(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.)

In the history of science, we have often seen a theory being accepted and used over a long period and then replaced with a new one, with the transition occurring over a relatively short time. Sometimes the new theory is fairly simple and we marvel as to why people did not think of it before. For example, the Copernican heliocentric model is not a complicated idea when compared to the previous geocentric model. Similarly Newtonian mechanics can be formulated in terms of laws that are very simple mathematically and easy to understand. The essential ideas of Darwin’s theory of evolution by natural selection can also be stated in a few simple sentences.

All three of these major new theories are of the kind that, if we had lived in the times when their inventors articulated them, we would have reacted exactly like T. H. Huxley, an early convert to Darwin’s theory of evolution, who once he understood how natural selection worked, said “How extremely stupid not to have thought of that!”

So why did it take so long for people like Copernicus, Newton, and Darwin to come along with these new ideas? After all, the ancient Greek and Arab and Chinese civilizations were scientifically advanced. Why did it take over a millenium for us to develop modern science, which can arguably said to begin with Galileo?

This is the topic of study of historians and philosophers of science and they have come up with many factors to explain this phenomenon.

One explanation is, of course, the appearance of new evidence and data. If the new evidence is hard to reconcile under the old paradigmatic theory and causes serious problems for it, that can create an openness to new ideas and trigger the search for new theories. People try to see things in new ways.

Then there are the influences of developments in other areas. Advances in technology often lead to new data that were inaccessible before. The invention of telescopes, for example, allowed for the detection by Galileo of the moons orbiting Jupiter and dealt a serious blow to the geocentric model that said that every celestial body orbited the Earth. It became clear that other celestial objects could be the center of an orbit and thus the heliocentric idea became less outlandish.

Similarly, changes in the political, social, and intellectual climate may makes communities more open to ideas that were unthinkable before. The period we know as the Enlightenment was more open to new ideas and less wedded to religious dogma. Societies that are repressive in general are unlikely to be sources of great new intellectual discoveries.

One has also to take into account individual genius to create the new theory, though the way they contributed is often misunderstood. These geniuses often did not come up with completely new ideas but were able to recognize that the same buzz swirling around them as around others actually fit into a new pattern. Once they articulated that new pattern, others could almost immediately identify it as the right way to see things. But what enabled the pioneers to make that particular leap that eluded others who had access to the same ideas and knowledge?

Thomas Kuhn has argued, especially in his classic work The Structure of Scientific Revolutions, that what happened with these people is similar to the phenomenon known as the Gestalt switch, familiar to all of us in those visual puzzles where we can look at a single image and see it switching between a duck and a rabbit, or between a vase and two people facing each other.

What happens with some scientific revolutions is that what everyone sees as a duck, one person suddenly sees as a rabbit. When they point out to others the new way of seeing the world, the reaction of others is similar to the reaction you get from people who initially saw only the duck (say) but now almost immediately see the rabbit. After the revelation, it is hard for people to imagine how they could not have seen it before because it seems so obvious.

Next: Specific examples of Gestalt-like switches in science

POST SCRIPT: Radio interview about my book

On Tuesday, November 10, I will be interviewed on the Cleveland NPR affiliate station WCPN 90.3 from 9:00-10:00 am on its program The Sound of Ideas. This was rescheduled from last Thursday.

The topic will be my latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom. You can listen online live on its webcast or listen to the podcast after the show.

It is a call-in show: local 216-578-0903 or toll-free 866-578-0903.

That same evening at 7:00 pm I will be speaking to the Center for Inquiry–Northeast Ohio in the second floor reading room of the Maple Heights library 5225 Library Lane, Maple Heights, OH 44137-1291. The event is open and free.