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 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 the elementary premisses, and, again, to the conduct of an argument. And first of the latter. 1.