Georges Lemaître: The Priest Who Discovered the Big Bang w/ Prof. Jonathan Lunine (Aquinas 101)

Nowadays people seem surprised that a scientist could be a believing Catholic, much less a

priest

. Some have even suggested that believing scientists only pretend to believe, to fit in. But did you know that the father of the Big Bang model for how the universe began was a Catholic

priest

? In fact, this man's faith may have instilled in him a deep sense of wonder and inspired his groundbreaking research into the origin of the universe. Georges Lemaître was a Belgian Catholic priest and astronomer who made an extraordinary number of contributions to our understanding of the cosmos in the 1920s and 1930s.

He thought deeply throughout his life about God's role in the creation of the universe. . In this video, we'll go over just one example of his remarkable work. In 1931, Lemaître wrote a typewritten draft of a paper outlining a theory about the beginning of the cosmos, what would become known as the Big Bang. The finished paper has since become one of the most important works published in the 20th century on the origins of the universe, and is considered by today's astronomers to be the foundation for everything we do in cosmology. Lemaître was preparing to send his manuscript to the famous journal Nature.

In a scientific article like that, one wouldn't expect his views on God to intrude. And yet his draft contains an extra sentence at the end (one that does not appear in the published article) that he crossed out with a pencil. He says: “I believe that anyone who believes in a supreme being that sustains every being and every action also believes that God is essentially hidden and can rejoice in seeing how present-day physics provides a veil that hides creation.” This single sentence is loaded with information about Lemaître's views on the nature of God and his role as Creator.

Let's try to unzip it. Lemaître thinks that God is hidden and he was not the first to say so. The Judeo-Christian concept of the hidden God dates back to a verse in Isaiah chapter 45. But here, Lemaître goes a step further and suggests that physics itself obscures the act of creation. This is not an entirely religious or philosophical view. It may simply be Lemaître's lyrical way of expressing what is generally accepted about the Big Bang: that you cannot use physics to learn what happened in the cosmos “before” the Big Bang. In fact, according to some opinions, time itself began as part of the Big Bang.

This idea, without astrophysics involved, dates back to St. Augustine in the early 5th century. The famous scientist Stephen Hawking, an atheist, also cites it. Lemaître himself affirms this idea earlier in his article in Nature. Elsewhere, he says: “Any pre-existence of the universe has a metaphysical character. “Physically everything happens as if the theoretical zero were really a beginning.” Now, let's return to the first part of the sentence written by Lemaître from the Nature letter, where he refers to God as "the support of every being and every action." This important excerpt reveals his understanding of Aquinas's view of God as a pure act.

For Lemaître, God is not a clockmaker, a disconnected creator who sets the mechanisms of the cosmos in motion and then leaves the scene. Instead, he largely holds the view of God adopted by Aquinas (and also Aristotle): that God is the source of the reality by which the universe exists at every moment. Let me explain this to you. Thomas Aquinas saw the world divided between potentiality and act or actuality. The things that surround us in nature are not only what they really are, but also what they can be. A pot of water on the stove is actually cold and potentially hot.

But once it's on a hot burner for some time, the potential for being hot is actualized. Aristotle realized that everything that changes goes from being something potentially to being something in reality. But why does the potentiality of things become actual? After all, potentiality does not realize itself. To answer this question, Aristotle and Aquinas argued that the influence of the act on something potential could not regress infinitely. There cannot be an infinite chain of things where each one is updated by something else. There must be some ultimate source of act, something that is itself pure act, without any potentiality in it.

And that, they argued, is God. Another way to look at this, as Thomas Aquinas did, is through the concepts of essence and existence, or being. You can easily describe the essence of a human or a unicorn, but neither necessarily exists. In fact, of the two, only the human truly exists as a material being. Therefore, the essence of something and its existence are different. Everything that gives human existence must receive existence, and so on, until one reaches recursively, according to Thomas Aquinas, pure being: something whose essence is existence itself. And that, says Thomas Aquinas, is the God who revealed himself in the second chapter of the Exodus to Moses as: I AM that I AM.

The subtlety here in Aquinas's reasoning—and this is crucial—is that the order is not in time (this led to what led to something else, etc.): it is hierarchical. Thus, all material reality, everything that participates in existence, must be sustained at all times by the pure being, the pure act, that is, by God. And this is exactly what Lemaître says: “a supreme being that sustains every being and every action.” To me, it is clear that Lemaître's vision of God is the Thomistic vision, the God who brings everything into existence at all times, who creates in a timeless way ex nihilo: from nothing.

And so, from that point of view, Lemaître's Big Bang is not the creation of everything, what happens timelessly in God's eternal now, but the beginning of the temporal evolution of the universe, just as the north pole is the point of spatial origin from which one moves. progressively southward in a sphere, but it is not the origin of that sphere in terms of creation. Lemaître himself was somewhat elusive in this regard and said: “We can speak of this event as a beginning. I'm not saying a creation. Physically it is a beginning in the sense that if something happened before, it has no observable influence on the behavior of our universe...

The question of whether it really was a beginning or rather a creation, something that started from nothing, is “a philosophical question that cannot be resolved by physical or astronomical considerations.” During his lifetime, Lemaître was rewarded both for his scientific achievements and for his work as a priest. As a scientist, in 1934 he won the lucrative Francqui Prize for his research, and he was nominated for that honor by none other than Albert Einstein! As a Catholic priest, in 1960, Lemaître was appointed Prelate of the Papal Household by Pope John XXIII, earning him the title of Monsignor. In everything he did, throughout his entire life, Georges Lemaître saw the harmony between our scientific research into the nature of the cosmos and our worship of the God who created everything... and us.

As Lemaître said when accepting the Francqui Prize: “Science is beautiful; It deserves to be loved for its own sake, as it is a reflection of God's creative thought.” For readings, podcasts and more videos like this, visit Aquinas101.com. While you're there, be sure to sign up for one of our free video courses on Thomas Aquinas. And don't forget to like and share with your friends, because what you think matters!