And here I am brought to the bearing of these remarks upon my subject. For this law of progress is carried out by means of the acquisition of knowledge, of which inference and assent are the immediate instruments. Supposing, then, the advancement of our nature, both in ourselves individually and as regards the human family, is, to every one of us in his place, a sacred duty, it follows that that duty is intimately bound up with the right use of these two main instruments of fulfilling it. And as we do not gain the knowledge of the law of progress by any _à priori_ view of man, but by looking at it as the interpretation which is provided by himself on a large scale in the ordinary action of his intellectual nature, so too we must appeal to himself, as a fact, and not to any antecedent theory, in order to find what is the law of his mind as regards the two faculties in question. If then such an appeal does bear me out in deciding, as I have done, that the course of inference is ever more or less obscure, while assent is ever distinct and definite, and yet that what is in its nature thus absolute does, in fact follow upon what in outward manifestation is thus complex, indirect, and recondite, what is left to us but to take things as they are, and to resign ourselves to what we find? that is, instead of devising, what cannot be, some sufficient science of reasoning which may compel certitude in concrete conclusions, to confess that there is no ultimate test of truth besides the testimony born to truth by the mind itself, and that this phenomenon, perplexing as we may find it, is a normal and inevitable characteristic of the mental constitution of a being like man on a stage such as the world. His progress is a living growth, not a mechanism; and its instruments are mental acts, not the formulas and contrivances of language. We are accustomed in this day to lay great stress upon the harmony of the universe; and we have well learned the maxim so powerfully inculcated by our own English philosopher, that in our inquiries into its laws, we must sternly destroy all idols of the intellect, and subdue nature by co-operating with her. Knowledge is power, for it enables us to use eternal principles which we cannot alter. So also is it in that microcosm, the human mind. Let us follow Bacon more closely than to distort its faculties according to the demands of an ideal optimism, instead of looking out for modes of thought proper to our nature, and faithfully observing them in our intellectual exercises.