Locke.—­Opinions taken up without a patient investigation, depending on terms not accurately defined, and principles begged without proof, like theories to explain the phenomena of Nature built on suppositions instead of experiments, must perpetually change and destroy one another.  But some opinions there are, even in matters not obvious to the common sense of mankind, which the mind has received on such rational grounds of assent that they are as immovable as the pillars of heaven, or (to speak philosophically) as the great laws of Nature, by which, under God, the universe is sustained.  Can you seriously think that because the hypothesis of your countryman Descartes, which was nothing but an ingenious, well-imagined romance, has been lately exploded, the system of Newton, which is built on experiments and geometry—­the two most certain methods of discovering truth—­will ever fail?  Or that, because the whims of fanatics and the divinity of the schoolmen cannot now be supported, the doctrines of that religion which I, the declared enemy of all enthusiasm and false reasoning, firmly believed and maintained, will ever be shaken?

Bayle.—­If you had asked Descartes, while he was in the height of his vogue, whether his system would be ever confuted by any other philosopher’s, as that of Aristotle had been by his, what answer do you suppose he would have returned?

Locke.—­Come, come, Monsieur Bayle, you yourself know the difference between the foundations on which the credit of those systems and that of Newton is placed.  Your scepticism is more affected than real.  You found it a shorter way to a great reputation (the only wish of your heart) to object than to defend, to pull down than to set up.  And your talents were admirable for that kind of work.  Then your huddling together in a critical dictionary a pleasant tale, or obscene jest, and a grave argument against the Christian religion, a witty confutation of some absurd author, and an artful sophism to impeach some respectable truth, was particularly commodious to all our young smarts and smatterers in freethinking.  But what mischief have you not done to human society!  You have endeavoured, and with some degree of success, to shake those foundations on which the whole moral world and the great fabric of social happiness entirely rest.  How could you, as a philosopher, in the sober hours of reflection, answer for this to your conscience, even supposing you had doubts of the truth of a system which gives to virtue its sweetest hopes, to impenitent vice its greatest fears, and to true penitence its best consolations; which restrains even the least approaches to guilt, and yet makes those allowances for the infirmities of our nature which the stoic pride denied to it, but which its real imperfection and the goodness of its infinitely benevolent Creator so evidently require?

Bayle.—­The mind is free, and it loves to exert its freedom.  Any restraint upon it is a violence done to its nature, and a tyranny against which it has a right to rebel.