The following essays have been written and published at various times,
and my thanks are due to the previous publishers for the permission to
reprint them.
The essay on "Mysticism and Logic" appeared in the _Hibbert Journal_
for July, 1914. "The Place of Science in a Liberal Education" appeared
in two numbers of _The New Statesman_, May 24 and 31, 1913. "The Free
Man's Worship" and "The Study of Mathematics" were included in a
former collection (now out of print), _Philosophical Essays_, also
published by Messrs. Longmans, Green & Co. Both were written in 1902;
the first appeared originally in the _Independent Review_ for 1903,
the second in the _New Quarterly_, November, 1907. In theoretical
Ethics, the position advocated in "The Free Man's Worship" is not
quite identical with that which I hold now: I feel less convinced than
I did then of the objectivity of good and evil. But the general
attitude towards life which is suggested in that essay still seems to
me, in the main, the one which must be adopted in times of stress and
difficulty by those who have no dogmatic religious beliefs, if inward
defeat is to be avoided.
The essay on "Mathematics and the Metaphysicians" was written in 1901,
and appeared in an American magazine, _The International Monthly_,
under the title "Recent Work in the Philosophy of Mathematics." Some
points in this essay require modification in view of later work.
These are indicated in footnotes. Its tone is partly explained by the
fact that the editor begged me to make the article "as romantic as
possible."
All the above essays are entirely popular, but those that follow are
somewhat more technical. "On Scientific Method in Philosophy" was the
Herbert Spencer lecture at Oxford in 1914, and was published by the
Clarendon Press, which has kindly allowed me to include it in this
collection. "The Ultimate Constituents of Matter" was an address to
the Manchester Philosophical Society, early in 1915, and was published
in the _Monist_ in July of that year. The essay on "The Relation of
Sense-data to Physics" was written in January, 1914, and first
appeared in No. 4 of that year's volume of _Scientia_, an
International Review of Scientific Synthesis, edited by M. Eugenio
Rignano, published monthly by Messrs. Williams and Norgate, London,
Nicola Zanichelli, Bologna, and Félix Alcan, Paris. The essay "On the
Notion of Cause" was the presidential address to the Aristotelian
Society in November, 1912, and was published in their _Proceedings_
for 1912-13. "Knowledge by Acquaintance and Knowledge by Description"
was also a paper read before the Aristotelian Society, and published
in their _Proceedings_ for 1910-11.
LONDON,
_September, 1917_
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