Feast of St. Thomas Aquinas

Today is the feast day of the Angelic Doctor, the great Dominican theologian Thomas Aquinas (c. 1225-1274). The son of a noble family, Thomas began his monastic career as a Benedictine, left by his parents as a child to be raised and educated by the monks at Monte Cassino. Impressed by the zeal of the new mendicant orders, Thomas professed as a Dominican, over his parents' objections. As a theological hero of Dante, Aquinas makes an important appearance, speaking in the Sphere of the Sun section of Paradiso:

"And let this always be as lead upon your feet
to make you slow, just like a weary man, in moving,
whether to yes or no, unless you see both clearly.

"For he ranks low among the fools
who, without making clear distinctions,
affirms or denies in one case or another,

"since it often happens that a hasty opinion
inclines one to the erring side, and then
fondness for it fetters the working of the mind.

"He who casts off from shore to fish for truth
without the necessary skill does not return the same
as he sets out, but worse, and all in vain.

"Clear proof of this was given to the world
by Parmenides, Melissus, Bryson, and others,
who went to sea without a port in mind.

"Such were Sabellius and Arius and the fools
who misread Scripture as a sword reflecting
the distorted image of a face upon its blade.

"Let the people, then, not be too certain
in their judgments, like those that harvest in their minds
corn still in the field before it ripens."

-- Dante Alighieri, Paradiso, Canto 13: 112-132,
translated by Robert Hollander (with thanks to Princeton Dante Project)

In the fresco by Andrea da Firenze shown above, Thomas is seated with a book, and the heretics Sabellius, Averroes, and Arius lie prone at his feet. The concern expressed by Dante's Aquinas, that one must understand all of the arguments both for and against a hypothesis, pervades Aquinas's most famous work, Summa Theologica, in which all possible objections to each point are raised, defended, and ultimately undone. It is a breathtaking tour de force of scholastic argument.

Image: Detail of Andrea da Firenze's Triumph of Thomas Aquinas over Heresy, c. 1365, fresco in the Spanish Chapel, Santa Maria Novella, Florence

Related: The Cranky Professor venerated the armbone of Thomas Aquinas today, in the church of Santa Maria sopra Minerva in Rome. He did not mention Filippino Lippi's fresco cycle on the life of Aquinas in the Carafa Chapel there, but it was a close second choice for the image to accompany this post.