Thomas Aquinas, Quantum Physics, and the Nature of Reality

I am a big fan of Thomas Aquinas, the 13th century Saint and philosopher. Aquinas is known for his arguments in favor of the existence of God and his seminal work Summa Theologica.

Aquinas strongly believed that faith and science should be united. He refutes the claims of modern scientists that God cannot exist because we cannot find evidence of him in the material world. He believed that God could be proved through logical deduction in the tradition of Aristotle, Plato, and Socrates.

Aquinas lived long before Kant and so didn’t have problems with reality or the nature of reason. He lived in a world that had rediscovered classical logic and philosophy and was trying to work it into its worldview. The primary problem he had was how to reconcile the “science” of Aristotle and the Greek philosophers with Christian thinking.

Aquinas’s Catholic church had, for centuries, been essentially neo-Platonist, meaning that its worldview was such that there was the corrupt Earth, a divine and perfect Heaven, and a place of eternal punishment that counterbalanced Heaven, Hell.

There was little room for logic or science in such a worldview. It was essentially a world of symbolism. Every real thing reflected God’s ideal and therefore existed to symbolize some heavenly reality.

Unlike our largely secular Western world, Aquinas inhabited a world where religion was dominant and science had to bow to it. Yet, it was also a world that was clearly hungry for a different way of thinking and Aristotle offered that way.

Aquinas’s worldview did not address any of the problems that later philosophers would wrestle with. It said little about questions of how we could know things. It took an implicitly realist stance and assumed we could know things as self-evident premises. It was mainly concerned with how the Aristotelian logic could serve the Christian worldview.

Nevertheless, Aquinas offered no quarter when it came to attacking Christian assumptions and beliefs. Unlike most other religions, Christianity has a long history of attacking itself and, by doing so, has developed a very robust theology. Sadly, most Christians are completely ignorant of it and Christian detractors assume Christianity has poor defenses.

Most of his arguments were presented like mathematical proofs where the opposite of what was desired to be proved is assumed and then a logical contradiction reached. This is a very popular way of proving theorems, called reductio ad absurdum.

While I write about a great many philosophers in my articles, I haven’t written much about Aquinas because he didn’t address the problems I tend to deal with like realism vs. anti-realism, the nature of consciousness, etc.

Still, having finished my recent article on quantum theory and the philosophy of Wittgenstein on medium.com, I got to thinking about what Aquinas might think about quantum theory and the nature of reality through the lens of modern physics.

After all, Aquinas was deeply interested in the science of his day, so why wouldn’t he be interested in the science of our day?

Aquinas’s main goal was always to use the best of science and philosophy in his day to support his belief in the Christian Gospel, particularly its most basic beliefs in an Eternal Creator God.

I think that today he would see modern science, quantum theory, evolutionary theory, the age of the universe, and so on and think of them as evidence of the hands of the God in which he believed. Indeed, Aquinas always supported the idea that God works through secondary causes.

Moreover, I don’t think Aquinas would be all that concerned about the problem of how things began. Beginnings seem to be of much greater concern to Atheists than theists (at least ones who know philosophy). Aquinas never saw God as the One who started the universe at some point in the distant past. He saw God as one who allowed the universe to exist at any and all points in history and the future.

I think Aquinas would see the four dimensional spacetime theory of Einstein as proof of the idea that God created the universe as a whole, including all of history from beginning to end, from Big Bang to Judgement Day. The story of Genesis, where God creates the world in the Bible, is, in some sense, a story about beginnings of Earth and man, but not necessarily about how God created everything.

I think he would see evolutionary theory as merely the mechanism God chose to create human beings and animals and I think he would appreciate its beauty.

On quantum physics, I believe he would have a lot to say because he wrote extensively on metaphysics and quantum philosophy is deeply concerned with answering the question: what is reality?

Aquinas’s concept of metaphysics is about two ideas: essence and existence. Thomas argued that these are distinct in that something can have essence, i.e., a definable nature but not exist. If a thing’s essence is its existence, however, there can be only one such thing. He goes through a detailed argument for this.

For Aquinas, the essence of a material thing is a composition of its matter and form. You can think of matter as being sort of primary, undesignated stuff while form is the shape it takes. A painting is made of paint globs and canvas. The picture it makes is its form. Both come to together to create the painting’s essence.

He argues that, when anything multiplies, it distinguishes itself and so gains a different essence or it must take on its creation as part of its existence but not its essence. Cells divide and become distinct from one another. Their existence depends on the existence of the original cell but their essence does not.

Aquinas isn’t talking about something like DNA which passes down the encoding for essence from cell to cell here. He is talking about the actual matter form of it which is clearly distinct from the causes that enabled the cell’s existence.

From this Aquinas argues that essence and existence must be different.

This is true even of subatomic particles which have as their essence their particleness, but their existence is predicated on their emerging from some collision or high energy interaction. The origin of a particle, even if at the Big Bang, is part of its existence but not essence.

Aquinas argues that there is one thing such that its existence and essence are the same and that is a thing that causes its own existence. There can only be one such being and that being must be what we call God.

Bertrand Russell held that there were physical things such that essence and existence were the same. He suggested conserved quantities like energy are an example. Unfortunately, most conservation laws can be broken under the right circumstances, even the conservation of energy. And it is not clear that the laws of physics are not caused by something.

Ultimately, Aquinas would argue that all physical things must receive their existence from a non-physical thing.

In the case of quantum field theory, you can think of the undisturbed field as being undesignated matter and the excitation of the field into a localized point of a particle as its having been given form. I think Aquinas would find this very satisfying as it is a very pure example of his ideas.

On wave particle duality, Aquinas might see a particle in a superposition of states, like going through a double slit apparatus, where it appears to only have a distinct state when observed as simply a matter of cause and effect. In that, the act of observation causes the particle to adopt a distinct state. This does not mean the particle’s state was not real before. Rather, it had a state that was not consistent with having been observed. The particle is still, however, a material object.

I could say a lot more about Aquinas. I certainly feel like we need more of his kind of thinking in today’s world.

Aquinas wasn’t interested in playing word games or philosophy as therapy. He was nothing if not practical which is probably why his philosophy has remained popular for over 700 years.