It will be necessary for us to consider before proceeding, what is meant by the term soul; and this becomes a somewhat difficult task, as the term has been variously applied to signify the principle of life in an organic body, or the first and most undeveloped stages of individualized spiritual being, or finally, all stages of spiritual individuality, incorporeal as well as corporeal.[76] The popular belief is, that the soul is not material but substantial, a divine gift to the highest alone of God's creatures; but scientific men, such as Carl Vogt, Moleschott, Büchner, Schmidt, Haeckel, consider the phenomena of the soul to be functions of the brain and nerves. Schmidt says: "The soul of the new-born infant is, in its manifestations, in no way different from that of the young animal. These are the functions of the infantine nervous system, with this they grow and are developed together with speech." The idea of the immortality of the soul was not aboriginal with mankind, as Sir J. Lubbock has shown that the barbarous races possess no clear belief of this kind, and Rajah Brook, at a missionary meeting in Liverpool, told his hearers there that the Dyaks, a people with whom he was connected, had no knowledge of God, of a soul, or of any future state. Darwin remarks, that "man may be excused for feeling some pride at having risen, though not through his own exertions, to the very summit of the organic scale; and the fact of his having thus risen, instead of having been aboriginally placed there, may give hope for a still higher destiny in the distant future." The belief in a future life amongst the civilized race of mankind is almost universally prevalent. The proofs of immortality are various. The desire that man has to live forever and his horror of annihilation is one; the good suffer in this world and the wicked triumph--this would indicate the necessity of future retribution. The infinite perfectibility of the human mind never reaches its full capacity in this life; the faculty of insight which sees in an individual all its past history at a glance is the immortal attribute and is continually on the increase; and it is possible that Aristotle was right so far as he stated that the lower faculties of the soul, such as sensation, imagination, feeling, memory, etc., are perishable. No matter if this be so or not, it is certain that in the next life, where all is perfection, only the fittest attributes will exist, the others would have perished. The doctrine of the immortality of the soul has been defended by Marhemeke, Blasche, Weisse, Hinnichs, Fecham, J. H. Fichte, and others.