psychology is treated
as a _physical_ science, on the same laws as the whole of
physiology, of which it is only a part; thirty years afterwards he
finds psychology to be a _spiritual_ science, with principles and
objects entirely different from those of physical science.

"I myself," says Haeckel, "naturally consider the 'youthful sin' of
the young physiologist Wundt to be a correct knowledge of nature,
and energetically defend it against the antagonistic view of the
old philosopher Wundt. This entire change of philosophical
principles, which we find in Wundt, as we found it in Kant,
Virchow, du Bois-Reymond, Carl Ernst Baer, and others, is very
interesting" (p. 36).

So it is: very interesting!

Professor Haeckel is so imbued with biological science that he loses
his sense of proportion; and his enthusiasm for the work of Darwin
leads him to attribute to it an exaggerated scope, and enables him to
eliminate the third of the Kantian trilogy:--

"Darwin's theory of the natural origin of species at once gave us
the solution of the mystic 'problem of creation,' the great
'question of all questions'--the problem of the true character and
origin of man himself" (p. 28) [_cf._ p. 19 above].

It is a great deal more than that patient observer and deep thinker
Charles Darwin ever claimed, nor have his wiser disciples claimed it
for him. It is familiar that he explained how variations once arisen
would be clinched, if favourable in the struggle, by the action of
heredity and survival; but the source or origin of the variations
themselves he did not explain.

Do they arise by guidance or by chance? Is natural selection akin to
the verified and practical processes of artificial selection? or is it
wholly alien to them and influenced by chance alone? The latter view
can hardly be considered a complete explanation, though it is verbally
the one adopted by Professor Haeckel, and it is of interest to see what
he means by chance:--

"Since impartial study of the evolution of the world teaches us
that there is no definite aim and no special purpose to be traced
in it, there seems to be no alternative but to leave everything to
'blind chance.'

"One group of philosophers affirms, in accordance with its
teleological conception, that the whole cosmos is an orderly
system, in which every phenomenon has its aim and purpose; there is
no such