The astrophysicist Fred Hoyle wrote that the "chance that higher life forms might have emerged in this way [evolution by natural selection] is comparable to the chance that a tornado sweeping through a junkyard might assemble a Boeing 747 from the materials therein." Is this criticism based on an accurate understanding of how natural selection works?
No, this criticism actually shows two common misunderstandings of evolution.
Firstly, while chance and randomness are involved in the evolutionary history, evolution itself is not merely a random process. Natural selection is constantly taking place so that individuals with characteristics that may enhance their probability of survival and reproduction in a certain environment are more likely to pass on their genes to the next generations. There exists a selective force that is locally directional, with a pressure towards higher adaptiveness in that particular environment (e.g. deeper beaks in Darwin’s finches during drought).
Secondly, the evolution of complex organs like eyes or even “higher life forms” in general is a very slow and gradual process, instead of being the result of a sudden, random mutation or variation. Evolution of such complex structures can only arise through the gradual accumulation of small variations across a long period of time, with all the intermediate steps favored by natural selection.
To conclude, unlike assembling a Boeing 747 out of junk merely by chance at a sudden, the evolution of “higher life forms” is a slow and gradual process that takes place by accumulating the adaptive variations through natural selection over millions of years of time. Also, there exists numerous intermediate life forms in the history of evolution. It is only with the mechanism of descents with modification and “life” being “favored” by natural selection that “higher life forms” can evolve, because of their higher adaptiveness to the environment throughout the history. Therefore, that criticism is based on some misunderstandings of the theory of evolution and is not a valid argument against evolutionary theory.