The Catholic Christian Faith is based on faith and reason, not faith alone. And we are obliged by our love of truth to consider and accept any scientific theories that are reasonable, fairly well proven, and not in contradiction to the teachings of Faith. But faith is always greater than reason.
Now a problem arises in modern society, in that many scientists have abandoned faith in their own lives, or, if they have not, they do not permit their faith to have any influence on their science. The result is that science sometimes errs in proposing ideas that are contrary to Faith. Often these ideas are mere hypotheses, unsupported by evidence and scientifically unproven. We should not treat the ideas of science as dogma. A scientific hypothesis with no support should be rejected, if it contradicts faith or reason. And a scientific theory with much support should still not be treated as infallible truth; some points within that theory might in in error, even if the main ideas are true.
There is a scientific hypothesis that the universe was spontaneously created out of nothing, not by an act of God, but by some principle that something can be produced by nothing. Is there any proof of this idea? No; there is no scientific evidence to support it at all. And since we know by faith that God created the universe from nothing, we cannot accept this hypothesis, not even if some scant evidence were presented in the future.
On the topic of evolution, a problem arises among believers. Some points within that theory contradict the teachings of Christianity, especially the creation of humanity by God. So we must reject that point, and any other points that contradict the Faith. But some believers have decided to utterly reject the theory of evolution, because certain few points in the theory are shown to be false by the light of Faith. And that complete rejection of evolution is an error. As believers, we must love truth, including truths shown by the light of reason.
In my view, evolution is a set of ideas, and most of those ideas are well-proven. I see no reason to reject the whole theory. God is Truth, and so we must not reject anything in the theory of evolution that is true. Rejecting truth offends God. My approach to evolution is to reject only certain few points, those that are in irreconcilable conflict with definitive teachings of the Faith.
Now the glass ceiling of evolution is this: the development of species progresses, by evolution but under the Providence of God, so that species advance to a greater degree of complexity and ability. Single cell creatures evolve into multi-cell creatures, and lower life forms evolve into higher life forms. The result is a great variety of plants and animals. But this advancement reaches a limit, one that is not immediately obvious — a glass ceiling. For evolution, even though guided by the loving Providence of God, can never gift a species with an immortal soul, nor with free will and the ability to exercise abstract reasoning. The lower animals, especially those that are most advanced, can exercise some type of thinking, which I term pre-rational thinking. But evolution cannot advance beyond that point.
According to anthropologists, evolution developed primates, and the highest form of primates, prior to modern humanity, were anatomically modern humans. These primates were much like modern human persons in their bodies (though not exactly so). But they lacked the ability to do abstract reasoning. Again, this is a theory from the science of anthropology. However, from the point of view of faith, anatomically modern humans are not human persons; they do not have the human ability to reason, and this implies that they lack free will, which then implies that they lack an immortal soul. Anatomically modern humans are the highest form of life that evolution could produce. It could go no further. Evolution cannot produce an immortal soul, not even with the help of the Providence of God.
So my belief is that God next intervened, miraculously, to create Adam and Eve. God patterned their bodies after the highest form of life on earth, anatomically modern humans. Their bodies were not exactly like the anatomically modern humans, but very close. And He gave them an immortal soul, with the full ability to reason (not merely pre-rational thinking) and free will. They were created miraculously in the Garden of Eden, which is not a place on earth. It is a place that is discontinuous with this universe, just as Heaven, Purgatory, and Hell are discontinuous with this life.
When Adam and Eve sinned, they were exiled to earth. Having bodies patterned after the highest form of animal life on earth (the anatomically modern humans), they were well adapted to live on this earth. From Adam and Eve, there arose the entire human species, as it exists today. Every ethnicity and “race” within the human race is of Adam and Eve. Anthropologists call human persons today “behaviorally modern humans”, and they distinguish us from anatomically modern humans by the fact that we can exercise the ability to reason abstractly.
So anatomically modern humans were produced by evolution, but behaviorally modern humans were produced miraculously by God. Evolution was not sufficient to produce modern humanity, because we have the gifts of abstract reasoning, free will and an immortal soul, which evolution was not able to produce.
Another point in the theory of evolution that many Christians, including more than a few Catholics, reject is the idea that the earth, life on earth, and the human race (behaviorally modern humans) have been around for a very long time. They interpret the first 11 chapters of the Book of Genesis literally, and so they do not believe that the human race could have begun more than several thousand years ago. They interpret those passages of the Bible literally, and so they don’t believe that God could have created the universe just under 14 billion years ago, and the earth about 4.5 billion years ago.
But I believe that some passages in the Bible are figurative and other passages are literal. We should not assume that Genesis is speaking literally when it describes Creation taking place over 7 days (not six days, by the way: on the seventh day God completed His work of creation, and then He rested). We should not assume that the ages for persons living prior to Abraham are literal lengths of time, with each person living hundreds of years.
Even the teachings of Jesus contain some figurative language along with literal expressions. “Love your neighbor” contains the literal command to love (in the spiritual sense). But it also contains the figure “neighbor”, which means treating even strangers as if they were next-door neighbors. So the term “neighbor” is figurative, and the term “love” is literal.
Based on this insight, I propose that the first 11 chapters of Genesis are partly figurative and partly literal. Adam and Eve literally existed as two human persons, but other elements in their story are figures: a fruit tree, a talking serpent, etc. So we need not conclude that Adam and Eve lived only 5000 or so years ago, nor are we required by faith to reject the current scientific understanding of the age of the earth and the age of the universe.
Anthropologists place the start of behaviorally modern humans 70 to 50 thousand years ago. There is no basis in Faith for rejecting that theory. It may well be that Adam and Eve were expelled from the Garden of Eden at that point in history. And the Bible account of the generations since Adam and Eve may skip many generations, and may summarizes its description of various groups of human persons under the figure of individuals. The authors of Genesis did not have much information on that time period; they had limited information handed down by past generations, in the form of parables or, we could say, parabolized history. And parables are full of figures.
More on this approach to science and faith in my book: Noah’s Flood: Literal or Figurative?
Incidentally, the story of Noah’s flood is partly literal and partly figurative.