People today seem surprised that a scientist could be a believing Catholic,
let alone 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 of 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 1920’s and 1930’s.
He thought deeply throughout his life about the role of God in the creation of the universe.
In this video, we’ll go over just one example from his remarkable body of work.
In 1931, Lemaître produced a typewritten draft of a paper outlining a theory about the beginning of
the cosmos—what would come to be known as the Big Bang. The finished paper has since become
one of the most important works published in the 20th century about the origins of the universe,
and astronomers today regard it as the foundation for everything we are doing in cosmology.
Lemaître was preparing to send his manuscript to the famous journal Nature.
In a scientific paper like that, one would not expect his views on God to intrude. And yet,
his draft contains an extra sentence at the very end—one
that does not appear in the published paper—that he crossed out with a pencil.
It reads: “I think that every one who believes in a supreme being supporting every being and every
acting, believes also that God is essentially hidden and may be glad to see how present
physics provides a veil hiding the creation.” This single sentence is loaded with information
on Lemaître’s views of the nature of God and His role as Creator. Let’s try to unpack it.
Lemaître thinks of God as hidden, and he was not the first to say that. The Judeo-Christian
concept of the hidden God goes back to a verse in chapter 45 of Isaiah.
But here, Lemaître takes it one step further and suggests that the physics itself
hides the act of creation. This is not an entirely religious or philosophical view. It
may just be Lemaître’s lyrical way of expressing what is generally accepted about the Big Bang:
that one cannot use physics to learn what happened in the cosmos “before” the Big Bang.
Indeed, in some views, time itself began as part of the Big Bang.
Such an idea, without the astrophysics involved,
goes back to St. Augustine in the early 5th century. The famous scientist Stephen Hawking,
an atheist, cites it as well. Lemaître himself asserts this idea earlier in his Nature paper.
Elsewhere, he says, “Any preexistence of the universe has a metaphysical character.
Physically, everything happens as if the theoretical zero was really a beginning.”
Now, let’s return to the first part of Lemaître’s redacted sentence from the Nature letter,
where he refers to God as “supporting every being and every acting.” This important
excerpt reveals his understanding of Aquinas’s view of God as pure act.
For Lemaître, God is not a clockmaker, a disengaged creator who
starts the mechanisms of the cosmos and then leaves the scene. Instead,
he very much holds the view of God espoused by St. Thomas Aquinas (and also by Aristotle):
that God is the source of the actuality by which the universe exists at every moment.
Let me break this down for you. Aquinas saw the world as divided between potency
and act or actuality. The things around us in nature are not only what they actually are,
but also what they can be. A pot of water on the stove is actually cold and potentially
hot. But once it is on a hot burner for some time, the potentiality to be hot becomes actualized.
Aristotle realized that everything that changes goes from potentially being something
to actually being something. But, why does the potentiality of things become actual? After all,
potentiality does not realize itself on its own. To answer this question, Aristotle and Aquinas
argued that the influence of act on something potential could not run backwards infinitely.
There cannot be an infinite chain of things where each is actualized 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 Aquinas did, is through the concepts of essence and existence,
or being. One can readily describe the essence of a human, or of a unicorn, but
neither necessarily exists. Indeed, of the two, only the human truly exists as a material being.
Thus, the essence of something, and its existence, are distinct.
Whatever gives the human existence must itself be given existence,
and so forth, until one arrives recursively, according to Aquinas,
at pure being: something whose essence is existence itself. And that, Aquinas says,
is the God who revealed Himself in the second chapter of Exodus to Moses as: I AM that AM.
The subtlety here in Aquinas’s reasoning—and this is crucial—is
that the ordering is not in time (this led to that which led to another thing, etc.):
it is hierarchical. So, all of material reality, everything that participates in existence,
must be sustained at every moment by pure being, pure act—that is, by God. And this is
exactly what Lemaître says: “a supreme being supporting every being and every acting.”
To me, it is clear that Lemaître’s view of God is the Thomistic view, the God who lends existence to
everything all the time, who creates in a timeless fashion ex nihilo: from nothing.
And so, in that view, Lemaître’s Big Bang is not the creation of everything, which happens
timelessly in God’s eternal now, but the beginning of the temporal evolution of the universe—just
as the north pole is the spatial origin point from which one moves progressively southward
on a sphere, but is not the origin of that sphere in terms of creation.
Lemaître himself was somewhat elusive on this point, saying, “We may speak of this
event as of a beginning. I do not say 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 if it was really a beginning or rather a creation, something started from nothing, is a
philosophical question which cannot be settled by physical or astronomical considerations.”
In his own lifetime, Lemaître was rewarded for both his scientific accomplishments and 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 named a Prelate of the Papal Household
by Pope John XXIII, thereby earning him the title of Monsignor.
In all that he did, throughout his whole life, Georges Lemaître saw the harmony between our
scientific inquiry into the nature of the cosmos and our worship of the God who created it all…
and us. As Lemaître said in accepting the Francqui Prize, “Science is beautiful;
it deserves to be loved for itself, as it is a reflection of God’s creative thought.”
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