His starting-point, in proving the doctrine of the immortality of the soul, is the fact of the existence of God, of which he has the highest possible certainty. The soul is the work of God, just as the body is; the body does not actually perish after dissolution, but is transformed into other elements; much less, then, can the soul, a simple essence, be decomposed, and perish. Further, God has acquainted the soul with the idea of immortality, has implanted it in the soul. Can He, the Benevolent and True One, practice deception? "If our soul were mortal, then reason would be a dream, which Jupiter has sent us that we may forget our misery; and we would be created like the beasts, only to seek food and die." Every thought inborn in man must for that reason be true and real. In demonstrating the doctrine of immortality, Mendelssohn had another noble purpose in view. He thought to counteract the malady of talented youths of the day, the Jerusalem-Werthers, who, without a goal for their endeavors, excluded from political and elevating public activity, lost in whimsical sentimentality and self-created pain, sank to thoughts of suicide, which they carried out, unless courage, too, was sicklied over. Mendelssohn, therefore, in his "Phædon" sought to inculcate the conviction, that man, with his immortal soul, is a possession of God, and has no manner of right to decide arbitrarily about himself and his life, or about the separation of his soul from his body--feeble argumentation, but sufficient for that weakly, effeminate generation.