Navigating the relationship between science and faith can be something of a minefield. Fr Georges Lemaître (whom I wrote about last month) was not too pleased when Pope Pius XII suggested that his cosmological theory had succeeded in bearing witness to the august instant of the primordial Fiat Lux (“let there be light”) at the beginning of time. Lemaître was right to be concerned.
Centuries earlier, St Thomas Aquinas recalled a thought experiment from the Jewish philosopher Moses Maimonides to explain why it is impossible to prove that either the world had a beginning or was eternal. In this thought experiment, a boy whose mother died in his infancy is raised on a solitary island where there are no other children. When the boy reaches the age of reason, he asks someone whether and how people are made. When an account of human generation is explained to the boy, he rejects it as absurd. After all, from his limited experience, he is convinced that people need to breathe, eat and expel waste in order to live, and so understandably the boy thinks no one would be able to survive even one day, let alone nine months in their mother’s womb.
St Thomas Aquinas says that those who try to show that the world had a beginning or try to show that the world is eternal are like this boy, who is unable to draw the right conclusion from the way things appear to be in their fully generated state. So although it is an article of the Catholic faith that the world did indeed have a beginning, we should avoid trying to prove this because any purported proof will be unsound, and unsound arguments are a mockery of the faith rather than a confirmation of it.
Nevertheless, in our attempt to avoid the pitfalls of too close an association between science and faith, we also need to avoid the other extreme in which science and faith have absolutely nothing to say to each other. Granted, we will not learn much about Einstein’s theory of general relativity from reading the book of Genesis, nor should we be able to deduce from Einstein’s theory that in the beginning God said, “Let there be light.” But if we believe that God did say this, then we must reflect on what this means and allow this meaning to shape how we see reality. It is interesting to note that both theists and physicists are fascinated with light. Theists speak of light in so many different ways: the light of our eyes, the light of our minds, the light of faith, the light of glory, etc. This language of light suggests that there is an intelligibility to reality. Reality is not absurd – all things will ultimately make sense if we see them in the right light.
The conviction that reality is intelligible is also a guiding principle in science, but for the physicist, physical light itself is a guiding principle. Indeed, some of the most revolutionary insights about physical reality have come about through a careful study and speculation on the behaviour of light. It was the 19th-century physicist James Clerk Maxwell who speculated that light waves were fluctuations in electric and magnetic fields. His idea led to the discovery of radio waves, which have transformed the modern world. At the turn of the 20th century, the German physicist Max Planck gave birth to quantum physics by trying to explain how the light frequencies emitted from hot bodies were related to their temperature. A few years later, in 1905, Einstein explained how light causes an electric current to flow when it is shone on certain materials. He did this by making the radical suggestion that light is composed of particles despite it also being a wave.
That same year, Einstein made an even more radical suggestion claiming that space and time are not absolute, but rather will be measured differently depending on how fast one is moving. He drew this conclusion because it enabled him to explain how light always seems to travel at the same speed. This insight led him to conclude that mass is convertible into energy, enabling humanity to harness nuclear power, for good or ill. And after speculating about how gravity affects light, Einstein concluded that space-time must be curved. It is this insight that Lemaître developed in his theory that is now known as the Big Bang.
So as a guiding principle, physical light has led physicists a long way. But it does have its limits. If all we have to go on are the mathematical formulae of quantum physics, then reality as a whole will seem very bizarre, if not unintelligible. But if we believe in God’s Fiat Lux, we will never be satisfied with unintelligibility. We will keep searching for that higher light which reveals the beauty and intelligibility of the whole of God’s creation.
This article first appeared in the Easter 2022 issue of the Catholic Herald. Subscribe today.
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