Three Dialogues Between Hylas and Philonous

by George Berkeley

when men of less leisure see them who are supposed to have spent their whole time in the pursuits of knowledge professing an entire ignorance of all things, or advancing such notions as are repugnant to plain and commonly received principles, they will be tempted to entertain suspicions concerning the most important truths, which they had hitherto held sacred and unquestionable.

since this revolt from metaphysical notions to the plain dictates of nature and common sense, I find my understanding strangely enlightened, so that I can now easily comprehend a great many things which before were all mystery and riddle.

PHIL. Suppose now one of your hands hot, and the other cold, and that they are both at once put into the same vessel of water, in an intermediate state; will not the water seem cold to one hand, and warm to the other? HYL. It will. PHIL. Ought we not therefore, by your principles, to conclude it is really both cold and warm at the same time, that is, according to your own concession, to believe an absurdity? HYL. I confess it seems so.

The famous bucket of water example.

PHIL. And those, I suppose, are to be thought real which are discovered by the most near and exact survey. HYL. Right. PHIL. Is the nearest and exactest survey made by the help of a microscope, or by the naked eye? HYL. By a microscope, doubtless. PHIL. But a microscope often discovers colours in an object different from those perceived by the unassisted sight. And, in case we had microscopes magnifying to any assigned degree, it is certain that no object whatsoever, viewed through them, would appear in the same colour which it exhibits

Again, he's expecting me to rely upon my intuitive implicit acceptance of real, corporeal substance (which can be examined in a microscope), in order to make his point about the distinction between real and apparent properties. But to do this, is to surrender his original project, of proving that there is no such thing as corporeal substance that exists beyond what is experienced in the mind as perception.

PHIL. Now, is it not plain that if we suppose a man born blind was on a sudden made to see, he could at first have no experience of what may be SUGGESTED by sight?

The famous blind man case