INTRODUCTION TO SOCIOLOGY 803
recall. Still the development of the myeline continues for a long time, perhaps the whole of life, with the practitioner, the savant, the philosopher. The intellectual centers become more and more specialized according to work, original aptitude, etc. Conversely, in cases of general paralysis the superficial fibers of association disappear first.
We see a vast field opened by this theory to psychology, and consequently to philosophy in general, and particularly to the philosophy of society. In every case, the result seems to be that the true distinction between the human species and the lower forms resides especially in the development of the associative centers; the latter are the characteristic marks of the human species. Perhaps some time evolution, verified in the relation of animals and of the child to the adult man, can be extended to different populations and can without too much boldness main- tain the hypothesis that ontogeny reproduces phylogeny. In such case one could proceed to a really positive classification of the varieties of the human species. That which precedes shows us, however, that the latter is fitted by its nervous organization to realize forms of adaptation and equilibration superior to all the other forms which we have considered. These more special, complex and, at the same time, co-ordinated forms are con- nected, nevertheless, with the whole of inorganic nature itself and prepare us for a clear comprehension of the diverse social equi- libriums.
SECTION VII. PSYCHICAL LIMITS.
From all our preceding observations it follows that all the natural phenomena, without exception, are subjected to condi- tions and laws which determine their structure. We have recog- nized these limits of variation, this equilibration, in the nervous system, and especially in its central and superior organ, the brain, when the most complex equilibration of all takes place that which results in the formation of centers of association which serve as the basis for the highest specialization represented by scientific knowledge, generalization, philosophical, and socio- logical abstraction. Let us now look at the psychical function itself and investigate whether in this class of phenomena, the
