The moral equality is still less open to reasonable exception. By moral equality I understand, the propriety of applying one unalterable rule of justice to every case that may arise. This cannot be questioned, but upon arguments that would subvert the very nature of virtue. "Equality," it has been affirmed, "will always be an unintelligible fiction, so long as the capacities of men shall be unequal, and their pretended claims have neither guarantee nor sanction by which they can be enforced." But surely justice is sufficiently intelligible in its own nature, abstractedly from the consideration whether it be or be not reduced into practice. Justice has relation to beings endowed with perception, and capable of pleasure and pain. Now it immediately results from the nature of such beings, independently of any arbitrary constitution, that pleasure is agreeable and pain odious, pleasure to be desired and pain to be disapproved. It is therefore just and reasonable that such beings should contribute, so far as it lies in their power, to the pleasure and benefit of each other. Among pleasures, some are more exquisite, more unalloyed and less precarious than others.
It is just that these should be preferred.
From these simple principles we may deduce the moral equality of mankind.
We are partakers of a common nature, and the same causes that contribute to the benefit of one will contribute to the benefit of another. Our senses and faculties are of the same denomination. Our pleasures and pains will therefore be alike. We are all of us endowed with reason, able to compare, to judge and to infer. The improvement therefore which is to be desired for one is to be desired for another. We shall be provident for ourselves, and useful to each other in proportion as we rise above the sphere of prejudice.