454 Evolution and Modern Philosophy 
tendency to evolution in steady reciprocity with external conditions. 
The struggle for life is here only a secondary fact. Its apparent 
prominence is explained by the circumstance that the influence of 
external conditions is easily made out, while inner conditions can 
be verified only through their effects. For Ardigd the evolution of 
thought was the starting-point and the type: in the evolution of a 
scientific hypothesis we see a progress from the indefinite (indistinto) 
to the definite (distinto), and this is a characteristic of all evolution, 
as Ardigd has pointed out in a series of works. The opposition 
between indistinto and distinto corresponds to Spencer’s opposition 
between homogeneity and heterogeneity. The hypothesis of the 
origin of differences of species from more simple forms is a special 
example of the general law of evolution. 
In the views of Wundt and Fouillée we find the fundamental idea 
of idealism: psychical phenomena as expressions of the innermost 
nature of existence. They differ from the older Idealism in the great 
stress which they lay on evolution as a real, historical process which 
is going on through steady conflict with external conditions. The 
Romantic dread of reality is broken. It is beyond doubt that 
Darwin’s emphasis on the struggle for life as a necessary condition 
of evolution has been a very important factor in carrying philosophy 
back to reality from the heaven of pure ideas. The philosophy of 
Ardigd, on the other side, appears more as a continuation and 
deepening of positivism, though the Italian thinker arrived at his 
point of view independently of French-English positivism. The idea 
of continuous evolution is here maintained in opposition to Comte’s 
and Mill’s philosophy of discontinuity. From Wundt and Fouillée 
Ardigd differs in conceiving psychical evolution not as an immediate 
revelation of the innermost nature of existence, but only as a single, 
though the most accessible example, of evolution. 
III. To the French philosophers Boutroux and Bergson, evolution 
proper is continuous and qualitative, while outer experience and 
physical science give us fragments only, sporadic processes and 
mechanical combinations. To Bergson, in his recent work L' Evolu- 
tion Créatrice, evolution consists in an élan de vie which to our 
fragmentary observation and analytic reflexion appears as broken 
into a manifold of elements and processes. The concept of matter 
in its scientific form is the result of this breaking asunder, essential 
for all scientific reflexion. In these conceptions the strongest 
opposition between inner and outer conditions of evolution is ex- 
pressed : in the domain of internal conditions spontaneous develop- 
ment of qualitative forms—in the domain of external conditions 
discontinuity and mechanical combination. 
We see, then, that the theory of evolution has influenced philosophy 
