I see this cherry, I feel it, I taste it: and I am sure nothing cannot be seen, or felt, or tasted: it is therefore real. Take away the sensations of softness, moisture, redness, tartness, and you take away the cherry, since it is not a being distinct from sensations. A cherry, I say, is nothing but a congeries of sensible impressions, or ideas perceived by various senses: which ideas are united into one thing (or have one name given them) by the mind, because they are observed to attend each other. Thus, when the palate is affected with such a particular taste, the sight is affected with a red colour, the touch with roundness, softness, &c. Hence, when I see, and feel, and taste, in such sundry certain manners, I am sure the cherry exists, or is real; its reality being in my opinion nothing abstracted from those sensations. But if by the word cherry you mean an unknown nature, distinct from all those sensible qualities, and by its existence something distinct from its being perceived; then, indeed, I own, neither you nor I, nor any one else, can be sure it exists.
George Berkeley Three Dialogues Between Hylas And Philonous