The mind of man is the noblest work of God which reason discovers to us, and therefore, on account of its dignity, deserves our study. It must, indeed, be acknowledged, that although it is of all objects the nearest to us, and seems the most within our reach, it is very difficult to attend to its operations, so as to form a distinct notion of them; and on that account there is no branch of knowledge in which the ingenious and speculative have fallen into so great errors, and even absurdities. These errors and absurdities have given rise to a general prejudice against all inquiries of this nature; and because ingenious men have, for many ages, given different and contradictory accounts of the powers of the mind, it is concluded that all speculations concerning them are chimerical and visionary. But whatever effect this prejudice may have with superficial thinkers, the judicious will not be apt to be carried away with it.