Bayle.—­No; the more profound our searches are into the nature of things, the more uncertainty we shall find; and the most subtle minds see objections and difficulties in every system which are overlooked or undiscoverable by ordinary understandings.

Locke.—­It would be better, then, to be no philosopher, and to continue in the vulgar herd of mankind, that one may have the convenience of thinking that one knows something.  I find that the eyes which Nature has given me see many things very clearly, though some are out of their reach, or discerned but dimly.  What opinion ought I to have of a physician who should offer me an eye-water, the use of which would at first so sharpen my sight as to carry it farther than ordinary vision, but would in the end put them out?  Your philosophy, Monsieur Bayle, is to the eyes of the mind what I have supposed the doctor’s nostrum to be to those of the body.  It actually brought your own excellent understanding, which was by nature quick-sighted, and rendered more so by art and a subtlety of logic peculiar to yourself—­it brought, I say, your very acute understanding to see nothing clearly, and enveloped all the great truths of reason and religion in mists of doubt.

Bayle.—­I own it did; but your comparison is not just.  I did not see well before I used my philosophic eye-water.  I only supposed I saw well; but I was in an error, with all the rest of mankind.  The blindness was real; the perceptions were imaginary.  I cured myself first of those false imaginations, and then I laudably endeavoured to cure other men.

Locke.—­A great cure, indeed! and don’t you think that, in return for the service you did them, they ought to erect you a statue?

Bayle.—­Yes; it is good for human nature to know its own weakness.  When we arrogantly presume on a strength we have not, we are always in great danger of hurting ourselves—­or, at least, of deserving ridicule and contempt by vain and idle efforts.

Locke.—­I agree with you that human nature should know its own weakness; but it should also feel its strength, and try to improve it.  This was my employment as a philosopher.  I endeavoured to discover the real powers of the mind; to see what it could do, and what it could not; to restrain it from efforts beyond its ability, but to teach it how to advance as far as the faculties given to it by Nature, with the utmost exertion and most proper culture of them, would allow it to go.  In the vast ocean of philosophy I had the line and the plummet always in my hands.  Many of its depths I found myself unable to fathom; but by caution in sounding, and the careful observations I made in the course of my voyage, I found out some truths of so much use to mankind that they acknowledge me to have been their benefactor.

Bayle.—­Their ignorance makes them think so.  Some other philosopher will come hereafter, and show those truths to be falsehoods.  He will pretend to discover other truths of equal importance.  A later sage will arise, perhaps among men now barbarous and unlearned, whose sagacious discoveries will discredit the opinions of his admired predecessor.  In philosophy, as in Nature, all changes its form, and one thing exists by the destruction of another.