In 1953 British astrophysicist Fred Hoyle calculated that there were nuclear resonances involving the nuclei of atoms of helium, beryllium, and carbon. This was a bit surprising because the year before William Alfred Fowler’s lab in California had published their failure to detect signs of an internal energy level in the carbon nucleus near Hoyle’s prediction. Hoyle then did something cocky: he went to California and knocked on Fowler’s door to talk about it. Fowler’s people were doubtful, but a new graduate student named Ward Whaling volunteered to run the experiment, and he confirmed Hoyle’s exact prediction.
Sadly, Fowler would be the only one to win a Noble prize for this work.
Hoyle was extremely excited by his original calculations because they explained why there is carbon-based life. There is no other way to explain the amount of carbon in the universe than this triple alpha process: one helium nuclei is also known as an alpha particle, so two helium-4 nuclei (each with 2 protons and 2 neutrons) fuse to make beryllium-8, and then the third helium-4 fuses with the beryllium-8 to make carbon-12. But what Hoyle also realized is that the triple alpha process was dependent on the oxygen nuclei not having resonance, for if it did most of the carbon-12 would be fused with a fourth helium-4 to make oxygen-16. There is only a narrow window where the nuclear energy required is high enough to make carbon but not too high to destroy it.
These resonances are controlled by two fundamental constants of nature: the fine structure constant (which quantifies the strength of the electromagnetic force), and the strong coupling constant (which quantifies the strength of the strong nuclear force that holds nuclei together). These constants are dimensionless, meaning they have no attached units of measurement. Hoyle then calculated that if the fine structure constant differed by 4% from its value, or the strong constant by 0.4%, then there would be little carbon or little oxygen and we would not be here.
This is now seen as an example of the fine tuning of the universe that appears necessary for intelligent life.
Other examples exist.
For example, the gravitational constant determines the interior pressure of stars. Too high and stars burn out before enough time has elapsed for life to evolve on their planets. Too low and they never ignite to warm those planets; in fact the planets themselves might form too slowly.
Another is the mass ratio of the proton to the electron. If electrons were just 10% more massive their orbits in their electron shells would be unstable and molecules would never form.
These and other examples of fine tuning became the basis of the so-called anthropic principles. They are not theories, but rather axioms, in a sense parts of the checklist of scientific thinking much like Occam’s razor or the Copernican Principle. Some scientists dismiss them as tautologies, while others see them as more evidence of the important role of the observer a la the Copenhagen interpretation.
Or, as Freeman Dyson put it “…the universe in some sense must have known we were coming.”
Another consequence of the discovery of fine tuning is a revival of a religious defense of intelligent design.
Broadly speaking, intelligent design has always been a component of theistic thinking. It predates Christianity, and Christians have always engaged in it. One variant became known as the watchmaker argument, at least since there have been watchmakers.
There was another less worthy reason for the revival of intelligent design. In 1987 the U.S. Supreme Court ruled in Edwards v. Aguillard that creationism could not be taught as science in public schools because it was a religious argument and thus a pseudoscience. It was this case that enshrined Karl Popper’s falsifiability criterion into U.S. constitutional law. Creationists responded with ‘Intelligent Design’ as a kind of repackaged creationism, and defenders of the scientific method responded, quite properly, by attacking ‘Intelligent Design’ as a pseudoscience.
However, there is a problem. Intelligent design is a pseudoscience only if it is presented as a science. As a philosophical or theological position it clearly is not a pseudoscience. In fact, intelligent design is clearly the favored Biblical position, though there are many versions, including some that cannot be called creationism at all. Even worse, in their zeal some critics of the pseudoscience now attack any use of any scientific observation or discovery in support of any intelligent design argument. This is hardly proper, anymore that it would be to, say, attack incidental use of science in children’s literature. In their zeal to defend science from pseudoscience, we find that some critics would deny the legitimate use of science in religious debate. By doing this these critics are enabling the competing pseudoreligion of scientism.
This growth of scientism is a major reason why we have shifted from a more-tolerant pluralistic society to a less-tolerant secular society, and for the coarsening of our public discourse. We hardly notice because it’s simply in the air we breathe. All are reasons for keeping the demarcations of science in mind when evangelizing, or when doing science.