I cannot quit the subject of identity, however,--though from my belief of its importance, I may already, perhaps, have dwelt upon it too long,--without giving you some slight account of the very strange opinions of Mr Locke on the subject. I do this, both because some notice is due, to the paradoxes,--even though they be erroneous,--of so illustrious a man, and because I conceive it to be of great advantage, to point out to you occasionally the illusions, which have been able to obscure the discernment of those _bright_ spirits, which nature sometimes, though sparingly, grants, to adorn at least that intellectual gloom, which even they cannot irradiate; that, in their path of glory, seem to move along the heavens by their own independent light, as if almost unconscious of the darkness below, but cannot exist there for a moment, without shedding, on the feeble and doubtful throngs beneath, some faint beams of their own incommunicable lustre. It is chiefly, as connected with these eminent names, that fallacy itself becomes instructive, when simply exhibited,--if this only be done, not from any wish to disparage merits, that are far above the impotence of such attempts, but with all the veneration which is due to human excellence, united as it must ever be to human imperfection, “Even the errors of great men,” it has been said, “are fruitful of truths;” and, though they were to be attended with no other advantage, this one at least they must always have, that they teach us how very possible it is for man to err; thus lessening at once our tendency to slavish acquiescence in the unexamined opinions of others, and--which is much harder to be done--lessening also, as much as it is possible for any thing to lessen, the strong conviction, which we feel, that we are ourselves unerring.--The first and most instructive lesson, which man can receive, when he is capable of reflection, is to _think for himself_; the second, without which the first would be comparatively of little value, is to reject, in _himself_, that infallibility, which he rejects in _others_.