is frequently dogmatical, even to intolerance; and while illustrating the feebleness of all human reasoning, he seems as if he felt an innate infallibility in his own. He afterwards regretted this peculiarity; and in a letter, written apparently at an advanced period of life, we find him deprecating not only the tone of the Inquiry, but many of its opinions. He says:-- "Allow me to tell you, that I never asserted so absurd a proposition as _that any thing might arise without a cause_. I only maintained that our certainty of the falsehood of that proposition proceeded neither from intuition nor demonstration, but from another source. _That Cæsar existed_, that there is such an island as Sicily,--for these propositions, I affirm, we have no demonstration nor intuitive proof,--would you infer that I deny their _truth_, or even their certainty? There are many different kinds of certainty; and some of them as satisfactory to the mind, though perhaps not so regular as the demonstrative kind. "Where a man of sense mistakes my meaning, I own I am angry; but it is only with myself, for having expressed my meaning so ill, as to have given occasion to the mistake. "That you may see I would no way scruple of owning my mistakes in argument, I shall acknowledge (what is infinitely more material) a very great mistake in conduct, viz. my publishing at all the 'Treatise of Human Nature,' a book which pretended to innovate in all the sublimest paths of philosophy, and which I composed before I was five-and-twenty; above all, the positive air which prevails in that book, and which may be imputed to the ardour of youth, so much displeases me, that I have not patience to review it. But what success the same doctrines, better illustrated and expressed, may meet with, _adhuc sub judice lis est_. The arguments have been laid before the world, and by some philosophical minds have been attended to. I am willing to be instructed by the public; though human life is so short, that I despair of ever seeing the decision. I wish I had always confined myself to the more easy parts of erudition; but you will excuse me from submitting to a proverbial decision, let it even be in Greek."[98:1]