All good moral philosophy is ... but the handmaid to religion.

I well know what a spendidly great difference there is [between] a man and a bestia when I look at them from a point of view of morality. Man is the animal which the Creator has seen fit to honor with such a magnificent mind and has condescended to adopt as his favorite and for which he has prepared a nobler life; indeed, sent out for its salvation his only son; but all this belongs to another forum; it behooves me like a cobbler to stick to my last, in my own workshop, and as a naturalist to consider man and his body, for I know scarcely one feature by which man can be distinguished from apes, if it be not that all the apes have a gap between their fangs and their other teeth, which will be shown by the results of further investigation.

In science the new is an advance; but in morals, as contradicting our inner ideals and historic idols, it is ever a retrogression.

It seems perfectly clear that Economy, if it is to be a science at all, must be a mathematical science. There exists much prejudice against attempts to introduce the methods and language of mathematics into any branch of the moral sciences. Most persons appear to hold that the physical sciences form the proper sphere of mathematical method, and that the moral sciences demand some other method—I know not what.

Pope has elegantly said a perfect woman's but a softer man. And if we take in the consideration, that there can be but one rule of moral excellence for beings made of the same materials, organized after the same manner, and subjected to similar laws of Nature, we must either agree with Mr. Pope, or we must reverse the proposition, and say, that a perfect man is a woman formed after a coarser mold.

Science cannot resolve moral conflicts, but it can help to more accurately frame the debates about those conflicts.

Scientific truth is marvellous, but moral truth is divine; and whoever breathes its air and walks by its light has found the lost paradise.

The earth's becoming at a particular period the residence of human beings, was an era in the moral, not in the physical world?that our study and contemplation of the earth, and the laws which govern its animate productions, ought no more to be considered in the light of a disturbance or deviation from the system, than the discovery of the satellites of Jupiter should be regarded as a physical event in the history of those heavenly bodies, however influential they may have become from that time in advancing the progress of sound philosophy among men.

The fact that man knows right from wrong proves his intellectual superiority to other creatures; but the fact that he can do wrong proves his moral inferiority to any creature that cannot.

The progress of mankind is due exclusively to the progress of natural sciences, not to morals, religion or philosophy.

There is a moral or metaphysical part of nature as well as a physical. A man who denies this is deep in the mire of folly. 'Tis the crown and glory of organic science that it does through final cause, link material and moral; and yet does not allow us to mingle them in our first conception of laws, and our classification of such laws, whether we consider one side of nature or the other. You have ignored this link; and, if I do not mistake your meaning, you have done your best in one or two pregnant cases to break it. Were it possible (which, thank God, it is not) to break it, humanity, in my mind, would suffer a damage that might brutalize it, and sink the human race into a lower grade of degradation than any into which it has fallen since its written records tell us of its history.