Saint Thomas Aquinas

“Faith Seeking Understanding” ~ Saint Anselm of Canterbury (1033-1109) 

St. Thomas Aquinas is considered the greatest Catholic philosopher and theologian. He’s renowned for his unique ability of demonstrating harmony between faith and reason, and between Christianity and philosophy. His five proofs of the existence of God have withstood the test of time and are still taught at any good Catholic seminary to this day.  It can be argued today that science is now pointing the way to God.  Albert Einstein’s theory of relativity, the Hubbell Telescope, DNA Molecules, and just last year the Higgs Boson particle, all seem to display some sort of intelligence working behind the scenes in the universe.

800 years ago Saint Thomas Aquinas argued this idea very effectively and as a result, his philosophy and theology have been taught in Catholic seminaries and schools since the 13th Century.  As a young man, Thomas was introduced to the works of the Greek philosopher Aristotle.  Much of his life was devoted to studying Aristotle’s teaching, exploring its logical principles and demonstrating its value for Christian thought.  The idea of the Unmoved Mover was introduced by Aristotle 1,600 years before the birth of Aquinas.  Thomas Aquinas supported Aristotle’s idea and demonstrated that the motion we have today is traceable to an initial motion originator, referred to by millions of people throughout countless civilizations as the Supreme God.  Aquinas was a Catholic Priest from the Dominican Order who taught theology throughout Europe. He was a prolific writer, and his greatest work, the Summa Theologiae, states his conviction of the natural harmony between faith and reason.


Aquinas sees reason and faith as two ways of knowing. “Reason” covers what we can know by experience and logic alone.  From reason, we can know that there is a God and that there is only one God; these truths about God are accessible to anyone by experience and logic alone, apart from any special revelation from God.

“Faith” covers what we can know by God’s special revelation to us, which comes through the Bible and Catholic Tradition. By faith, we can know that God came into the world through Jesus Christ and that God is triune (Father, Son, and Holy Spirit). These truths about God cannot be known by reason alone.

According to Aquinas, faith builds on reason. Since faith and reason are both ways of arriving at truth — and since all truths are harmonious with each other — faith is consistent with reason. If we understand faith and reason correctly, there will be no conflict between what faith tells us and what reason tells us.


Saint Thomas Aquinas five ways to know the existence of God:

  • PROOF I – From Motion
  • PROOF II – From Cause
  • PROOF III – From Necessary and Contingent Being
  • PROOF IV – From Levels of Perfection
  • PROOF V – From Order

Proof one from motion states that everything that we see in the universe is in motion.  Like a leave falling from a tree, a river, people etc.  And everything in the universe didn’t get itself in motion.  It was placed in motion by something or someone else.  Saint Thomas refers to this as the first mover.  There has to be a first mover who itself was not moved and yet is the cause of all motion.  Hence, the unmoved mover.  A train needs an engine to get into motion.  We had to have parents who got together to put us into motion.  But your parents aren’t the source of ultimate motion, because they had to be placed in motion.  In order for you to learn to talk and walk, you had to be placed in motion intellectually by someone who has actualized the knowledge and can communicate that to you.  The unmoved mover is not in motion physically he is not in motion intellectually.  Nothing, no one moved Him.  He is pure actuality, pure act.  The unmoved mover can’t walk from here to there, he’s already there.  If He could He wouldn’t be the unmoved mover.  He can’t come to learn something because he already knows it.  He is pure actuality.

Proof two from cause, states everything has a cause.  This is one of the foundational principles of the scientific method.  When we see anything in the universe we know it has a cause. Which means that if everything in the universe has a cause then that means nothing in the universe can explain itself.  Therefore there must be an uncaused cause.  Like the unmoved mover there must be an uncaused cause.  And what that tells us is the unmoved mover and uncaused cause has no beginning and therefore He must be eternal.


Proof three from necessary and contingent being.  Everything in the universe can either be or not be.  There must be a being who did not receive its being from anything else.  The reason you can either be or not be is because you received your being from someone else. Just like the Sun can either be or not be.  The Sun received its being from something else, something or someone created it.  We received our being from our parents.  So there must be a being that is pure being, having not received its being from something else.  Its essence is existence.  Here’s an interesting tidbit, in the Bible, in the chapter 3 of Exodus verse 14, God revealed himself to Moses in this way – I AM WHO I AM.  Meaning pure being, or eternal.

Proof four from levels of perfection states that when we look around the universe we see things in various states of perfection.  That being the case, there must then be a being that gives all perfection but did not receive its perfection.  Meaning the unmoved mover and the uncaused cause has all perfection.

Proof five from order states that when we look around in the universe we see things ordered to ends that they did not devise.  Meaning they had nothing to do with order itself.  We had nothing to do with our own creation any more than a flower, an animal, a planet, the sun etc.  There are purposes and orders designed within ourselves that we didn’t give ourselves.  Therefore, there must be an ultimate source of all purpose that did not receive its purpose from anyone else.


Of course, Saint Thomas’ proofs do not absolutely prove the existence of God because they can be argued. It is faith that provides the bedrock for belief in God.  Nevertheless, these five proofs can help show that Christianity is a rational religion.

Science tells us that the Universe began 13.7 billion years ago.  Physicists tell us that all the galaxies and stars in the Universe can be traced back to one singular point.  They call this singularity, or the big bang theory.  Some faith based people refer to singularity as creationism. Physicists have a hard time with the concept of singularity when they try to get back to the moment of creation, because they always end up running into infinity.

images (1)

Albert Einstein in his theory of relativity E=MC2, breaks now like this; Energy = Mass x the speed of light (2).  Meaning it took a whole lot of energy to create a little bit of mass.  Energy is another form of matter and matter is another form of energy.  And physicists agree that energy has a beginning point.  Energy is another form of matter and matter is another form of energy.   They are relative to each other.

Science today can look at a DNA molecule, a human cell and see that it has almost a million working parts inside it.  The human body has 3 trillion cells in it with almost one million cells inside each cell that operate like machines inside of machines that are so complex and precisely designed that Microsoft founder Bill Gates once remarked that, “One human cell makes my greatest super computer look like child’s play.


Last year physicists declared that they have uncovered the elusive Higgs Boson particle or the “God Particle”, which is a subatomic particle that holds all other particles together, sort of like a glue particle.  It is believed that everything in the universe at one point was all together, one mass.  But after the Big Bang things separated and took on different properties.  The particles that we are made up of – protons, neutrons, and electrons, have mass but no one is sure why.  Physicists now believe that there is an exchange of particles, infused particles, subatomic particles that give them mass which hold us and the universe all together – the God Particle.

So in conclusion we covered Aquinas’ five proofs of the existence of God, from Motion, from cause, from necessary and contingent being, from levels of perfection, and from order.  We covered the ways that science seems to be pointing to God from Einstein’s theory of relativity, through DNA molecules, and most recently the Higgs Boson Particle.  Therefore, faith seeks understanding and reason can point to faith.  Catholic theology states that faith is a gift that has to be cultivated through the reading scripture and the writings of the Doctors of the Church.  I would like to end with a quote from the late and now Blessed John Paul II, who said, “Faith and reason are like two wings on which the human spirit rises to the contemplation of truth; and God has placed in the human heart the desire to know the truth — in a word, to know himself — so that by knowing and loving God, men and women can come to the fullness of the truth about themselves”.

~ John Andrew Dorsey



Filed under Uncategorized

3 responses to “FAITH AND REASON

  1. Susan

    As someone who is trying to learn as much as possible about my faith, I really enjoyed this article – as was meant to do, it made me stop and think ..thank you

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s