In Darwin's Shadow: The Life and Science of Alfred Russel Wallace ...

The Life of Wallace and the Nature of History / 309
Not only does the marvellous structure of each organised being involve the
whole past history of the earth, but such apparently unimportant facts as the
presence of certain types of plants or animals in one island rather than in another,
are now shown to be dependent on the long series of past geological
changes—on those marvellous astronomical revolutions which cause a periodic
variation of terrestrial climates—on the apparently fortuitous action of storms
and currents in the conveyance of germs—and on the endlessly varied actions
and reactions of organized beings on each other. And although these various
causes are far too complex in their combined action to enable us to follow them
out in the case of any one species, yet their broad results are clearly recognisable;
and we are thus encouraged to study more completely every detail and
every anomaly in the distribution of living things, in the firm conviction that
by so doing we shall obtain a fuller and clearer insight into the course of nature,
and with increased confidence that the “mighty maze” of Being we see everywhere
around us is “not without a plan.” 15
Bound Together
On one level Wallace’s entire working career was dedicated to a scientific
understanding of the cause of physical, biological, and social phenomena. He
would not settle for (and by temperament was not comfortable with) leaving
the apparent chaos of nature unaccounted for without at least a rational search
for order—unraveling the maze, discovering the plan. In the physical world,
his analysis of the structure of the earth, solar system, and cosmos in Man’s
Place in the Universe found order in chaos by invoking a higher intelligence,
necessary because of contingency—change one small component in the early
evolution of the universe, and life would have been radically different or,
more likely, nonexistent. Wallace’s replay of the time line of intelligent human
life would necessitate the contingencies of evolution to occur in exactly the
sequence they did in the original sequence: “In order to produce a world that
should be precisely adapted in every detail for the orderly development of
organic life culminating in man, such a vast and complex universe as that
which we know exists around us, may have been absolutely required.” 16 That
requirement was, for Wallace, met by an all-pervading higher intelligence.
In the biological world, of course, his own and Darwin’s theory of natural
selection as the driving mechanism of evolutionary change in the history of
life nearly completely orders the chaotic diversity of nature, as he indicates
in a passage from a letter to his childhood friend Thomas Sims, from the
island of Timor, on March 15, 1861: “It is the vast chaos of facts, which are
explicable and fall into beautiful order on the one theory [natural selection],
which are inexplicable and remain a chaos on the other [the critics of Darwin],
which I think must ultimately force Darwin’s view on any and every reflecting