The Most Significant Date in the History of Western Civilization

December 6, 1273.

That's the date St. Thomas Aquinas had such an intense experience or vision during Mass, that he stopped writing.

For 35 years, Aquinas had used the written word to explain pretty much everything. He provided proofs of God's existence that atheists still struggle to refute. He wrote legal treatises, showing how the divine law works through the natural law to give us human law. He described the virtues; he described the vices. He explained the sacraments.

And then he stopped in the middle of Part III of his Summa Theologica and told his friend that everything he had written seemed like chaff.

Some historians speculate he'd had a stroke, but that's highly unlikely. He wasn't aphasic: his intellect and speech were perfectly normal until he died a few months later.

Perhaps I should restate that. His intellectual and speaking abilities were perfectly intact.

His refusal to use them after his experience at Mass hardly seems normal to us today.

The Clash within Aquinas Was a Showdown between the Hemispheres

Aquinas didn't have a stroke. He had a mystical experience.

Iain McGilchrist calls the event "the single most dramatic demonstration of the inadequacy of prose to speak of the divine."

He's right, but I'd take it further: The event was the greatest showdown between the left and right hemispheres ever seen.

Aquinas was a man of massive rational (left hemispheric) abilities and Aquinas was a massively holy man (a right-hemispheric quality . . . only the right hemisphere communicates with the divine). They clashed with one another on the Feast of St. Nicholas in 1273, during Mass.

Aquinas' left hemisphere's explicit intellectual efforts and the avalanche of written works that came out of it crashed into his right hemisphere, but his right hemisphere didn't flinch.

His explicit thought processes and the words that flowed from them dissipated.

Like chaff in the wind.

Aquinas himself was fine, but the efforts of his left hemisphere--written words--were demolished. He saw--intensely, up close, first-hand--that words could never convey what he had seen.

So he quit.

The right hemisphere's dominance in the clash was total.

Aquinas Was and Continues to be Relevant

So why do I claim the event is the most significant event in the history of Western Civilization?

A lot of reasons.

There is the showdown itself. A champion of the left hemisphere clashes with a champion of the right hemisphere, and the right hemisphere wins.

Aquinas was the pinnacle of Western Civilization: he embodied the proper relationship of the hemispheres. Aquinas' mystical experience provides an obvious apex for the timeline of our intellectual landscape: on the trip up to the apex, we have the Middle Ages; on the trip down, we have Modernity.

After Aquinas, the left hemisphere– slowly at first, then with increasing rapidity--started to take control of Western Civilization. The story is told in this series of essays and will form a large part of the story told in these Catholic Hemisphere pieces.

Perhaps most importantly, Aquinas is a saint. His life itself teaches about how the left hemisphere can be fully engaged without going rogue. His life, in other words, shows us how to live vigorously with our left hemisphere but under the sweet yoke and light burden of the right hemisphere.

Aquinas, in other words, was relevant to the thirteenth century. He was just as relevant 300 years later when his Summa was placed with the Bible on the altar during the Council of Trent. He was relevant 700 years later as post-modernist-type philosophers came to see the limits of rationalization and turned to pre-modernist ways of seeing.

And he's relevant now, 800 years later, as neuroscience begins to appreciate what Aquinas experienced.