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. First he says, in his chapter “On Probability,” “Most of the propositions we think, reason, discourse, nay, act upon, are such as we cannot have undoubted knowledge of their truth; yet some of them _border so near_ upon certainty, that we _make no doubt at all_ about them, but _assent_ to them _as firmly_, and act according to that assent as resolutely, _as if they were infallibly demonstrated_, and that our knowledge of them was perfect and certain.” Here he allows that inferences, which are only “near upon certainty,” are so near, that we legitimately accept them with “no doubt at all,” and “assent to them as firmly as if they were infallibly demonstrated.” That is, he affirms and sanctions the very paradox to which I am committed myself.