THE treatise which follows has in the main grown up in
connection with the author's class-room instruction in
Psychology, although it is true that some of the chapters
are more 'metaphysical,' and others fuller of detail, than
is suitable for students who are going over the subject for
the first time. The consequence of this is that, in spite of
the exclusion of the important subjects of pleasure and
pain, and moral and æsthetic feelings and judgments, the
work has grown to a length which no one can regret more
than the writer himself. The man must indeed be sanguine
who, in this crowded age, can hope to have many readers
for fourteen hundred continuous pages from his pen. But
wer Vieles bringt wird Manchem etwas bringen; and, by judi-
ciously skipping according to their several needs, I am sure
that many sorts of readers, even those who are just begin-
ning the study of the subject, will find my book of use.
Since the beginners are most in need of guidance, I sug-
gest for their behoof that they omit altogether on a first
reading chapters 6, 7, 8, 10 (from page 330 to page 371),
12, 13, 15, 17, 20, 21, and 28. The better to awaken the
neophyte's interest, it is possible that the wise order would
be to pass directly from chapter 4 to chapters 23, 24, 25,
and 26, and thence to return to the first volume again.
Chapter 20, on Space-perception, is a terrible thing, which,
unless written with all that detail, could not be fairly
treated at all. An abridgment of it, called 'The Spatial
Quale,' which appeared in the Journal of Speculative
Philosophy, vol. XIII. p. 64, may be found by some per-
sons a useful substitute for the entire chapter.
I have kept close to the point of view of natural science
throughout the book. Every natural science assumes cer-