(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)
After Darwin published his book On the Origin of Species in 1859, large numbers of people were convinced in a very short time by his arguments, although full acceptance of the mechanism of natural selection took longer. But the idea of evolution had been in the air for some time. Why didn’t people before him see what Darwin and his co-discoverer Alfred Russell Wallace saw, since they had access to much of the same evidence that he had?
A possible reason is because the theory of evolution also required a Gestalt-type switch. People had been viewing the world through a prism of Platonic ideal forms. In the Platonic view, real objects are approximations to their ideal forms and it is only the ideal forms that matter and from which we get true information. So for example, for any triangle that we draw on paper, the angles will not add up to exactly 180 degrees because of the inevitable imperfections of our drawing and the inaccuracies of our measuring instruments. But the angles of all ideal triangles (that we can only conceive of in our minds) will always add up to 180 degrees, and it is the properties of that ideal form that is important to understand, not our real-life approximations.
While this way of looking at things is perfectly suited for mathematics, it leads people hopelessly astray when applied to biology. In the case of biological organisms, the Platonic model translates into thinking of each species as having an ideal form and of real organisms as just approximations that can and do deviate from the ideal in unimportant ways. So real chickens, with all their variety, are just imperfect manifestations of the ideal, perfect chicken that we can only conceive of in our minds. It is this perfect chicken that we need to study to understand what makes a chicken a chicken, the essence of chickenhood.
But the problem is that the ideal perfect chicken will necessarily always remains the same and cannot evolve into anything else, just like a triangle will not become a square nor will the sum of its angles slowly change with time. Platonic thinking rules out change but is perfectly consistent with the idea of a god creating every species as perfect unchangeable beings and part of a grand plan.
Darwin and Wallace both realized that it is the real forms of organisms that are important, not its idealized version, and furthermore that there are no ideal forms in biology. There is no idealized chicken. The variations found in real chickens, rather than being a nuisance detracting from our understanding of the ideal chicken, actually contain the key to understanding the nature of chickens and how they and other things can change. This shift in perception made the variations in a species central to our understanding, and not peripheral.
The likely reason that Darwin and Wallace may have been able to make the switch is because they spent some time traveling to other parts of the world and saw much more of the variety of life than those who stayed pretty much in one locality. Darwin’s voyage on the Beagle confronted him with so much new information about the diversity of life in so many new locations that it forced him into new ways of thinking. Alfred Russell Wallace also had his epiphany while travelling through Asia collecting biological specimens that were exotic and new to him.
Once Darwin and Wallace had made this switch, things started falling into place. They realized that if one adds up these small variations cumulatively over a long time, then even though each one is so small that it cannot be observed with the naked eye or even in one’s lifetime, it can add up to huge changes, resulting in the emergence of new species, something that was ruled out by Platonic thinking.
Two things stood in the way of making such an idea workable. It seemed to require an inordinate amount of time, much longer than people at that time thought the Earth had existed, and it lacked a plausible mechanism for species change. An obvious objection to their model that they needed to find an answer for was why should the variations in organisms cumulatively add up to result in large changes? Why could they not simply vary randomly leaving, on average, no net change?
This is where other factors can play a role in making a Gestalt switch in perception.
Next: The key steps in ‘seeing’ evolution
POST SCRIPT: Jon Stewart parodies Glenn Beck
This clip has been all over the political blogs but it is well worth seeing. Utterly hilarious.
|The Daily Show With Jon Stewart||Mon – Thurs 11p / 10c|