How did God create Homo sapiens through evolution?
In the previous essay in this series on evolution and Christian faith, I explained that an account of biological evolution can be reconciled with a robust understanding of God’s providence, because God acts as a transcendent cause who can work in and through the natures of His creatures. In this essay, I would like to extend my remarks to the evolution of Homo sapiens. How did God set the stage for our species through evolution?
At this point, it is important to recall that human beings are spirit-matter composites. Each of us has a rational soul that informs a human body.
What exactly is a soul? Soul is how we explain life. When someone asks me why an apple falls to the ground, I tell him about gravity. Gravity explains why things fall. In the same way, when someone asks me why a cat is alive while a book is not, I tell him about the soul.
Soul explains why things are alive. A cat has a soul while a book does not. Note that if soul is the explanation of life, then every living corporeal thing has soul: A living rose is informed by a rose soul; a living kangaroo is informed by a kangaroo soul; and a living human being is informed by a human soul.
Reflecting on the capacities of the human soul, Aristotle and St. Thomas Aquinas concluded that our soul, unlike the rose soul or the kangaroo soul, is immaterial. But whereas rose and kangaroo souls are coextensive with matter, the human soul has to exceed matter because it is able to do things that exceed the capacities of matter. Specifically, Aristotle and Aquinas argued that the human soul is immaterial because it is able to grasp and process abstract ideas like “truth” or “justice” or “beauty” that do not have length, width, or height. To put it another way, the human soul is immaterial because it has the capacity to grasp the complex and abstract ideas, precisely the ideas that we find uniquely expressed in human language.
One of the things that Aristotle and St. Thomas Aquinas explained is that a soul is “fitted” to its body in the same way that a key is fitted to its lock. Thus, a human soul can only inform a body that is able to support those capacities. Biologically, this means that a human soul can only inform a body that has a brain that is complex enough to deal with and process language.
From a theological perspective, therefore, biological evolution was a 3.5 billion year process, directed by God, to advance living matter until it was apt to be informed by a human soul. As we will see in a later essay, this critical point in evolutionary history occurred 100,000 years in southern Africa among a group of anatomically modern human beings when a handful of individuals evolved the neurocognitive capacity for language.
As I explained in the previous essay in this series on evolution and Christian faith, evolution can be reconciled with a robust understanding of divine providence. The International Theological Commission of the Catholic Church, then chaired by Joseph Cardinal Ratzinger, put it this way:[A]ccording to the Catholic understanding of divine causality, true contingency in the created order is not incompatible with a purposeful divine providence. Divine causality and created causality radically differ in kind and not only in degree. Thus, even the outcome of a truly contingent natural process can nonetheless fall within God’s providential plan for creation. According to St. Thomas Aquinas: “The effect of divine providence is not only that things should happen somehow, but that they should happen either by necessity or by contingency. Therefore, whatsoever divine providence ordains to happen infallibly and of necessity happens infallibly and of necessity; and that happens from contingency, which the divine providence conceives to happen from contingency” (Summa theologiae, I, 22,4 ad 1).1
This is why it is intelligible for the Catholic theologian to claim that God guided the contingent process of evolution to advance living matter until it could be informed by a human soul. God guided biological history in the same way that he guides human history. He does so without undermining the contingent nature of history.
Importantly, only matter can evolve. Because it is immaterial, the human soul has to be created immediately by God. It cannot evolve.
Finally, given my reliance on St. Thomas Aquinas, some may claim that he would be opposed to this account of human evolution that holds that matter evolved, because he thought that God created all the kinds of living things at the beginning of time. This is not accurate. It is clear that St. Thomas acknowledged that the matter for at least one human being, in this case, Eve, existed before she was created by God:
Nothing entirely new was afterwards made by God, but all things subsequently made had in a sense been made before in the work of the six days. Some things, indeed, had a previous experience materially, as the rib from the side of Adam out of which God formed Eve (Summa theologiae I, 73.1 ad 3).
In the same text, St. Thomas continues by acknowledging that other species like the mule existed beforehand in their matter as well as in their causes:
Some things, indeed, had a previous experience materially, as the rib from the side of Adam out of which God formed Eve; whilst others existed not only in matter but also in their causes, as those individual creatures that are now generated existed in the first of their kind. Species, also, that are new, if any such appear, existed beforehand in various active powers; […] Again, animals of new kinds arise occasionally from the connection of individuals belonging to different species, as the mule is the offspring of an ass and a mare; but even these existed previously in their causes, in the works of the six days. Some also existed beforehand by way of similitude, as the souls now created (Summa theologiae I, 73.1 ad 3).
What is important is that the creation of each one of these new species has to be referred back ultimately to God’s creative activity. God, who alone creates, worked through evolution in preparing the matter of the bodies of the first humans.
— Rev. Nicanor Pier Giorgio Austriaco, O.P.
International Theological Commission, “Communion and Stewardship: Human Persons Created in the Image of God,” no. 69. Available at http://www.vatican.va/roman_curia/congregations/cfaith/cti_documents/rc_con_cfaith_doc_20040723_communion-stewardship_en.html. ↩