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  HUMAN LIFE

  BY
  S. S. KNIGHT

  [Illustration]

  NEW YORK
  R. F. FENNO & COMPANY
  18 EAST 17TH STREET




  COPYRIGHT, 1910,
  BY S. S. KNIGHT




CONTENTS


  CHAPTER                                               PAGE
     I. THE HABITAT OF MAN                                 9
    II. THE LENGTH OF TIME DURING WHICH MAN HAS EXISTED   29
   III. THE PHYSICAL LIMITATIONS OF EXISTENCE             56
    IV. THE PURPOSE OF LIFE                               76
     V. KNOWLEDGE AND EDUCATION                           99
    VI. RELIGION AND ETHICS                              120
   VII. LOVE                                             156
  VIII. PROBLEMS OF THE FUTURE                           180




DEDICATION


This volume is dedicated to my Mother and my Wife--the two women whose
influence has most largely shaped my life, and whose companionship
has afforded me so much happiness. It was written with the hope that
it might be of value to my two children, and may they find as much
happiness in life as has the author.




HUMAN LIFE




CHAPTER I

THE HABITAT OF MAN


In reviewing the facts concerning humanity, which are well
authenticated at the present date, with the object of getting a
composite view of the greatest of all "world riddles"--"Life"--possibly
nothing tends so largely to expand our mental horizon as a study of
the earth itself or man's place of abode. The ideas of the educated
and cultured mind, at the beginning of the twentieth century, upon
cosmogony, are necessarily of such a character that man's heretofore
undisputed boast of being the objective and acme of creation or
evolution is forced into that great mass of theories which science has
proven to be absolutely untenable. Since the relative importance of the
factors of heredity and adaptation has become known, the environment,
or conditions surrounding man's existence in times past, is of
exceptional importance, as, from an understanding of these prehistoric
limitations, we are better able to judge what must have been the
achievement of the individual and the race than we could be when in
ignorance of these facts.

The length of prehistoric time (so far as our earth is concerned) has
been the subject of much intelligent labor and thought, as well as
the occasion for much dissenting of opinion and more or less designed
misstatement. Until very recently, it has been difficult to reconcile
the theories, as promulgated by the authorities in the various
departments of science; but, notwithstanding this, some light may be
obtained by the summarization of the most plausible hypotheses now
advocated. We cannot take the space to go into detail concerning these,
but will merely touch upon the most salient points.

The constancy of the supply of heat furnished by the sun and the
division of the year into definite seasons was one of the first
phenomena which attracted the attention of man at the dawn of history,
and in the many accounts of the creation which we find in literature
we see the feeble attempts of man to account for what he observed.
Although the knowledge which we have at the present time is not
complete enough to warrant any feeling of pride, yet we do know enough
to say, with certainty, some things concerning the solar system. We
know that our sun cannot forever radiate away its heat into space
without sometime becoming as cold or colder than we are, unless the
energy which it is losing in the form of heat be restored to it by some
means not at this time known. Sir William Thomson (Lord Kelvin) has
calculated that at the present rate of solar radiation, which amounts
to about twenty-eight calories per minute, per square centimeter, at
the distance of the mean radius of the earth's orbit, it would have
taken somewhat more than fifteen million years for the heat generated
by the contraction of the sun's mass from the orbit of the outer
planet, Neptune, to its present size, to have been radiated away into
space. This means that gravity, as a source of heat development, at the
rate of solar radiation now known, would account for, perhaps, twenty
million years' expenditure of energy in reducing the sun's diameter to
but one-thirteen-thousandth part of what it once was. Not only does
the nebular hypothesis fall short of accounting for the facts, as will
subsequently be shown in this one