The highest that man can attain in these matters . . . is wonder; if the primary phenomenon causes this, let him be satisfied; more it cannot bring; and he should forbear to seek for anything further behind it; here is the limit. But the sight of a prime phenomenon is generally not enough for people. They think they must go still further, and are thus like children, who, after peeping into a mirror, turn round directly to see what is on the other side.