Fourthly, in no class of concrete reasonings, whether in experimental science, historical research, or theology, is there any ultimate test of truth and error in our inferences besides the trustworthiness of the Illative Sense that gives them its sanction; just as there is no sufficient test of poetical excellence, heroic action, or gentleman-like conduct, other than the particular mental sense, be it genius, taste, sense of propriety, or the moral sense, to which those subject-matters are severally committed. Our duty in each of these is to strengthen and perfect the special faculty which is its living rule, and in every case as it comes to do our best. And such also is our duty and our necessity, as regards the Illative Sense.
§ 3. The Range of the Illative Sense.
Great as are the services of language in enabling us to extend the compass of our inferences, to test their validity, and to communicate them to others, still the mind itself is more versatile and vigorous than any of its works, of which language is one, and it is only under its penetrating and subtle action that the margin disappears, which I have described as intervening between verbal argumentation and conclusions in the concrete. It determines what science cannot determine, the limit of converging probabilities and the reasons sufficient for a proof. It is the ratiocinative mind itself, and no trick of art, however simple in its form and sure in operation, by which we are able to determine that a moving body left to itself will never stop, and that no man can live without eating.
Nor, again, is it by any diagram that we are able to scrutinize, sort, and combine the many premisses which must be first run together before we answer duly a given question. It is to the living mind that we must look for the means of using correctly principles of whatever kind, facts or doctrines, experiences or testimonies, true or probable, and of discerning what conclusion from these is necessary, [pg 361] suitable, or expedient, when they are taken for granted; and this, either by means of a natural gift, or from mental formation and practice and a long familiarity with those various starting-points. Thus, when Laud said that he did not see his way to come to terms with the Holy See, “till Rome was other than she was,” no Catholic would admit the sentiment: but any Catholic may understand that this is just the judgment consistent with Laud’s actual condition of thought and cast of opinions, his ecclesiastical position, and the existing state of England.
Nor, lastly, is an action of the mind itself less necessary in relation to those first elements of thought which in all reasoning are assumptions, the principles, tastes, and opinions, very often of a personal character, which are half the battle in the inference with which the reasoning is to terminate. It is the mind itself that detects them in their obscure recesses, illustrates them, establishes them, eliminates them, resolves them into simpler ideas, as the case may be. The mind contemplates them without the use of words, by a process which cannot be analyzed. Thus it was that Bacon separated the physical system of the world from the theological; thus that Butler connected together the moral system with the religious. Logical formulas could never have sustained the reasonings involved in such investigations.
Thus the Illative Sense, that is, the reasoning faculty, as exercised by gifted, or by educated or otherwise well-prepared minds, has its function in the beginning, middle, and end of all discussion and inquiry, and in every step of the process. It is a rule to itself, and appeals to no judgment beyond its own; and attends upon the whole [pg 362] course of thought from antecedents to consequents, with a minute diligence and unwearied presence, which is impossible to a cumbrous apparatus of verbal reasoning, though, in communicating with others, words are the only instrument we possess, and a serviceable, though imperfect instrument.
One function indeed there is of Logic, to which I have referred in the preceding sentence, which the Illative Sense does not and cannot perform. It supplies no common measure between mind and mind, as being nothing else than a personal gift or acquisition. Few there are, as I said above, who are good reasoners on all subject-matters. Two men, who reason well each in his own province of thought, may, one or both of them, fail and pronounce opposite judgments on a question belonging to some third province. Moreover, all reasoning being from premisses, and those premisses arising (if it so happen) in their first elements from personal characteristics, in which men are in fact in essential and irremediable variance one with another, the ratiocinative talent can do no more than point out where the difference between them lies, how far it is immaterial, when it is worth while continuing an argument between them, and when not.
Now of the three main occasions of the exercise of the Illative Sense, which I have been insisting on, and which are the measure of its range, the start, the course, and the issue of an inquiry, I have already, in treating of Informal Inference, shown the place it holds in the final resolution of concrete questions. Here then it is left to me to illustrate its presence and action in relation to [pg 363] the elementary premisses, and, again, to the conduct of an argument. And first of the latter.