My object in the foregoing pages has been, not to form a theory which may account for those phenomena of the intellect of which they treat, viz. those which characterize inference and assent, but to ascertain what is the matter of fact as regards them, that is, when it is that assent is given to propositions which are inferred, and under what circumstances. I have never had the thought of an attempt which would be ambitious in me, and which has failed in the hands of others, if that attempt may not unfairly be called unsuccessful, which, though made by the acutest minds, has not succeeded in convincing opponents. Especially have I found myself unequal to antecedent reasonings in the instance of a matter of fact. There are those, who, arguing _à priori_, maintain, that, since experience leads by syllogism only to probabilities, certitude is ever a mistake. There are others, who, while they deny this conclusion, grant the _à priori_ principle assumed in the argument, and in consequence are obliged, in order to vindicate the certainty of our knowledge, to have recourse to the hypothesis of intuitions, intellectual forms, and the like, which belong to us by nature, and may be considered to elevate our experience into something more than it is in itself. Earnestly maintaining, as I would, with this latter school of philosophers, the certainty of knowledge, I think it enough to appeal to the common voice of mankind in proof of it. That is to be accounted a normal operation of our nature, which men in general do actually instance. That is a law of our minds, which is exemplified in action on a large scale, whether _à priori_ it ought to be a law or no. Our hoping is a proof that hope, as such, is not an extravagance; and our possession of certitude is a proof that it is not a weakness or an absurdity to be certain. How it comes about that we can be certain is not my business to determine; for me it is sufficient that certitude is felt. This is what the schoolmen, I believe, call treating a subject _in facto esse_, in contrast with _in fieri_. Had I attempted the latter, I should have been falling into metaphysics; but my aim is of a practical character, such as that of Butler in his _Analogy_, with this difference, that he treats of probability, doubt, expedience, and duty, whereas in these pages, without excluding, far from it, the question of duty, I would confine myself to the truth of things, and to the mind’s certitude of that truth.