The Descent of Man | Page 4

append a list. Some new illustrations have been introduced, and four of
the old drawings have been replaced by better ones, done from life by Mr. T.W. Wood. I
must especially call attention to some observations which I owe to the kindness of Prof.
Huxley (given as a supplement at the end of

Part I.), on the nature of the
differences between the brains of man and the higher apes. I have been particularly glad
to give these observations, because during the last few years several memoirs on the
subject have appeared on the Continent, and their importance has been, in some cases,
greatly exaggerated by popular writers.
I may take this opportunity of remarking that my critics frequently assume that I attribute
all changes of corporeal structure and mental power exclusively to the natural selection of
such variations as are often called spontaneous; whereas, even in the first edition of the
'Origin of Species,' I distinctly stated that great weight must be attributed to the inherited
effects of use and disuse, with respect both to the body and mind. I also attributed some
amount of modification to the direct and prolonged action of changed conditions of life.
Some allowance, too, must be made for occasional reversions of structure; nor must we
forget what I have called "correlated" growth, meaning, thereby, that various parts of the
organisation are in some unknown manner so connected, that when one part varies, so do
others; and if variations in the one are accumulated by selection, other parts will be
modified. Again, it has been said by several critics, that when I found that many details of
structure in man could not be explained through natural selection, I invented sexual
selection; I gave, however, a tolerably clear sketch of this principle in the first edition of
the 'Origin of Species,' and I there stated that it was applicable to man. This subject of
sexual selection has been treated at full length in the present work, simply because an
opportunity was here first afforded me. I have been struck with the likeness of many of
the half-favourable criticisms on sexual selection, with those which appeared at first on
natural selection; such as, that it would explain some few details, but certainly was not
applicable to the extent to which I have employed it. My conviction of the power of
sexual selection remains unshaken; but it is probable, or almost certain, that several of my
conclusions will hereafter be found erroneous; this can hardly fail to be the case in the
first treatment of a subject. When naturalists have become familiar with the idea of sexual
selection, it will, as I believe, be much more largely accepted; and it has already been
fully and favourably received by several capable judges.
DOWN, BECKENHAM, KENT, September, 1874.
First Edition February 24, 1871. Second Edition September, 1874.
CONTENTS.
INTRODUCTION.


PART I. THE DESCENT OR ORIGIN OF MAN.

CHAPTER I.
The Evidence of the Descent of Man from some Lower Form.
Nature of the evidence bearing on the origin of man--Homologous structures in man and
the lower animals--Miscellaneous points of correspondence--
Development--Rudimentary structures, muscles, sense-organs, hair, bones, reproductive
organs, etc.--The bearing of these three great classes of facts on the origin of man.

CHAPTER II.
On the Manner of Development of Man from some Lower Form.
Variability of body and mind in man--Inheritance--Causes of variability-- Laws of
variation the same in man as in the lower animals--Direct action of the conditions of
life--Effects of the increased use and disuse of parts-- Arrested
development--Reversion--Correlated variation--Rate of increase-- Checks to
increase--Natural selection--Man the most dominant animal in the world--Importance of
his corporeal structure--The causes which have led to his becoming erect--Consequent
changes of structure--Decrease in size of the canine teeth--Increased size and altered
shape of the skull--Nakedness --Absence of a tail--Defenceless condition of man.

CHAPTER III.
Comparison of the Mental Powers of Man and the Lower Animals.
The difference in mental power between the highest ape and the lowest savage,
immense--Certain instincts in common--The emotions--Curiosity--
Imitation--Attention--Memory--Imagination--Reason--Progressive improvement --Tools
and weapons used by animals--Abstraction, Self-consciousness-- Language--Sense of
beauty--Belief in God, spiritual agencies, superstitions.

CHAPTER IV.
Comparison of the Mental Powers of Man and the Lower Animals--continued.
The moral sense--Fundamental proposition--The qualities of social animals-- Origin of
sociability--Struggle between opposed instincts--Man a social animal--The more
enduring social instincts conquer other less persistent instincts--The social virtues alone

regarded by savages--The self-regarding virtues acquired at a later stage of
development--The importance of the judgment of the members of the same community
on conduct--Transmission of moral tendencies--Summary.

CHAPTER V.
On the Development of the Intellectual and Moral Faculties during Primeval and
Civilised times.
Advancement of the intellectual powers through natural selection-- Importance of
imitation--Social and moral faculties--Their development within the limits of the same