not so?...”
Some analogous examples concerning a planet and a cloud are then cited in the dialogue, and this passage finally concludes with:
“Euphranor. Is it not plain, therefore, that neither the castle, the planet, nor the cloud, which you see here, are those real ones which you suppose exist at a distance?”