POSIDONIUS.—How can you imagine that two bodies, neither of which can think apart, should be able to produce thought, when joined together? LUCRETIUS.—In the same manner as a tree and earth, when taken separately, do not produce fruit, but do so when the tree is planted in the earth. POSIDONIUS.—The comparison is only specious. This tree has in it the seeds of fruit: we plainly perceive them in the buds, and the moisture of the earth unfolds the substance of these fruits. Fire, therefore, must possess in itself the seeds of thought, and the organs of the body serve only to develop these seeds. LUCRETIUS.—And do you find anything impossible in this? POSIDONIUS.—I find that this fire, this highly refined matter, is as devoid of the faculty of thinking as a stone. The production of a being must have something similar to that which produced it; but thought, will, and perception have nothing similar to fiery matter. LUCRETIUS.—Two bodies, struck against each other, produce motion, and yet this motion has nothing similar to the two bodies; it has none of their three dimensions, nor has it any figure. A being, therefore, may have nothing similar to that which produced it, and, in consequence, thought may spring from an assemblage of two bodies which have no thought. POSIDONIUS.—This comparison likewise is more specious than just. I see nothing but matter in two bodies in motion: I only see bodies passing from one place to another. But when we reason together I see no matter in your ideas, or in my own. I shall only observe that I can no more conceive how one body has the power of moving another, than I can comprehend the manner of my having ideas. To me both are equally inexplicable, and both equally prove the existence and the power of a Supreme Being, the author of thought and motion. LUCRETIUS.—If our soul is not a subtile fire, an ethereal quintessence, what is it? POSIDONIUS.—Neither you nor I know aught of the matter. I will tell you plainly what it is not; but I cannot tell you what it actually is. I see that it is a power lodged in my body; that I did not give myself this power; and, in consequence, that it must have come from a Being superior to myself. LUCRETIUS.—You did not give yourself life; you received it from your father; from whom, likewise, together with life, you received the faculty of thinking, as he had received both from his father, and so on backwards to infinity. You no more know the true principle of life than you do that of thought. This succession of living and thinking beings has always existed.