THE HISTORICAL SOCIOLOGISTS I7I 
gether to “ try out ” all possible conditions of life that the result 
may be the largest possible experience of individual, self-conscious 
life. This inborn interest is the prime factor in attention, associ- 
ation, purpose and will. ‘‘ One can apperceive nothing and think 
of nothing which does not conform to the interest inhering in 
it’? # 
The factors to be found in the lowest forms of organic life which 
make possible all further differentiation and development are as 
follows: — 
1. The Urkraft endowed with the capacity of struggling to 
ever increasing development under conditions imposed by the 
environment. 
2. Interest inborn in every creature. 
3. The power of assimilation or the physiological impulse, also 
rooted in the interest but possessing different influence because it 
works no longer merely through the Urkraft within the creature 
but draws to it particles from the outside world. 
4. The influence of the phenomenal world. The individual 
impelled by interest and struggling to come to completion, 
creates out of the conditions of life at hand the greatest possible 
advantage for the development of the species through variation 
and adaptation. 
5. Individuation, or the process by which the creature working 
through the inborn interest builds up a unitary consciousness. 
6. Reproduction as the result of the continuous working of the 
Urkraft in and through the individual. 
7. Heredity, whereby the creature is able to bring forth only a 
like offspring on the basis of his inner capacity.” 
Selection and struggle for existence are recognized as two 
further factors to be taken into consideration in the explanation 
of biological evolution.’ 
As a result of the struggle for development on the part of the 
Urkraft every “‘ preformed ” germ develops just in proportion as 
the conditions of life make possible, even to the expression of 
purposeful acts of civilized man.5 
1 Erkenntnis, p.34.  % Ibid., pp. 4of.  § Ibid., pp. 302 f.; Soziologie, p. 23. 
2 Tbid., pp. 38, 39. 4 Ibid., p. 46. 
