3. The third instance I will take is one of a literary character, the divination of the authorship of a certain anonymous publication, as suggested mainly by internal evidence, as I find it in a critique written some twenty years ago. In the extract which I make from it, we may observe the same steady march of a proof towards a conclusion, which is (as it were) out of sight;—a reckoning, or a reasonable judgment, that the conclusion really is proved, and a personal certitude upon that judgment, joined with a confession that a logical argument could not well be made out for it, and that the various details in which the proof consisted were in no small measure implicit and impalpable. “Rumour speaks uniformly and clearly enough in attributing it to the pen of a particular individual. Nor, although a cursory reader might well skim the book without finding in it anything to suggest, &c., ... will it appear improbable to the more attentive student of its internal evidence; and the improbability will decrease more and more, in proportion as the _reader is capable_ of judging and appreciating the _delicate, and at first invisible touches_, which limit, to _those who understand them_, the individuals who can have written it to a very small number indeed. The utmost scepticism as to its authorship (_which we do not feel ourselves_) cannot remove it farther from him than to that of some one among his most intimate friends; so that, leaving others to discuss antecedent probabilities,” &c. Here is a writer who professes to have no doubt at all about the authorship of a book,—which at the same time he cannot prove by mere argumentation set down in words. The reasons of his conviction are too delicate, too intricate; nay, they are in part invisible; invisible, except to those who from circumstances have an intellectual perception of what does not appear to the many. They are personal to the individual. This again is an instance, distinctly set before us, of the particular mode in which the mind progresses in concrete matter, viz. from merely probable antecedents to the sufficient proof of a fact or a truth, and, after the proof, to an act of certitude about it. I trust the foregoing remarks may not deserve the blame of a needless refinement. I have thought it incumbent on me to illustrate the intellectual process by which we pass from conditional inference to unconditional assent; and I have had only the alternative of lying under the imputation of a paradox or of a subtlety. § 3. Natural Inference.