It is indeed true that the three great classes of facts—the _universal_, or absolute (mathematical and metaphysical)—the _general_, or physical, and the _individual_ (forensic and historical) are pursued and ascertained by three corresponding methods, or, as they might be called, three logics. But it is far from being true that the three species of reasoning hold an _exclusive_ authority or sole jurisdiction over the three classes of facts above mentioned. Throughout the physical sciences the mathematical logic is perpetually resorted to, while even within the range of the mathematical the physical is, once and again, brought in as an aid. But if we turn to the _historical_ and _forensic_ department of facts, the three methods are so blended in the establishment of them, that to separate them altogether is impracticable; and as to _moral_ evidence, if we use the phrase in any intelligible sense, it does but give its aid, at times, on this ground; and even then the conclusions to which it leads rest upon inductions which are physical, rather than moral. The conduct of a complicated historical or forensic argument concerning individual facts, resembles the manipulations of an adroit workman, who, having some nice operation in progress, lays down one tool and snatches up another, and then another, according to the momentary exigencies of his task. That sort of evidence may properly be called _moral_, which appeals to the moral sense, and in assenting to which, as we often do with an irresistible conviction, we are unable, with any precision, to convey to another mind the grounds of our firm belief. It is thus often that we estimate the veracity of a witness or judge of the reality or spuriousness of a written narrative. But then even this sort of evidence, when nicely analyzed, resolves itself into physical principles. What are these convictions which we find it impossible to clothe in words, but the results in our minds, of slow, involuntary inductions concerning moral qualities, and which, inasmuch as they are peculiarly exact, are not to be transfused into a medium so vague and faulty as is language, at the best? As to the mass of history, by far the larger portion of it rests, in no proper sense, upon _moral_ evidence. To a portion the mathematical doctrine of probabilities applies—for it may be as a million to one—that an alleged fact, under all the circumstances, is true. But the proof of the larger portion resolves itself into our knowledge of the laws of the material world, and of those of the world of mind. A portion also is conclusively established by a minute scrutiny of its agreement with that intricate combination of small events which makes up the course of human affairs.