Where does intelligent life come from? Does intelligent animal life – that is,
human life – simply emerge or evolve from lower forms of life?
When we look at the world around us, we can observe a gradation among living things.
Plants absorb nutrients, spread out their leaves towards the sun; they grow and reproduce.
Animals are, in a sense, more alive than plants: they have powers of sensation
and movement. And not only those: It’s easy to see in dogs, for example, that they have a memory:
we can train them through repeated action and reinforcement. They have emotions, too. They even
seem to be quite perceptive of our emotions, which makes them wonderfully empathetic companions.
But we find something even higher among human animals: we are, specifically, rational animals,
homo sapiens. Where does this higher intelligence come from?
In a previous video, we talked about the emergence of life in general.
According to Aquinas, it would be possible for God to create the world in such a way that living
things might emerge from non-living things. To be clear, for Aquinas, it would not quite be
right to say that primordial life SPONTANEOUSLY emerged from lower things, as if lower things,
absolutely of themselves, could give rise to higher forms.
Life has its ultimate origin in a higher cause – in God, the first cause of all. Still, it is
consistent with Aquinas’s thought to theorize that God might have sown this hidden form of life
in his creation from the beginning, like a seed that takes a very long time to germinate. Perhaps
the entire cosmos is a complex causal matrix that, considered as a whole, received this seed from God
in the beginning. Then, at the right time and through his providential governance of the world,
that hidden potency could become actual, through the complex interaction of secondary causes.
On this account, single-celled organisms might emerge first, and then, after a long time,
they might give rise to more complex organisms, eventually developing into the vast diversity
we find in the plant and animal kingdoms. It could even be the case that this eventually
led to the emergence of hominid animals. In broad strokes, many contemporary scientists think our
biological history looks something like this. It is important to pause here, however, because
a hominid animal is not yet a rational animal, even if he is one of our biological ancestors.
What's the difference? Human beings are rational animals.
Our rationality makes us intelligent. We are able not only to perceive, or to respond to stimuli,
or even to remember, but we are able to understand. Understanding something
means grasping more profoundly what it is. Classically, it means the ability to abstract
from matter: a dog may know this tree and that person, but only a mind endowed with a higher
intellectual power – the light of natural reason – can abstract from these particular things and come
to an understanding of what a tree and a person are in general, what is their essence or nature,
what makes them flourish, how to act in order to respect and honor their natures,
and so to behave justly towards them. Where does this intelligence come from? Unlike
plant or animal life, human acts of understanding and intelligence transcend matter – they belong to
the realm of the spirit, to what is immaterial. In fact, mere animals are not able to understand
the essence of a tree, a dog, or a human being. A dog does not reflect on what his life means,
and how he should live it. These kinds of things transcend what is possible for a mere animal.
St. Thomas Aquinas explains that a rational creature is endowed by God with a special light
of the mind, which he calls the light of natural reason. This is a power of the spiritual soul,
which is immaterial. A spiritual soul cannot simply arise from matter, from below,
because it has a share in God’s own light, which comes from above. The light of reason
is what allows man to transcend the limits of the material world and to begin to know and to love,
in the fullest and proper senses of those words. Knowing, understanding, willing, loving:
these are spiritual acts of a rational being, one that has an immaterial dimension.
It is true that our brains are material, bodily organs, and that our mental activity depends on
having a healthy body and a healthy brain. But our understanding cannot simply be explained by
or reduced to our brains, because understanding is more than a material process.
This is why the Catholic faith holds that, even if bodily and animal life emerged and
developed through a long process of evolution, God intervened in history and did something new
to bring about a new kind of creature, which we call the human being – a higher animal than had
ever before existed, endowed with a spiritual and therefore a rational soul.
We see this in the creation accounts in scripture. In earlier videos, we’ve
discussed how to read those biblical passages. They are not scientific or historical narratives,
but they all bear witness that God created man by a special act,
distinct from the creation of the rest of the animals, because man is unlike any other animal.
God said: "Let us make man in our image, after our likeness; and let them have dominion over the
fish of the sea, and over the birds of the air, and over the cattle, and over all the earth."
Genesis is revealing to us a fundamental theological truth about the creation of
the human being, even though it doesn’t tell us in scientific or historical terms precisely what that
special creation looked like. But we can be sure that it involved God directly infusing a new and
higher principle of life – an immaterial soul – as the form of a new and higher creature’s body.
By the way, it’s hard to be sure, but we might suppose that the first human being’s body
was also different from that of any previous animal, since the soul is the form of the body.
If we assume that the contemporary scientific accounts of biological evolution are correct,
we might hypothesize that, after a long period of evolution culminating in a non-rational hominid
animal, a new kind of being came into existence by God’s direct action of infusing a spiritual soul,
so that from a non-rational biological ancestor, something radically new came to be.
This would transcend what any process of evolution could itself bring about: the creation
of a rational animal, the first human being. In short, in order to have intelligent life, there
must be a spiritual soul endowed with the light of reason. Since it is an immaterial principle,
the human soul cannot simply emerge from below, from matter. It must be created directly by God.
In fact, it is the teaching of the Catholic Church that God does this at every human conception:
the father and mother contribute the biological foundation for a new human life,
but not the soul -- that is created directly by God at the moment of conception.
This also means that it is immortal: unlike a material animal soul,
a spiritual human soul does not cease to exist when the body dies – your soul will continue,
and it will be reunited with your body on the last day at the final resurrection.
It is wonderful to contemplate how God works in such varied ways in his creation – and to see how
the human being straddles the threshold between matter and spirit. Our biological life may trace
its ancestry back to the earliest organisms on earth, but we are not like any other animals:
God has given us a divine spark from above, and a destiny that points us
beyond the limits of this world, one that can only find its fulfillment in God himself.
For readings, podcasts, and more videos like this go to Aquinas101.com.
While you're there, be sure to sign up for one of our free video courses on Aquinas.
And don’t forget to like and share with your friends, because it matters what you think!