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The Science of Evolution
Were We Bound To Evolve? --
The Role of Random and Non-Random Factors in Evolution
While human beings are one particular result of billions of years of
step-wise biological evolution (and clearly not the special and independent
Creation of a supernatural force or god), it is not the case that evolution
was inevitably "bound" to "lead up to" the emergence of the human species.
Populations of living organisms evolve through a complex combination and
interplay of both "chance" and "necessity": first of all, random
("chance") factors such as mutations, recombinations and genetic drift, lead
to a continual re-shuffling of the deck of cards which makes up the total
genetic variation in a population and which serves as the raw material of
evolutionary change; but, then, on the basis of that randomly produced
variation, natural selection proceeds to very much non-randomly sort
out some of the resulting features of organisms in relation to the
demands and challenges of a given external environment. This process can
proceed for a time in a certain specific "direction," as when populations of
organisms are becoming increasingly "adapted" to a certain set of
environmental conditions. But it is important to realize that not all
evolutionary modifications represent adaptations, that there are no permanent
and "set" directions in the evolution of life, and that evolutionary trends
and directions can change course (or even completely reverse themselves) as
conditions change.
The Creationists like to say that evolutionists believe that all the
different life-forms, including human beings, came about "purely by accident."
But all this shows is that they don't understand that evolution comes about
through a combination of both random and non-random factors: in the
evolution of human beings or any other species, natural selection non-randomly
"favored" certain step-by-step modifications (which happened to have emerged
on the basis of random variation) whenever such a modification conferred a
distinct reproductive advantage on individuals which had that new feature.
This is the part of the evolutionary process which is not "accidental" (though
it still doesn't involve any supernatural guidance or selection of any sort).
But then again there were never any guarantees that any particular
forms of genetic variation would arise in the first place; that they would not
be extinguished almost as soon as they had emerged; or even that a given
species as a whole would avoid extinction in a given external environment. In
short, the evolution of human beings or any other life-form is not just
the result of a series of "accidents" (though accidents do play an important
role in evolution), but neither did it require, or involve, the intervention
of any outside supernatural forces.
And, while human beings are definitely the product of natural biological
evolution, evolution could just as easily not have led to the emergence
of human beings at all!
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