It must necessarily, indeed, be allowed, that, in order to carry men's attention beyond the visible course of things, or lead them into any inference concerning invisible intelligent power, they must be actuated by some passion, which prompts their thought and reflection; some motive, which urges their first enquiry. But what passion shall we here have recourse to, for explaining an effect of such mighty consequence? Not speculative curiosity surely, or the pure love of truth. That motive is too refined for such gross apprehensions, and would lead men into enquiries concerning the frame of nature; a subject too large and comprehensive for their narrow capacities. No passions, therefore, can be supposed to work upon such barbarians, but the ordinary affections of human life; the anxious concern for happiness, the dread of future misery, the terror of death, the thirst of revenge, the appetite for food and other necessaries. Agitated by hopes and fears of this nature, especially the latter, men scrutinize, with a trembling curiosity, the course of future causes, and examine the various andcontrary