Its resisting our analysis is a good subjective ground for our ranking this and other similar propositions among our first principles. But they could only have the true claim by its being made clear that the inability results from the nature of the case, and not from our own incompetency. This test is borne by the former description of first principles; we are able to see that the instances I adduced, such as the statements, "I see the sun," "I see an inkstand," "I hear a bird," "I am conscious that I exist," evade our power of ordinary proving, because they do not admit of such proof. When we perceive that no one can answer this query, we are prompted to another. Why cannot we answer it? whence our inability? what prevents us? But here also we find ourselves completely in the dark, which is somewhat strange, considering that in every human pursuit, whether of science or any other, when we wish to do a thing and cannot do it, we are generally able to specify some particular, either of self-defect or outward impediment that is supposed to be in fault. But I imagine, if the reader were to experiment on the specimen I have given, he would not only find himself to fail in solving the problem, Why is it that a thing cannot at once be and not be? but would not have a word to advance in the way of accounting for his failure. These remarks apply to all other propositions of the sort. Euclid's axioms, which undoubtedly aim to be as elementary as possible, and therefore may be said to aim to be first principles, are confessedly, under this aspect, unsatisfactory to the learned. "Things that are equal to the same are equal to each other." Every one is inclined to ask, Why? "A straight line is the shortest distance between two points." Again, Why? The sum of the above strictures on this kind of so-called first principles, is--1. That they have not made good their title, and therefore are not to be accredited with it. 2. That there is a decided presumption against that title from the doubt and dissatisfaction with which it is met, where want of candor and intelligence cannot be imputed, especially when it is considered that the other, the sensuous experimental kind of first principles, have so frank an acceptance. 3. It seems to be absolutely provable, and I suppose I have above incidentally proved it, that they are not first principles. 4. The task is set to metaphysics of supplying the most satisfactory proof of all by bringing to light such propositions as would be perceived to underlie these so-called first principles, and to be the real first principles to which the others would give precedence.