cumstances common to all of them, on which their efficacy depends.
Besides, we find in the course of nature, that tho' the effects be many, the principles, from which they arise, are commonly but few and simple, and that 'tis the sign of an unskilful naturalist to have recourse to a different quality, in order to explain every different operation. How much more must this be true with regard to the human mind, which being so confin'd a subject may justly be thought incapable of containing such a monstrous heap of principles, as wou'd be necessary to excite the passions of pride and humility, were each distinct cause adapted to the passion by a distinct set of principles?
Here, therefore, moral philosophy is in the same condition as natural, with regard to astronomy before the time of Copernicus. The antients, tho' sensible of that maxim, that nature does nothing in vain, contriv'd such intricate systems of the heavens, as seem'd inconsistent with true philosophy, and gave place at last to something more simple and natural. To invent without scruple a new principle to every new phenomenon, instead of adapting it to the old; to overload our hypotheses with a variety of this kind; are certain proofs, that none of these principles is the just one, and that we only desire, by a number of falsehoods, to cover our ignorance of the truth.
SECTION IV.
Of the relations of impressions and ideas.
Thus we have establish'd two truths without any obstacle or difficulty, that ’tis from natural principles this variety of causes excite pride and humility, and that ’tis not by a different principle each different cause is adapted to its passion. We shall now proceed to enquire how we may reduce these principles to a lesser number, and find among the causes something common, on which their influence depends.
