Those very philosophers, who carried their skepticism the farthest, agreed upon the necessity of accommodating themselves in practice to the appearances of the senses, and of reserving doubt for the world of speculation. Philosophers may dispute on every thing as much as they please, but, the dispute over, they cease to be philosophers, and are again men, similar to other men, and, like them all, enjoy the fruits of certainty. This, Hume, who denied with Berkely the existence of bodies, confesses: "I dine," he says; "I play a game at backgammon; I converse, and am happy with my friends; and when, after three or four hours of amusement, I would return to these speculations, they appear so cold, so strained, and so ridiculous, that I cannot find it in my heart to enter into them any farther. Here, then, I find myself absolutely and necessarily determined to live, and talk, and act, like other people, in the common affairs of life."[2] [2] _Treatise of Human Nature_, vol. i., p. 467. 13. We must, in discussing certainty, guard against the feverish desire of shaking the foundations of human reason. We should, in this class of questions, seek a thorough knowledge of the principles of science, and the laws which govern the development of our mind. To labor to destroy them is to mistake the object of true philosophy: we have only to make them a matter of observation, just as we do those of the material world, without any intention of disturbing the admirable order prevailing in the universe. Skeptics, who, in order to render their philosophy more solid, begin by doubting every thing, resemble the man, who, desirous of ascertaining, and exactly determining the phenomena of life, should bare his bosom, and thrust the knife into his heart. Sobriety is as necessary to the health of the mind, as to that of the body: there is no wisdom without prudence, no philosophy without judgment. In the soul of man there is a divine light which directs him with admirable certainty. If we do not persist in extinguishing it, its splendor guides us, and when we reach the term of science it shows it to us, and makes us read in distinct characters the words,--_enough, you can go no farther_. These words are written by the Author of all beings; he it is that has given laws to the body as well as to the mind, and he contains in his infinite essence the ultimate reason of all things. 14. The certainty which is prior to all examination is not blind; on the contrary, it springs either from the clearness of the intellectual vision, or from an instinct conformable to reason: it is not opposed to reason, but is its basis. Our mind, in discursive reasoning, knows truth by the connection of propositions, or by the light which is reflected from one truth upon another. In primitive certainty the vision is by direct light, and does not need reflection.