As these characteristics, like every thing which the mind can recognize as true, all have their origin in its natural desires, they may also be termed Principles; and as such we shall consider them. In order, however, to satisfy ourselves that they are truly such, and not arbitrary assumptions, or the traditional dogmas of Practice, it may be well to inquire whence is their authority; for, though the ultimate cause of pleasure and pain may ever remain to us a mystery, yet it is not so with their intermediate causes, or the steps that lead to them.