As regards their name, it being so much in point, excuses the old remark that the elements of our knowledge stand in a reversed order in respect to this knowledge to what they assume in our process of acquiring it. A first principle, therefore, means also a last one; it is the last in whatsoever endeavors to descend to the bottom or to penetrate to the source of our knowledge, but it becomes the first when we trace it from this source through its derivative ideas. The investigating act should not be confounded with the prospecting one. The sensible horizon of subjective vision can, by no mediation, be exalted into the real horizon of truth, wherein the genuine first principles that bound human capability are exclusively to be found. It may be asked, apart from the inquiry what first principles there are, Is there a necessity that some first principles should be? So it seems from the data of the case. It is patent to common observation that the mind of man is recipient of ideas from the things that surround it. The contact of its apprehending faculty with the things it apprehends, must, it would seem, constitute first principles. After it has got them it might conceivably elicit from them derived principles, but the original ones cannot be thus derived, since there are none earlier from which to derive them. Again, it is to be inquired, Does the mind, in receiving its ideas, possess and exercise in reference to the things on which it operates, a copying faculty or a transforming faculty? Does it import them simply in their native character, in the way a mirror does the object it reflects, or does it manufacture, cook, and assimilate them, so as to change them into something partaking of its own? And, if it changes them, what is the extent of the change? Does it go so far only as the semi-idealism of Locke, or extend into the absolute idealism of the German school? Because these questions have been wont to puzzle either the learned, or the public, or both, it does not follow that they are difficult. I suppose them to admit of decided answers before a supposed competent audience. As I am unprovided with proof, although I suppose it is to be provable, that first principles of reason must needs be, I must speculate for a moment on the possibility of a proposition of the form of "two and two make four," being derived from one of the form of "I scent the rose," for this seems to be the alternative of there being no first principles of reason. Evidently I must confess to having no grounds for pronouncing such a derivation impossible, though I must grant it to be paradoxical. Our mal-cultivation of non-material science, and the imperfection of our metaphysics, is probably the only cause of the strange predicament.