Tradition holds that the medieval saint Thomas Aquinas levitated and had visions of our Lord. He was greatly concerned with explaining the mind of God, and he continues to matter because he helps us with a problem which still confounds us today; how we can reconcile religion with science and faith with reason.
Aquinas’ monumental contribution was to teach Western civilization that any person could have access to great truths whenever they made use of God's greatest gift to human beings, reason. Aquinas broke a log jam in Christian thinking over the question of how non-Christians could have both wisdom and at the same time no interest in or even knowledge of Jesus. Aquinas universalized intelligence. He opened the Christian mind to the insights of all of humanity from across the ages and the continents. The modern world insofar as it insists that good ideas can come from any quarter regardless of creed or background remains hugely in Aquinas’ debt.
As a young seminarian, Aquinas went to study at the University of Naples and there came into contact with a source of knowledge which had just been rediscovered, ancient Greek and Roman texts. Aquinas became an academic at the University of Paris where he was an exceptionally prolific writer, producing nearly 200 pieces about Christian theology in less than three decades. Aquinas brilliantly proposed that the universe and all its dynamics operate according to two kinds of law, secular natural law, and religious eternal law.
For Aquinas, a lot of the world follows natural laws. We can find out for ourselves how to smelt iron, build an aqueduct or organize an economy, and none of this relies on believing in God. Aquinas discussed Jesus's injunction to do unto others as you would have them do unto you. Jesus may have given this idea a particularly memorable formulation, conceded Aquinas, but it's in fact been a cornerstone of moral principles in most societies at most times. How could this be possible? Well the reason Aquinas argued, is that it's an idea that belongs to natural and not eternal law. Aquinas conceded that in a few situations, God does work simply through eternal law outside of human reason and he cited prophetic revelations and the visits of angels as examples. However, he reassured us that most knowledge can be found by anyone within the realm of natural law.
Aquinas’s ideas unfolded at a time when Islamic culture was going through a very similar dilemma as Christianity in terms of how one can reconcile reason and faith. For a long time, the Islamic caliphates in Spain, Morocco and Egypt had flourished by being open to knowledge from all over the world, generating a wealth of new scientific ideas and philosophy. However, due to the increasing influence of fanatical religious leaders, Islam had become more dogmatic and oppressive, by the time Aquinas was born. It had for example, reacted violently against the Muslim philosopher Averroes.
Like Aquinas, Averroes had been deeply influenced by Aristotle, and had argued that reason and religion could be compatible. However, the caliphates anxious never to depart from the literal words of God made sure that Averroes’ ideas would be banned and his books burnt. Aquinas knew that the Muslim world's increasingly radical rejection of reason was harming what had once being its thriving intellectual culture, and it was overwhelmingly thanks to Aquinas’s ideas that Christianity did not suffer the same process of stratification.
Though Aquinas was a man of deep faith, he provided a philosophical framework for open scientific inquiry. He reminds us that knowledge can and should come from multiple sources; from intuition, but also from rationality, from science, but also from revelation, from pagans, but also from monks. That sounds obvious until we notice just how often civilization has been, and is still being harmed, by people’s refusal to accept Aquinas’ profound insight.