light is, the more discernible is the shadow) does not, when a man looks on it, cause as clear and positive idea in his mind, as a man himself, though covered over with clear sunshine? And the picture of a shadow is a positive thing. Indeed, we have negative names, to which there be no positive ideas; but they consist wholly in negation of some certain ideas, as SILENCE, INVISIBLE; but these signify not any ideas in the mind but their absence.
- Whether any ideas are due to causes really private.
And thus one may truly be said to see darkness. For, supposing a hole perfectly dark, from whence no light is reflected, it is certain one may see the figure of it, or it may be painted; or whether the ink I write with makes any other idea, is a question. The privative causes I have here assigned of positive ideas are according to the common opinion; but, in truth, it will be hard to determine whether there be really any ideas from a privative cause, till it be determined, whether rest be any more a privation than motion.
- Ideas in the Mind, Qualities in Bodies.
To discover the nature of our IDEAS the better, and to discourse of them intelligibly, it will be convenient to distinguish them AS THEY ARE IDEAS OR PERCEPTIONS IN OUR MINDS; and AS THEY ARE MODIFICATIONS OF MATTER IN THE BODIES THAT CAUSE SUCH PERCEPTIONS IN US: that so we may not think (as perhaps usually is done) that they are exactly the images and resemblances of something inherent in the subject; most of those of sensation being in the mind no more the likeness of something existing without us, than the names that stand for them are the likeness of our ideas, which yet upon hearing they are apt to excite in us.
- Our Ideas and the Qualities of Bodies.