The Great Philosophers: Thomas Aquinas

It seems, at first, weird that we might learn from him. Thomas Aquinas was a medieval saint, said in moments of high excitement to levitate and have visions of the Virgin Mary. He was much concerned with explaining how angels speak and move. And yet…


Thomas Aquinas, comforted by angels 

He continues to matter because he helps us with a problem which continues to bedevil us: how we can reconcile religion with science and faith with reason. Aquinas was both a philosopher and a holy saint. Refusing either to lose his faith or mindlessly believe, he developed a new understanding of the place of reason in human life. Aquinas’s monumental contribution was to teach Western European civilisation that any human being – not just a Christian – could have access to great truths whenever they made use of God’s greatest gift to human beings: reason. He broke a logjam in Christian thinking, the question of how non-Christians could have both wisdom and at the same time no interest in, or even knowledge of, Jesus. He universalised intelligence and opened the Christian mind to the insights of all of humanity from across the ages and continents. The modern world, in so far as it insists that good ideas can come from any quarter regardless of creed or background, remains hugely in his debt.

Thomas Aquinas was born to a noble family in Italy in 1225. As a young man, he went to study at the University of Naples and there came into contact with a source of knowledge which was just then being rediscovered: that of the Ancient Greek and Roman authors, who had previously been shunned by Christian academics. At university, Aquinas also came under the influence of the Dominicans, a new order of monks who, unlike other groups, believed that they should live in the outside world, rather than a cloister.


Against the will of his family Aquinas decided to join the order. His family’s questionably pious response was to kidnap him and lock him in a tower they owned. Aquinas wrote desperate letters to the Pope, arguing his cause and pleading to be set free. However, the pope was busy with political matters, and so Aquinas stayed locked up, and passed the time writing letters to Dominican monks and tutoring his sisters. According to one legend, during this time Aquinas’ family even furnished him with a prostitute in a low-cut top in the hopes of seducing him away from his idea of being a monk, but Aquinas drove the young lady away with an iron bar.

Seeing they were getting nowhere, finally, his family unlocked the door and the (in their eyes) wayward Aquinas joined the Dominican order for good. Resuming his interrupted education, Aquinas went to study at the University of Paris, where he was a remarkably quiet student, but an exceptionally prolific author, writing nearly two hundred pieces about Christian theology in less than three decades. His books bear beautiful and strange titles the ‘Summa Theologica’ and ‘Summa contra Gentiles’. He also became a hugely popular and influential teacher, and was eventually allowed by the Dominican leadership to found his own school in Naples. Such was his devotion to knowledge, even at the moment of his death (at the age of forty-nine), he is reputed to have been in the middle of delivering an extended commentary on the Song of Songs. After he died, he was canonised in the Catholic Church and is now the patron saint of teachers.


One of Aquinas’s central intellectual ambitions was to understand how people could know what was right and wrong – a far from academic concern because, as a Christian, he wanted to know how a person could be sure that their actions would allow them to go to heaven. Aquinas was aware that many ideas which seemed extremely right were not the work of Christians. For example, he especially admired Aristotle: a man utterly unacquainted with the truths of the Gospels. It was in response to this dilemma that Aquinas made a highly important argument for the compatibility of religious belief and rational thought 

Many great philosophers were pagans, Aquinas knew, but this did not bar them from insight because, as he now proposed, the world could usefully be explored through reason alone. To explain how this could work, Aquinas proposed that the universe and all its dynamics operated according to two kinds of law: ‘natural law’ and divine ‘eternal law’.

The key point for Aquinas is that natural law is a subsection of eternal law, and it can be discovered through the faculty of independent reason. Aquinas gave as an example 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, but it has in fact been a cornerstone of moral principles in most societies at all times. How is this possible? The reason, Aquinas argued, is that natural law doesn’t need God’s direct intervention in order to make itself known to man. Just by reasoning carefully, one is intuitively following God’s intentions. Aquinas allowed that in a few situations God works simply through divine law, outside of the limits of human reason; and gave the example of prophetic revelations and the visits of angels. However, most useful knowledge could be found within the realm of natural law. 


Aquinas’s idea that anyone could deduce what is true also proved politically liberating, for it could be extended beyond the dichotomy of Christian and pagan, and encompass divisions between the powerful and the weak. He argued that slaves should generally obey their masters and children their parents, but not if they were ordered to do something that was against natural law. This was to provide a conceptual framework for theories of moral political dissent — a tradition that has continued into our own time in the form of protests, nonviolent resistance, and even outright revolution against tyrannical governments.

Aquinas’s ideas unfolded at a time when Islamic culture was going through very similar dilemmas as Christianity, in terms of how to reconcile reason and faith. For a long time, the Islamic caliphates in Spain, Morocco, and Egypt had flourished, generating a wealth of new scientific knowledge and philosophy. However, due to the increasing influence of rigid religious leaders, they had become more dogmatic and oppressive by the time Aquinas was born. They had, for example, reacted violently against the Islamic philosopher, Averroës (Arabic name Ibn Rushd). Like Aquinas, Averroës had been deeply influenced by Aristotle, and had argued that reason and religion were compatible. However, the caliphates – anxious never to depart from the literal words of God – had made sure Averroës’ ideas were banned and his books burned.


Aquinas read Averroës, and saw that he and the Muslim scholar were engaged on similar projects. He knew that the Muslim world’s increasingly radical rejection of reason was harming what had once been its thriving intellectual culture. It was partly thanks to Aquinas’ ideas that Christianity did not suffer the same process of stultification as Islam.

Nearly four hundred years later, for example, Galileo was to use Aquinas’ writings to justify his pursuit of scientific knowledge in ways that went beyond scripture. The spirit of free inquiry that we value in academic education today is also Aquinas’ legacy: he advocated for an early form of what we would now call multiculturalism.


Though Aquinas was a man of deep faith, he therefore provided a philosophical framework for the process of doubt and open scientific inquiry. On a more personal level, Aquinas reminds us that wisdom (that is, the ideas we need) can come from multiple sources. From intuition but also from rationality, from science but also from revelation, from pagans but also from monks: he’s sympathetic to all of these; he takes and uses whatever works, without caring where the ideas come from. That sounds obvious, until we notice just how often we don’t do this in our own lives: how often we get dismissive if an idea comes from an (apparently) ‘wrong’ source: someone with the wrong accent, a newspaper with a different political creed to ours, a prose style that seems too complicated, or too simple – or an old lady with a woolly hat.