I shall therefore pass over that chimerical supposition, and consider them as collections of simple ideas in the mind, taken from combinations of simple ideas existing together constantly in things, of which patterns they are the supposed copies; and in this reference of them to the existence of things, they are false ideas: When they put together simple ideas, which in the real existence of things have no union; as when to the shape and size that exist together in a horse, is joined in the same complex idea the power of barking like a dog: which three ideas, however put together into one in the mind, were never united in nature; and this, therefore, may be called a false idea of a horse.