The sun., 1900-12-23

and launched the theory oi evolution IN t,e word
OF that theory Mr. Wallace has ever since con
unued ~ be the chief eNtoSto AMI popglarlef smong
Enyish.sp.aflng peoples lie has been honorrC
with the degrees ~ Ill. ~ hy Dublin University AM
ofD. c l.. by Oyiori with the Royal Mtia. and tn
nrst Darwin Medal Of tho Royal Nod,ty with th,
gold medals Of the Royal Geographical Society, o
she Paris S'cet de Gtogfaphl. and ~ the lirn~at
Society III, Malay AIchIpc'ago,' "Geogfaphl
cal Distribution OF Animals" Tropical Mature
'band LIFE and "DaTvln'sm- have become classics
In science. No man can better ant more suihon
tauvely tell the wonderful ta.e o evolution than he
Among the great and fertile scientific
conceptions which have either originated
or become firmly established during the
nineteenth century, the theory OF evolution.
II not the greatest Of them all will certainly
take its place in the front rank. A par
tial explanation for no complete eXplana-
ton Is possible % finite inteligencel Of the
phenomena OF nature 1t illuminateS every
department OF science from tho study OF
the most remote cosmiC phenomena ac-
cessbIe to US to that of the ninutest organ
isms revealed by the most powerful micro
scopes; while upon the great problem Of the
mode Of origin of the various forms OF life
long considered insoluble-it throws so
clear a light that 10 many biologists It
seems 10 afford "a complete a solution.
In principle. as we can expect to reach.
THE NATURE AND LIMITS OF EVOLUTION.
So many Of the objections which are
still made to the theory Of evolution. and
especially to that branch Of 1t which deals
with living organisms. rest upon mis-
conception of what il processes to explain.
and even of what any theory can possibly
explain that a few words on its nature
and limits seem 10 be necessary.
Evolution. as general principle. I'M
plies that all things in the universe as NO
see them have arisen from other things
which preceded them by a process of modi-
f1cation. under the action of those all-per-
vadng but mysterious agencies known to
us as natura! forces" or more generally
the :" laws Of nature" More particularly
the term evolution implies that the process
Is an unrollinS or unfolding" derived
probably from the way in which leaves and
flowers are usually rolled up or crumpled
up In the bud and grow into their perfect
form by unrollinG or unfolding Insects
In the pupa and vertebrates in the embryo
exhibit somewhat similar condition OF
folding and the word IA therefore very
applicable to an extensive range Of phe-
nomena but Il must not be taken as uni
versaly applicable. since in the material
world there are other modes Of orderly
change under natural laws to which the
terms development or evolution are equally
applicable. The continuity" OF physical
phenomena rs illustrated by the late Sir
William Grove in 1866 has the same general
meaning. but evolution Implies more than
mere continuity or succession something
like growth or definite change from form
to form under the action Of Interchangeable
laws.
The point especially 10 he noted here Il.
that evolution. even II 1t Il essentially a
true and complete theory of the universe
can only explain the existing conditions
Of nature by showing that II has been de.
rived from some precxistlng condition
through the action of known forces and
laws. 1t may also show the high proba.
bility of similar derivation from a still
earlier condition: but the farther back we
60 the more uncertain must be our con-
clusions. while We can never make any
real approach 10 the absolute beginnings
Of things Herbert Spencer, and many
other thinkers before him. have shown
that II We try to realize the absolute nature
OF the simplest phenomena. We ara IN
evitably landed either in a contradiction
or In some unth!nkablc proposition. Thus.
suppose We asks matter infinitely divis-
ible or Is it not' II we say 1t Is. we cannot
Shtpk al INF 4.
may be stated In words is really unthink-
able.
If VIC say there Il n limit the ultimate
atom-then, az all size il comparative wo
oan imagine a being 20 whom thus atom
seems Is large As an apple or even n house
does to us; and we then find il quite UNI
thinkabe that this mass OF matter should
be in its nature absolutely inl.vi9ible even
by an infinite force. Ii follows that all
explanations of phenomena can only bs
partial explanations They can inform Us
OF the last change or the last series ~
changes which brought about the actual
conditions now existing. and they can often
enable VA TO predict future changes to a
limited extent: hu; ! IA the infinite pa-t
and the remote 'u' Ie are alike beyond
our powers. Yet ia" explanations that
the theory Of evolution gives us are none
the less real and none the less important.
especially when We compare it~ teachings
with the wild guesses or thetotal ignorance
OF the thinkers OF earlier ages.
rRk RIsR AND PROGRESS or THE IDEA or
EVOLUTION.
II We trace, however briefly. the gradual
development Of knowledge and SPECULATION
on this subject, we shall perhap, appre.
cate more fully the advance We have really
MADE during the present century.
The first speculation, on the nature and
source OF the phenomena of the universe Of
which We have any knowledge are those Of
the early Greek philosophers such as
Thaes, Anaximander, Anayaynras AMI