Mr. Hume has justly observed, that "all the sciences have a relation to human nature; and, however wide any of them may seem to run from it, they still return back by one passage or another. This is the centre and capitol of the sciences, which being once masters of, we may easily extend our conquests everywhere." The faculties of our minds are the tools and engines we must use in every disquisition; and the better we understand their nature and force, the more successfully we shall be able to apply them.