II. The Evolution of Complexity

So, naturalists observe, a flea
Has smaller fleas that on him prey;
And these have smaller still to bite ’em;
And so proceed ad infinitum.

-Jonathan Swift

At all scales, the natural world bristles with complexity; fleas upon fleas, bacteria upon fleas, complex molecules in biochemical pathways, all of which display complex dynamic relationships. The staggering diversity and breathtaking complexity of living systems only increases when attempts are made to reduce them to their substituent parts. 

The 'Watchmaker Argument' posits that this complexity could not have come about without an intelligent designer; that if we were to stumble upon a watch in an empty field, we would not suggest that the complex watch, with all its gears and springs, would have come to exist on its own. However, as counterintuitive as it may seem, lines of evidence from diverse fields of science indicate that all the complexity in the natural world is generated by Darwinian evolution.