(1899)[151] and in the supplementary volume _Die
Lebenswunder_ (1904)[152] I have endeavoured to show that this pure
monism is securely established, and that the admission of the
all-powerful rule of the same principle of evolution throughout the
universe compels us to formulate a single supreme law--the
all-embracing "Law of Substance," or the united laws of the constancy
of matter and the conservation of energy. We should never have reached
this supreme general conception if Charles Darwin--a "monistic
philosopher" in the true sense of the word--had not prepared the way
by his theory of descent by natural selection, and crowned the great
work of his life by the association of this theory with a naturalistic
anthropology.

FOOTNOTES:

[Footnote 127: _Generelle Morphologie der Organismen_, 2 vols.,
Berlin, 1866.]

[Footnote 128: Eng. transl.; _The History of Creation_, London, 1876.]

[Footnote 129: London, 1908.]

[Footnote 130: Munich, 1884.]

[Footnote 131: _Die Mutationstheorie_, Leipzig, 1903.]

[Footnote 132: _Der Kampf der Theile im Organismus_, Leipzig, 1881.]

[Footnote 133: Leipzig, 1904.]

[Footnote 134: Berlin, 1876.]

[Footnote 135: _Wonders of Life_, London and New York, 1904.]

[Footnote 136: Eng. transl.; _The Evolution of Man_, 2 vols., London,
1879 and 1905.]

[Footnote 137: _Origin of Species_ (6th edit.), p. 396.]

[Footnote 138: Eng. transl.; _Facts and Arguments for Darwin_, London,
1869.]

[Footnote 139: 3 vols., Berlin, 1894-96.]

[Footnote 140: _Descent of Man_ (Popular Edit.), p. 927.]

[Footnote 141: _Gesammelte Abhandlungen zur wissenschaftlichen
Medizin_, Berlin, 1856.]

[Footnote 142: Eng. transl.; _Last Words on Evolution_, London, 1906.]

[Footnote 143: _Descent of Man_, (Popular Edit.), p. 255.]

[Footnote 144: _Descent of Man_, p. 930.]

[Footnote 145: Eng. transl.; _The History of Creation_, London, 1876.]

[Footnote 146: Berlin, 1894-96.]

[Footnote 147: Leipzig, 1874, 5th edit. 1905. Eng. transl.; _The
Evolution of Man_, London, 1905.]

[Footnote 148: London, 1898.]

[Footnote 149: _Festschrift zur 350-jaehrigen Jubelfeier der Thueringer
Universitaet Jena_. Jena. 1908.]

[Footnote 150: London, 1885; 1888.]

[Footnote 151: _The Riddle of the Universe_, London and New York,
1900.]

[Footnote 152: _The Wonders of Life_, London and New York, 1904.]

VI

MENTAL FACTORS IN EVOLUTION

BY C. LLOYD MORGAN, LLD., F.R.S

In developing his conce