Now if man possesses this faculty, however acquired, and by whatever name called, then if nature's laws are universal, he is both bound to use it, will suffer from not using it, and will have a proper field provided for its use. Nature gives no faculty without imposing an obligation of exercising it: an obligation, however, which rests in its full force upon the species, and upon the individual only as belonging to the species. Some powers every individual must use or he would die; there are other powers which, if he does not use, nature will be content with a lighter penalty. Far be it from me to affirm that every one here uses his reasoning powers. I hope he does; but if he does not use them, I am quite sure that nature will exact of him the penalty of stupidity. But the species must use them; if not, upon degradation would soon follow extinction. Nature, for instance, would not let man exist as a mere animal. If he did not use his reason, the instincts of other animals are so superior to his, that while they found food he would be unable to do so. Even if necessity quickened his instincts, he would yet have ceased to be a man, and would be retrograding back to the ascidian. To continue to be a man he must make some low use at all events of his mental powers. Now, can you establish any such difference between man's intellectual and moral powers, as will justify you, while acknowledging that you must use the one, in neglecting the other? Can you give any reason why you need not use the faculty which undoubtedly you possess of distinguishing between right and wrong, and the faculty, let us say, of "using the imagination in matters of science." I am sure you cannot. By not using your mental powers you will be in an inferior mental position; by not using your moral powers you will hold an inferior moral position.