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 particular of the length of time
during which our solar system has existed, but it does not account for
the variation in the obliquity of the poles of the planets, which are
the attendants upon the sun; nor does gravitative attraction alone
enable us to account for the tremendous velocities of some of the stars
through space, such as Arcturus,--so that it may be safely assumed that
we shall be forced to modify our ideas as to the value of the nebular
hypothesis as a working basis, before we can harmonize our deductions
from astronomical and geological grounds. Fortunately, the study of
the spiral nebulæ has done much to elucidate our conceptions of the
formation of the planetary systems, and from the discoveries made
concerning these highly attenuated bodies of matter, a new hypothesis
has been formed which will completely harmonize, perhaps, with these
above stated facts, which could not be made to accord with the nebular
theory as previously held.
One source of the continued acquisition of energy by our sun, whose
value is hard to estimate, is the shooting stars, or meteors, which
constantly fall into it. Astronomical records show that, from the earth
alone, no less than twenty million shooting stars are daily within
the limits of vision, and inasmuch as the solar system is moving with
a velocity of some twenty miles per second through space, it will be
seen that the number of meteors which would come within the influence
of the sun, being as it is about one and one-third million times the
volume of the earth, would be practically infinite. What then must be
said of the amount of energy acquired by the sun from these, although
each meteor may have a mass of but a few grams, and perhaps may be
only several hundred miles away from its successor? It is clearly
demonstrated that, if no such additions of energy were received by
our sun, in about ten million years its diameter would be reduced to
one-half of what it is now, and its mass, where now it exists as a gas,
would then become a solid, at least upon the surface, and the quantity
of heat received by the earth would become so small that life here, as
we know of it, would be an impossibility. But if it be granted that the
sun annually gathers, by its gravitative attraction, a combined mass
of matter equal to the one-hundredth part of our earth, at a distance
away from its center equal to the main radius of the earth's orbit, the
energy dissipated by its radiation of heat at its present rate would be
accounted for, while the sensible heat of the sun would not diminish,
and the supply would be kept up indefinitely. That such additions of
mass are made, there can be no doubt, but as to their quantity, we
cannot, with our present knowledge, even hazard a guess.
In speaking of the solar heat and man's dependence upon it in a
constant definite quantity, as one of the conditions of his existence,
perhaps it will give us some just appreciation of his place in nature
when we consider that the earth receives somewhat less than one
two-billionth part of the heat radiated away by the sun, and while
this expression makes the quantity which we receive seem rather small,
it is, nevertheless, large enough annually to melt a layer of ice one
hundred and seventy-five feet thick--all over the surface of the earth,
and is a little more than one six-thousandth part of the quantity of
heat which would be generated by the burning of a mass of coal as large
as the sun.
The researches of Halley and Adams have shown that from some cause,
probably the result of gravity acting in conjunction with the varying
eccentricity of the earth's orbit, the motion of the moon has been
slightly accelerated as time went on, while the diurnal motion of the
earth has been reduced by the action of the tides, and that the amount
of this loss, in time, is equal to about one second in the length of
our day, in 168,000 years. Now, this retardation in the earth's motion
has not taken place at a uniform rate if caused by the reaction of the
tides, as the nearer to the earth the moon was, the greater would be
the tides, and, consequently, the greater would be the reaction;
_i. e._, the retardation. But assuming that this retardation took
place, on the whole, at twice the rate now prevailing, we would still
have a period of six million years since the moon was thrown off by the
earth, when our days were but three hours long.
Turning from the theories of astronomy, which are obviously more or
less inaccurate, owing to their very nature and the character and
duration of the observations upon which they are based, we come to
the nearer and more certain deductions of geology. Here we have the
phenomena of denudation and deposition with which to deal, and inasmuch
as these are measurable at many places, and under many conditions
upon the earth to-day, it is safe to assume that computations made
from these measurements cannot be far from the truth. We know that
practically all of the great formations of the earth were depositions
of material from water which contained them, and that, in many
cases, heat caused these strata to be metamorphosed or crystallized
ages after they were deposited, and that in this crystallization
many of the fossils remaining imbedded in the deposited matter were
destroyed. Concerning this deposition we know that it is going on
to-day in the Atlantic and Pacific Oceans, where, in the deeper
portions the Globigerina ooze is filling in these depressions with a
deposit, resembling chalk, at the rate of perhaps an inch per century.
We know that the Gulf of Mexico and several other ocean areas are
being filled in with silt at the rate of as high as three inches
per century. This silt is brought down in the tributary rivers and
emptied into the gulfs. We also know that large areas in the Indian
Ocean are being covered with coral and the débris from the coral
reefs. We are absolutely certain that every geological period has had
its characteristic fauna and flora, and that, in both the animal and
vegetable kingdoms, some persistent types have connected it with both
the past and the future, so that the fossils have become the "open
sesame" to the geological records. We further know that the strata
composing the earth's surface are subject to elevation and subsidence,
such as is now going on in the delta of the Nile, on the coast of the
Netherlands, and in many other places, and that such movement is a
measurable quantity, given only the necessary time.
The total thickness of known strata measures but about one-three
hundred and twentieth part of the earth's diameter, or, in round
numbers, twenty-five miles. Thirty thousand feet of this is quite
readily identified as belonging to the old Archaic or Laurentian
period, and constitutes the oldest stratified deposit known. Even
in this, we find the remains of the Eozoon Canadense, which is now
universally acknowledged to be the petrifaction of a foraminiferous
living organism with a chambered shell. This means that, at this time,
the earth's atmosphere must have been very similar to what it is at the
present, and that the temperature of the sea was somewhere between the
boiling and the freezing points of water. What time had elapsed since
the earth was thrown off by the sun in an incandescent state can only
be faintly imagined. At the rate of deposition given for the deepest
of ocean deposits, this Archaic period would have taken perhaps
thirty-six million years; but inasmuch as the water may have been far
warmer then than now, and the rainfall more abundant, and the forces of
denudation in all respects more active, this figure may be excessive.
The next eighteen thousand feet of strata are easily identified as
Lower Silurian, by the Diatoms which occur imbedded in them, and these
formations include some of the largest deposits of limestone known. At
our rate of calculation, this deposit would require no less than nine
and one-half million years, and, in assuming this figure, no account
is made of the intervals of time during which no deposit took place,
although such periods of inactivity must necessarily have been. The
Upper Silurian strata consists of twenty thousand feet, the fossils of
which are the lower fishes, and for which we must assign a period of
time equal to no less than twenty-five million years, inasmuch as these
deposits are limestones and sandstones, or the remains of water-living
animals and plants.
Coming now to the Devonian and Carboniferous periods, the strata
of the former, which is filled with fossils of the dipnoi, and the
latter with those of the amphibia; we have deposits aggregating about
forty thousand feet, and inasmuch as long intervals of time must have
existed during the subsidence and elevation, and _vice versa_, of the
land, while the process of coal-forming was going on, it is certain
that our rate of deposition as heretofore used, is entirely too high.
Dawson and Huxley have estimated, after most careful investigation,
that the period of time consumed in laying down the coal measures,
could not be less than six million years, and upon this basis it is
safe to assume that between seventy-five and eighty million years were
consumed in laying down the Devonian and Carboniferous deposits. This
makes Paleozoic time occupy about one hundred and fifty million years,
which is probably under- rather than over-estimated. The flora of the
Carboniferous period was composed of tree ferns of the Sagillaria
and Lepidodendron species which have since become extinct; but the
Lingula, a shell in the Cambrian and Upper Silurian formations, and
the Terbratula, another shell, is found in the Devonian rocks. Both of
these are found living to-day, of the same identical genus and species.
In the Silurian rocks, we find the remains of an air-breathing
scorpion, very similar to that found to-day, which shows that the
atmosphere at that remote period was practically the same as we have at
the present time.
In the Mesozoic time, we find deposits aggregating some fifteen
thousand feet, and inasmuch as the Triassic sandstones were formations
of slow deposition, our heretofore established rate will not answer
the conditions. It has been estimated, after the most careful study
of the Triassic and Jurassic measures, that probably no less than
thirty million years were occupied by these periods, and that the
chalk deposits of the Cretaceous must have taken at the present
known rate, in like formations, somewhat over six million years of
ceaseless activity. This gives to Mesozoic time a period of thirty-six
million years, as a minimum, and, from what we know of the rate of
biological evolution, this figure is conservative. The first period
of the Mesozoic time was characterized by monotremes, the Jurassic by
marsupials, and the latter by the first of man's direct progenitors,
the placentals. The flora of this period consisted almost entirely of
gymnosperms, or naked seed plants, and, as far as we know, at the close
of this second great division of geological time, conditions on the
earth were, in all respects, very much as they are to-day.
Concerning the climatic conditions at the beginning of the Cenozoic
time, we have every reason to believe that from the commencement of
the Lower Silurian epoch, until then, there were no climatic zones
upon the earth. Not only have coral formations been found in what are
now Arctic waters, when we know that such reefs are formed only in
waters where a moderately warm temperature is constantly maintained,
but the cephalipods of the genus Ammonitoidea are found in what is now
the Antarctic zone, and in the torrid. While, at the present time, we
cannot see how the obliquity of the earth's poles to the plane of the
ecliptic could have been changed after the earth began its career as an
independent planet, yet the facts above stated show that the climatic
zones must have been unknown during the Tertiary period. Our common
cypress, which is now so plentiful in Florida and California, had
very close relatives living as far north as Spitzbergen, as lately as
Miocene time. Magnolias, which are now so abundant in all of the Gulf
States, are plentifully found in the Miocene strata of Greenland.
Returning to the length of the Tertiary period, it is well to note
that, covering Wyoming and Nebraska, there was an immense lake, at
least as large as Lake Superior is to-day, and into which several
quite large rivers emptied, whose head waters were in the surrounding
mountain ranges. This lake was at one time at least five thousand
feet deep, and was completely filled up by the fine mud and silt, as
the formation now shows, although at the known rate of filling in of
smaller modern lakes, into which rivers, which originate in glaciers,
empty, this would have taken the better part of fifty thousand years.
This figure is particularly conservative, as during the Eocene period,
there could have been neither glaciers nor melting snowfields to assist
in the denudation at the head waters of the tributary rivers. During
the Miocene period, many of the best geologists hold that America and
Europe were connected, and there are certain similarities in their
fauna and flora which make this very probable. Supposing that this
depression which constitutes the bed of the North Atlantic Ocean, took
place at the highest known rate of subsidence, as measured upon the
coast of Sweden to-day, it is almost impossible to state the amount
of time that necessarily elapsed from the beginning of the sinking of
this strip until it finally went below the surface of the water. That
such changes in level did take place in the Tertiary period, no one
can doubt, as chalk deposits in England, which must have been laid
down in the deep oceans, have now an elevation of thousands of feet.
The Nummulite limestone of this same period is found in both the Alps
and the Himalayas, at an elevation as great as ten thousand feet. The
consideration of the fact that the greatest known rate of elevation or
subsidence is, perhaps, scarcely more than two feet per century makes
the figure of five hundred thousand years, as a minimum for Pliocene
time, seem rather conservative.
Toward the close of the Tertiary era the finishing touches were placed
upon some of the greatest of the geological works. The folding of the
strata, which had been going on for a long period in Eastern New York,
was brought to an end by a violent rupture therein, and the out-rushing
igneous rock, which was subsequently cooled rapidly by the floods of
water flowing over it, gave us the beautiful palisades of the Hudson
River. In the west, this folding resulted in the Rocky Mountains and
the Coast Range, with their attendant high plateaux. In Europe, the
Alps and the Pyrenees Mountains both belong to this period, while the
grandest and highest of all mountain chains, the Himalayas, of Asia,
were the culminating effect of the gigantic foldings of the earth's
crust.
The deposits of the Tertiary period will aggregate somewhat more than
three thousand feet, and, inasmuch as this entire time was one of
continued change in level, or the fluctuation between the subsidence
of the earth's strata on the one hand and the elevation on the other
(particularly in the Pliocene period), it is very hard to form any
conjecture as to the actual amount of time required to do this work.
Certainly, from what we know of the rate at which like phenomena are
taking place at the present time in Northeastern North America, in
Northwestern Europe, and Western Asia, the figure, as sometimes given,
of ten million years seems very conservative.
In the brief review which we have just given, of what can be
conservatively considered the minimum limits of geological time, we
have taken into account generally only periods of activity, and in
but a few cases has any estimation been hazarded as to the proportion
which this was of the whole time consumed in bringing about the
changes which the fossils show so clearly to have taken place during
the various epochs. But one thing should be kept clearly in mind, and
that is, that no matter how long geological time may seem, it is but
an infinitely small fraction of the period which must have elapsed
since the world came into existence, as this globe had to cool down
to below the boiling point of water before any geological records
could be made. When thought of in this way, the Laurentian period
becomes as but yesterday, and even man's dwelling place, which seems
relatively so large, dwindles into nothingness, when compared with the
vastness of the interstellar spaces or the size of the larger stars.
Whoever conscientiously endeavors to form any idea of the teachings of
astronomy and geology, must necessarily feel any prejudice which he had
for man as the object and culmination of either the evolutionary or
creative power, shrink at a tremendous rate, while over his mentality
comes the sense of his diminutiveness, which awakens in him a brotherly
feeling for even the primitive single-celled Laurentian Eozoon
Canadensis, or the unnucleated monera of the present time. It must
have been this same sense-perception in the Hindoos which made them
worship and revere life wherever they found it, and which inspired them
with so active a sympathy toward all living things.