Young Darwin took a voyage aboard the Beagle in 1831, providing him with the observational material to put forward his infamous theory of evolution. He writes about this in both Origin of Species and The Descent of Man.
Darwin's Theory of The Essence of a Thing
Before Darwin, Plato and Aristotle both believed that everything (be it metal, animal or plant) can be seen as having an essential quality, that makes it what it is, and accidental quality, that do not change the things identity. This was the standard theory. In the natural world, then, a dog is a dog and a horse is a horse. One knows that a dog is not a horse because of its fundamental qualities, or its 'essence'. Even though there are differences between different kinds of dogs, and even individual dogs, these are 'accidental' and do not detract from identity as a dog.
Philosophers have always pondered how to account for these essences; where did they appear from? Before Darwin, it was thought that there must have been a grand designer. Darwin, however, would show that these complex designs could arise naturally, without the need of a designer or a designers blueprint.
The Background of Evolutionary Theory
This started with Thomas Malthus, whose work was on population explosion. He noted that to avoid extinction, a species must continually expand its population. However, natural resources, he argued, would inevitably run out for any given species. Therefore, according to Malthus it is necessary for some species to die while others survive.
Darwin's theory of evolution begins with the question; what distinguishes which species live and which die out? He notes, 'If... organic beings vary at all in the several parts of their organisation... I think that it would be a most extraordinary fact if no variation had ever occurred useful to each beings own welfare... if variations useful to any organic being do occur, assuredly individuals thus characterised will have the best chance of being preserved in the struggle for life; and from the strong principle of inheritance they will tend to produce offspring similarly characterised. This principle of preservation, I have called... Natural Selection.'
Darwin's Natural Selection
Natural Selection, then, has two components. The first is the minor differences that exist between individuals and the second the principle of inheritance that passes these differences from generation to generation of any given species. Darwin noted that big geographical or climatic changes may be the difference between life and death to any number of species in the region in which it had occurred.
Darwin went on to show that the 'essential' differences between any given species are nothing more than 'decent by modification'. In other words, what looks like design is, in fact, just the survival of inheritable qualities.
Although critics have complained that Darwin's evolutionary theory is incapable of refutation, Darwin argued that if it could literally be disproved by way of scientific example, his theory would completely break down. No alternative theory has so far been able to provide the evidence to meet his challenge.
Sources:
Philosophy: 100 Essential Thinkers, Philip Stokes. Arcturus Publishing, Copyright 2002.
The Book of Dead Philosophers, Simon Critchley. Granta Books, Copyright 2008.
Beth Walley - I am an individual UK-based freelance writer, who has always harboured a great love of books; encompassing an obsessive fascination with ...
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