“One cannot understand modern physics,” a possibly wise particle physicist said to me some years ago. I took him at his word.
I could believe him because he was teaching particle physics in the University of Toronto. You probably need qualifications for that job, I reasoned, and to get them I’ll bet you have to pass a test.
But understanding something, and passing a test are, as many students learn eventually, two different things. And one may be incompatible with the other.
An example of this from physics might be the “Big Bang” theory, which (for the foreseeable future) will defeat all other accounts of cosmic origin for plausibility. Like any alternative cosmic origin theory, it doesn’t actually tell us how the world began. It cannot pretend to be “settled science”; non-scientists do the pretending.
What came before the Big Bang? Religious (not scientific) faith may suggest that God was there before; and was “the singularity.” But God doesn’t fit into a singularity; it’s just a word.
The truth is that we haven’t, and can’t have a clue, as to what if anything came before. It is not only undetectable. It is unimaginable.
Monsignor Georges Lemaître, the Belgian Catholic priest and ingenious physicist who postulated the Big Bang, had to deal with a pope who was a science enthusiast, and who bought into Lemaître’s theory too quickly and too grandly. Lemaître himself had to talk Pius XII down from his excitement, for he thought (as many still do) that man was on the verge of proving God, through science.
Lemaître would admit that his cosmic theory was in harmony with the account in Genesis, but he knew that harmony is not identity. The First Vatican Council had dealt with this, in its presentation of fides et ratio. It had condemned rationalism, in the absence of faith; but it had also condemned fideism, which is faith without reason.
This latter is the more common error today, which is why, I suspect, people including scientists like to fall for it, without thinking. But like other heresies, one may tumble off either side.
Msgr. Lemaître – a truly remarkable man, of broad cultural accomplishment, as one learns from the excellent biography by Dominique Lambert  – was an equal-opportunity fixer of mistakes. It wasn’t only the pope whose Catholic doctrine he corrected. He also famously corrected the physics doctrine of Albert Einstein.
Einstein’s static universe was inconsistent with Einstein’s own relativist theory. Lemaître showed him that it could only be consistent with an expanding universe. It took Einstein some time to realize that he was wrong; whereas Pope Pius XII got the Catholic point fairly quickly.
He, Pope Pius XII, had lapsed into “concordism,” as we sometimes call it today; one of the milder though still potentially mortal of Catholic heresies. This is the belief that the natural world, as described in Scripture, can be described scientifically in the same way.
It is a constant temptation (like other heresies) to imagine that God, as ultimate inspirer of the Bible, was anticipating developments in later centuries, and leaving hints for future science nerds to test in their laboratories.
God, I think we could say, is not so nerd-friendly. Supernatural truths are not identical with natural truths, though they may be harmonic. Indeed, Scripture goes so far as to suggest this, I realize, in reading Isaiah.
But this is an affect of poetry, rather than of science.
To say that Scripture is a work of poetry is not to demean it, incidentally. For poetry can be even less accessible than science to the person educated under modern conditions. We do not even begin to appreciate its function in our understanding of the world God created.
Poetry is not “just words” as St John the Evangelist is not just prattle. (There are so many big things that we shall have to learn again.)
Even what is literally true may be raised to the poetic, in the presence of the divine. Christ Himself was, at one and the same moment, a Palestinian peasant and Our Savior. He was not Himself reducible to biological factors, as neither are we. The “person’ we describe in language, is not a simple material object, and cannot be dismissed as if he is. The full description of him must finally pass beyond science, as most scientists understand.
And so it is with the universe and its Big Bang. Lemaître’s description of the “infinitesimal cosmic egg” out of which it sprang may serve as metaphor, and through mathematics as a form of poetry, additional to the account of Genesis. It would do so even if Genesis were accepted as literally true: for scientific truth would still be another thing.
But what “actually” happened at the beginning of Genesis is something that, in our present and natural condition, we cannot know, because, of course, we were not here when the universe was being formed.
And faith does not require us to pretend that we know what we don’t. Only a fideist would go so far, and trip into the world of concordism.
For let us be Catholic for a moment. God does not expect us to lie in the cause of religion, or in any other cause. We cannot claim, or timidly imply, a knowledge that is beyond our means. We accept tradition, and value it on its own terms, which are extravagant enough – neither discounting nor inflating its claim upon us.
If, as Christians assert, there is a God who can be glimpsed in the dead and living Jesus Christ, we accept His divinity, and authority. But we do not assert that we are Christ, if our faith is correctly deposited.
Thinking back on that physics professor, whose job was to teach what he did not completely understand, I find a certain kind of sense. We must remain modest when confronted with supernatural things. And like Lemaître, we should know what we can’t know.
*Image: Msgr. Lemaître with physicist Arthur S. Eddington aboard the ship returning from the 6th General Assembly of the International Astronomical Union, in Stockholm, August 1938 [UCL Archives (Catholic University of Louvain, Belgium)]. Eddington was the first to correctly speculate that the energy source in stars is the nuclear fusion of hydrogen into helium.
You may also enjoy:
Michael Baruzzini’s Introducing the Hubble–Lemaître Law 
Brad Miner’s The Big Noise and the Stars