It is, therefore, quite natural that we should find this belief in the immortality of the animal soul among many ancient and modern peoples; we even meet it sometimes to-day in many thoughtful men who postulate an "immortal life" for themselves, and have, at the same time, a thorough empirical knowledge of the psychic life of the animals. I once knew an old head-forester, who, being left a widower and without children at an early age, had lived alone for more than thirty years in a noble forest of East Prussia. His only companions were one or two servants, with whom he exchanged merely a few necessary words, and a great pack of different kinds of dogs, with which he lived in perfect psychic communion. Through many years of training this keen observer and friend of nature had penetrated deep into the individual souls of his dogs, and he was as convinced of their personal immortality as he was of his own. Some of his most intelligent dogs were, in his impartial and objective estimation, at a higher stage of psychic development than his old, stupid maid and the rough, wrinkled manservant. Any unprejudiced observer, who will study the conscious and intelligent psychic activity of a fine dog for a year, and follow attentively the physiological processes of its thought, judgment, and reason, will have to admit that it has just as valid a claim to immortality as man himself. The proofs of the immortality of the soul, which have been adduced for the last two thousand years, and are, indeed, still credited with some validity, have their origin, for the most part, not in an effort to discover the truth, but in an alleged "necessity of emotion"--that is, in imagination and poetic conceit. As Kant puts it, the immortality of the soul is not an object of pure reason, but a "postulate of practical reason." But we must set "practical reason" entirely aside, together with all the "exigencies of emotion, or of moral education, etc.," when we enter upon an honest and impartial pursuit of truth; for we shall only attain it by the work of pure reason, starting from empirical data and capable of logical analysis. We have to say the same of athanatism as of theism; both are creations of poetic mysticism and of transcendental "faith," not of rational science.