e men; but there is
no stroke of their pen but which should be read with great
attention--besides which there is a very valuable literature about their
work.

(1) The purely mathematical foundation:

RUSSELL, BERTRAND.

"The Principles of Mathematics." Cambridge University, 1903.

(I am not giving any selections from the contents of this book because
this book should, without doubt, be read by every one interested in
mathematical philosophy.)

"The Problems of Philosophy." H. Holt & Co., N. Y., 1912.

"Our Knowledge of the External World, as a Field for Scientific Method in
Philosophy." Chicago, 1914.

"Introduction to Mathematical Philosophy." Macmillan, N. Y.

Selection from contents: Definition of number. The Definition of order.
Kinds of relations. Infinite cardinal numbers. Infinite series and
ordinals. Limits and continuity. The axiom of infinity and logical types.
Classes. Mathematics and logic.

"Mysticism and Logic." Longmans Green & Co. 1919. N. Y.

Selection from contents: Mathematics and the metaphysicians. On scientific
method in philosophy. The ultimate constituents of matter. On the notion
of cause.

WHITEHEAD, ALFRED N.

"An Introduction to Mathematics." Henry Holt & Co. 1911. N. Y.

"The Organization of Thought Educational and Scientific." London, 1917.

Selections from contents: The principles of mathematics in relation to
elementary teaching. The organization of thought. The anatomy of some
scientific ideas. Space, time, and relativity.

"An Enquiry Concerning the Principles of Natural Knowledge." Cambridge,
1919.

Selection from contents: The traditions of science. The data of science.
The method of extensive abstraction. The theory of objects.

"The Concept of Nature." Cambridge, 1920.

Selection from contents: Nature and thought. Time. The method of extensive
abstraction. Space and motion. Objects. The ultimate physical concepts.

"Principia Mathematica." By A. N. Whitehead and Bertrand Russell.
Cambridge, 1910-1913.

This monumental work stands alone. "As a work of constructive criticism it
has never been surpassed. To every one and especially to philosophers and
men of natural science, it is an amazing revelation of how the familiar
terms with which they deal plunge their roots far into the darkness
beneath the surface of common sense. It is a noble monument to the
critical spirit of science and to the idealism of our time."

"Human Worth of Rigorous Thinkin