Scientists go about trying to collect evidence that can be brought to bear on disputes between rival theories. If I accept the abiogenic theory of petroleum origins, whereas you accept the biogenic theory, then there is a simple way we can settle our dispute. We can try to find evidence of petroleum originating deep in the Earth’s crust, in a layer that cannot plausibly contain fossil deposits. This evidence would favour the abiogenic theory over the biogenic theory, and our dispute would be settled. But of course, there is more to science than just collecting evidence. Scientists don’t just collect evidence and write up papers for peer review; they also come up with the theories in the first place. And while the quest for relevant evidence is largely methodical, rational and logical, the creation of a new theory is largely spontaneous, whimsical and imaginative.
Here’s my favourite example: In 1948 Thomas Gold, Hermann Bondi and Fred Hoyle together published papers on their “steady state” theory of the universe. The steady state theory of the universe charges that the although the universe is expanding, the average density of matter in the universe remains the same, as new matter is constantly being generated to fill the gaps in the expanding universe. The theory was more or less abandoned after the discovery of cosmic microwave background radiation in 1964, which was predicted by the big bang theory, and not by the steady state theory.
How did these men come up with their new theory? One day Gold, Bondi and Hoyle were a bit bored, and they decided to go to a movie. The movie they went to was a British horror film called The Dead of Night, in which a young man has some terrifying experiences and is just about to be killed, when luckily he wakes up to find that it’s all been a dream. He gets out of bed and starts to go about his day, but then experiences from the nightmare world begin to happen to him all over again. Ultimately, the audience knows that this is a terrible endless cycle. The movie changes, and yet in some sense it always stays the same. Upon returning to their college hall that night, Thomas Gold blurted out “What if the universe was like that?” From that point on through the night, the men devised an answer to that question. They figured out what it would have to be like for the universe to resemble a British horror film.
Here’s another example, that may surprise some: The Victorian “catastrophist” geologists accepted that a devastating global flood had covered the Earth at some point in its history. The inspiration for this theory was the Biblical fable of Noah’s flood. This might surprise you if you think that science self-imposes a methodological naturalism having no time for theistic or religious explanations. But methodological naturalism is irrelevant when it comes to the inspiration—the Eureka moment—behind the development of a scientific theory.
This one is a classic: August Kekulé famously devised his theory about the chemical structure of benzene after dozing off in front of the fire, and having a half-waking vision of a golden ouroboros. This vision was structurally identical to the benzene molecule.
And lastly but not leastly: Kary Mullis discovered Polymerase Chain Reaction, or PCR, while apparently under the influence of LSD, driving through the deserts of central California in a confused state. I quote him:
My little silver Honda’s front tires pulled us through the mountains. My hands felt the road and the turns. My mind drifted back into the laboratory. DNA chains coiled and floated. Lurid blue and pink images of electric molecules injected themselves somewhere between the mountain road and my eyes.
The discovery of PCR, which is the primary method for amplifying bits of DNA used in laboratories today, utterly changed modern biology, and as soon as Mullis realised the magnitude of his discovery, he knew he had changed the course of, not only his own life, but of the history of humanity. He continued on:
I didn’t sleep that night. The next morning I bought two bottles of Navarro Vineyards Pinot Noir, and by mid afternoon had settled into a fitful sleep. There were diagrams of PCR reactions on every surface that would take pencil or crayon in my cabin. I woke up in a new world.
(quotes taken from Mullis, 2009)