130 UNIVERSITY OF COLORADO STUDIES 



with it. For, even as children go about with a tottering and weakly- 

 body, so slender sagacity of mind follows along with it; thfen when 

 their Ufe has reached the maturity of confirmed strength, the judgment 

 too is greater and the power of mind more developed. Afterwards 

 when the body has been shattered by the mastering might of time 

 and the frame has drooped with the forces dulled, then the intellect 

 halts, the tongue dotes, the mind gives way, all faculties fail and are 

 found wanting at the same time. It naturally follows then that the 

 whole nature of the soul is dissolved, Uke smoke, into the high air; 

 since we see it is begotten along with the body and grows up along 

 v^dth it, and, as I have shown, breaks down at the same time, worn out 

 with age."' 



Haeckel: "The ontogenetic argument puts before us the facts 

 of the development of the soul in the individual; we see how the child- 

 soul gradually unfolds its various powers; the youth presents them 

 in full bloom, the mature man shows their ripe fruit; in old age we 

 see the gradual decay of psychic powers, corresponding to the degen- 

 eration of the brain. "* Inasmuch as the full significance of this sen- 

 tence is rather more easily grasped in connection with Haeckel 's 

 chapter on consciousness, I append in a note the passage of which 

 this is really a summary.^ A driving-home of this ontogenetic argu- 

 ment by Haeckel in another place belongs as naturally to Lucretius^ 



■ De R. N., 445-458. ' WR., 204. 



3 WR., 1 8s- 1 86: "As everybody knows, the new-bom infant has no consciousness. Preyer has shown 

 that it is only developed after the child has begun to speak; for a long time it speaks of itself in the third person. 

 In the important moment when it first pronounces the word 'I,' when the feeling of self becomes clear, we 

 have the beginning of self-consciousness, and of the antithesis to the non-ego. The rapid and solid growth 

 and progress in knowledge which the child makes in its first ten years, under the care of parents and teachers, 

 and the slower progress of the second decade, until it reaches complete maturity of mind, are intimately con- 

 nected with a great advancement in the growth and development of consciousness and of its organ, the brain* 

 But even when the pupil has got his 'certificate of maturity,' his consciousness is still far from mature; i 

 is then that his world-consciousness first begins to develop, in his manifold relations with the outer world. 

 Then, in the third decade, *e have the full maturity of rational thought and consciousness, which in cases of 

 normal development yield their ripe fruits during the next three decades. The slow, gradual degeneration 

 of the higher mental powers, which characterizes seniUty, usually sets in at the commencement of the seventh 

 decade, sometimes earlier, sometimes later; memory, receptiveness, and interest in particular objects grad- 

 ually decay; though productivity, mature consciousness, and philosophic interest in general truths often remain 

 for many years longer. 



"The individual development of consciousness in earlier youth proves the universal validity of the bio- 

 genetic law; and, indeed, it is still recognizable in many ways during the later years. In any case, the onto- 

 genesis of consciousness makes it perfectly clear that it is not an 'immaterial entity ,' but a physiologica' 

 ^unction of the brain, and that it is, consequently, no exception to the general law of substance." 



