I have now said as much as need be said about the relation of Assent to Apprehension, and shall turn to the consideration of the relation existing between Assent and Inference.
As apprehension is a concomitant, so inference is ordinarily the antecedent of assent;—on this surely I need not enlarge;—but neither apprehension nor inference interferes with the unconditional character of the assent, viewed in itself. The circumstances of an act, however necessary to it, do not enter into the act; assent is in its nature absolute and unconditional, though it cannot be given except under certain conditions.
This is obvious; but what presents some difficulty is this, how it is that a conditional acceptance of a proposition,—such as is an act of inference,—is able to lead, as it does, to an unconditional acceptance of it,—such as is assent; how it is that a proposition which is not, and cannot be, demonstrated, which at the highest can only be proved to be truth-like, not true, such as [pg 158] “I shall die,” nevertheless claims and receives our unqualified adhesion. To the consideration of this paradox, as it may be called, I shall now proceed; that is, to the consideration, first, of the act of assent to a proposition, which act is unconditional; next, of the act of inference, which goes before the assent and is conditional; and, thirdly, of the solution of the apparent inconsistency which is involved in holding that an unconditional acceptance of a proposition can be the result of its conditional verification.
§ 1. Simple Assent.
The doctrine which I have been enunciating requires such careful explanation, that it is not wonderful that writers of great ability and name are to be found who have put it aside for a doctrine of their own; but no doctrine on the subject is without its difficulties, and certainly not theirs, though it carries with it a show of common sense. The authors to whom I refer wish to maintain that there are degrees of assent, and that, as the reasons for a proposition are strong or weak, so is the assent. It follows from this that absolute assent has no legitimate exercise, except as ratifying acts of intuition or demonstration. What is thus brought home to us is indeed to be accepted unconditionally; but, as to reasonings in concrete matters, they are never more than probabilities, and the probability in each conclusion which we draw is the measure of our assent to that conclusion. Thus assent becomes a sort of necessary shadow, following upon inference, which is the substance; and is never without some alloy of doubt, because inference in the concrete never reaches more than probability.
Such is what may be called the à priori method of regarding assent in its relation to inference. It condemns [pg 160] an unconditional assent in concrete matters on what may be called the nature of the case. Assent cannot rise higher than its source; inference in such matters is at best conditional, therefore assent is conditional also.
Abstract argument is always dangerous, and this instance is no exception to the rule; I prefer to go by facts. The theory to which I have referred cannot be carried out in practice. It may be rightly said to prove too much; for it debars us from unconditional assent in cases in which the common voice of mankind, the advocates of this theory included, would protest against the prohibition. There are many truths in concrete matter, which no one can demonstrate, yet every one unconditionally accepts; and though of course there are innumerable propositions to which it would be absurd to give an absolute assent, still the absurdity lies in the circumstances of each particular case, as it is taken by itself, not in their common violation of the pretentious axiom that probable reasoning can never lead to certitude.
Locke’s remarks on the subject are an illustration of what I have been saying. This celebrated writer, after the manner of his school, speaks freely of degrees of assent, and considers that the strength of assent given to each proposition varies with the strength of the inference on which the assent follows; yet he is obliged to make exceptions to his general principle,—exceptions, unintelligible on his abstract doctrine, but demanded by the logic of facts. The practice of mankind is too strong for the antecedent theorem, to which he is desirous to subject it.