Thomism facts for kids

Thomas Aquinas (around 1225–1274)

Thomism is a way of thinking about philosophy and religion that comes from the ideas of Thomas Aquinas (1225–1274). He was a Dominican monk, a philosopher, and a very important religious teacher in the Catholic Church.

Aquinas's writings on Aristotle are some of his most famous philosophical works. In religion, his book Summa Theologica is one of the most important books from the Middle Ages. It is still a main guide for Catholic philosophy and theology today.

What is Thomism?

Thomas Aquinas believed that you should accept truth no matter where you find it. His ideas came from many different thinkers. These included Greek, Roman, Islamic, and Jewish philosophers.

Aquinas was a realist. This means he believed we can truly know the world as it is, unlike skeptics who doubt this. He often agreed with Aristotle and used Aristotle's ideas and terms. He even called Aristotle "the Philosopher."

He also used some ideas from neoplatonism. For example, he believed that God is the first and most perfect being and goodness. Everything else is good and exists because it "shares" in God's goodness.

Understanding Reality (Metaphysics)

Aquinas said that the basic rules for understanding reality are the principle of non-contradiction and the principle of causality. This means that anything that doesn't break these two rules could possibly exist. This includes things we can't touch or see.

How We Describe Things

Aquinas looked at three ways we use words to describe things:

Univocal words are used in the exact same way for different things. For example, "milk" means the same thing whether it comes from a cow or another mammal.
Analogical words change some of their meaning but not all. For instance, "healthy" can describe a person who is well. It can also describe food that helps you stay well. The meaning is related but not exactly the same.
Equivocal words change their meaning completely. For example, "bank" can mean the side of a river or a place where you keep money. This can cause confusion.

Aquinas also defined a "definition" as what a thing is, plus what makes it different from other things like it. For example, the definition of "man" is a "rational animal." "Animal" is what it is, and "rational" is what makes it different from other animals.

What It Means to "Be"

In Thomist philosophy, a "being" is "that which is." This has two parts:

"That which" refers to its quiddity (whatness). This is a thing's essence, form, or nature. It's what makes something what it is.
"Is" refers to its esse (Latin for "to be"). This means its actual existence or reality.

So, a being is "an essence that exists."

Beings are divided in two ways:

Things that exist by themselves are called substances. For example, a tree or a person.
Things that exist in another are called accidents. These are qualities like shape or color. They can only exist if there's a substance for them to be part of. Because substances are the main way things exist, Aquinas believed that studying substances is key to understanding reality.

The quiddity or form of a thing is what makes it what it is. It's like the blueprint that gives matter its specific characteristics. For example, an animal's body is its matter, and its soul is its form. Together, these make up its essence.

All real things have certain basic properties. These include oneness, truth, and goodness. Goodness means that all things have a final cause or a purpose.

Understanding Causes

Aquinas talked about four types of causes:

Material cause: What a thing is made of (if it has matter).
Formal cause: What a thing's essence or form is.
Efficient cause: What brings a thing into being or changes it.
Final cause: What a thing's purpose is.

Unlike some ancient Greeks, Aquinas argued that there cannot be an endless chain of causes. He believed that for anything to exist, there must be a first cause that started everything. Both Aristotle and Aquinas concluded that there must be an "unmoved mover" or a First Cause.

However, this First Cause doesn't have to be the very first thing in time. Aquinas believed that whether the universe had a beginning in time or was eternal was a matter of faith, not something that could be proven by reason alone.

What is Goodness?

Following Aristotle, Aquinas defined "the good" as what all things aim for. For example, a knife is good if it cuts well. Since everything has a purpose, all real things are good.

Because of this, evil is not a "thing" itself. Instead, evil is the privatio boni, which means a "lack of good." For example, blindness is a lack of sight, which is a good thing for humans to have.

Aquinas explained that people desire evil only because they think it will bring them some good. Their main goal is always good, even if they end up doing something bad by mistake.

Since God is the ultimate purpose of all things, God is goodness itself. Also, true love, in Thomism, means wanting what is good for another person and helping them get closer to God.

Does God Exist?

Thomas Aquinas believed that we can use reason to show that God exists. The Catholic Church teaches this view. In his Summa Theologica, Aquinas presented five ways to show God's existence. These are often called the quinque viae (Latin for "five ways"):

The argument from motion (things are moved, so there must be a first mover).
The argument from efficient cause (things are caused, so there must be a first cause).
The argument from possibility and necessity (things can exist or not exist, so there must be a necessary being).
The argument from degrees of perfection (things are more or less good, so there must be a most perfect being).
The argument from design (the universe shows order, so there must be an intelligent designer).

Aquinas also addressed the problem of evil. He said that God allows evil to exist so that greater good can come from it. For example, goodness chosen freely is better than goodness forced upon someone. But God Himself does not cause evil.

How Aquinas Saw God

Aquinas described God as the Christian faith understands Him. God is the only being whose existence is the same as His essence. This means God is existence itself. That's why God calls Himself "I Am that I Am" in the Bible.

Because God is existence itself, He cannot have a physical body. He cannot have "accidents" (qualities that change). He must be simple, meaning He is not made of parts. God is also goodness itself, perfect, infinite, omnipotent (all-powerful), omniscient (all-knowing), and eternal. Aquinas used the term actus purus (Latin for "pure actuality") to sum up these qualities.

Aquinas believed that God not only knows everything but that God is His understanding. God is the ultimate cause of the universe. He is the "first Cause of all things," the source of all being. God's actions are not like human actions. He causes and supports everything that exists at every moment.

Aquinas also taught that because God is infinite, humans can only speak of God using comparisons or "analogies." Some parts of God's nature are hidden, and others are revealed to our limited human minds. We can learn about God through His creation, but only in a way that compares to human understanding. For example, when we say God is "good," it's similar to human goodness but not exactly the same. The Bible also uses figurative language to help us understand spiritual truths through things we can sense.

Understanding Humans (Anthropology)

Summa Theologiæ, Part Two, First Part. (copy by Peter Schöffer, 1471)

Aquinas agreed with Aristotle that humans are "rational animals." He also had other beliefs about what makes up a human. He thought that all humans have the same essence or nature. So, real humans only differ by their specific qualities. Generally, all beings of the same type have the same essence. If they exist, they only differ by their accidents (changing qualities) and substantial form (what makes them that specific thing).

The Soul

Thomists believe the soul is the main form of living beings. Plants have "vegetative souls" (for growth). Animals have "sensitive souls" (for senses and movement). Humans alone have "intellectual" or rational souls, which are also immortal.

Human desires have two parts:

The rational part is called the will.
The irrational part is called passion (emotions).

How to Live Well (Ethics)

Aquinas agreed with Aristotle that happiness is "doing things according to perfect virtue." He said that happiness is man's highest good because it means reaching or enjoying that highest good. Aquinas defined virtue as a good habit. It's a good quality a person shows through their actions and reactions over time.

Aquinas identified four main virtues, called the cardinal virtues:

Prudence (wisdom)
Temperance (self-control)
Justice (fairness)
Fortitude (courage)

These virtues are natural and apply to everyone.

There are also three theological virtues:

Faith (belief in God)
Hope (trust in God)
Charity (love, especially for God and others)

These virtues are supernatural and focus directly on God.

Aquinas believed that humans cannot do good things without God's grace. This means that true happiness is achieved through God's grace and living a virtuous life. This happiness is not fully reached on Earth but only in heaven. Humans cannot find true happiness without God.

Regarding emotions (also called "passions"), Aquinas defined them as movements of our desires when we think about good or evil. He disagreed with those who thought happiness was just pleasure. He also disagreed with those who thought emotions were always bad. Aquinas took a balanced view, saying emotions are good if our love is good, and bad if our love is bad. Most emotions are neutral, but some are good (like pity) and some are bad (like envy).

Thomist ethics says that to decide if an action is morally good, you need to look at both the circumstances and the intention behind it. Aquinas believed an action is morally good if it fulfills God's will.

A notable idea is the principle of double effect. This idea helps explain when it's okay to do something that has both good and bad results. For example, it can justify homicide in self-defense. This principle was important for developing the idea of a Just War.

Understanding Law

Aquinas recognized four types of law. He defined law as "a rule of reason for the common good, made by the one who cares for the community, and made known to everyone."

Eternal law: This is God's wisdom guiding all actions and movements in the universe.
Natural law: This is how humans share in the eternal law. It's the light of reason God put in us, helping us know right from wrong. For example, everyone knows they shouldn't do to others what they wouldn't want done to themselves.
Human or temporal law: These are laws made by people because they are needed in society.
Divine law: These are moral rules given directly by God through revelation, like the Ten Commandments.

The idea of natural law is a very important part of Thomist philosophy. Aquinas said that natural law is "nothing other than the light of the intellect planted in us by God."

Aquinas believed that the Mosaic covenant (Old Testament laws) was divine. But he said it was only for the Jewish people before Jesus. The New Covenant (New Testament teachings) then replaced the Old Covenant and is meant for all humans.

Free Will

Aquinas believed that God gives humans "grace" (divine help) to do good things. This grace helps us choose good actions. The exact way this grace works with our free will has been a big discussion among thinkers.

How We Know Things (Epistemology)

Aquinas's ideas about knowledge are part of what's called the correspondence theory of truth. This means something is true when it matches what is real in the world. So, anything that exists is true because it is part of the world.

Aristotle's book De anima (On the Soul) says the mind has three parts for knowing:

Sensation: What we get from our five senses.
Imagination: When we remember something we sensed before, we form a mental image (a "phantasm").
Intellection: When we understand ideas or concepts from these mental images.

So, all human knowledge about general ideas (like what a "tree" is, not just one specific tree) comes from these mental images. Aquinas said, "the soul understands nothing without a phantasm." This means our knowledge starts with what we experience through our senses. If we make mistakes, it's often because we draw wrong conclusions from our sensations.

Aquinas's ideas about knowledge are often called empiricism. This is because he believed that sensations are a necessary step in getting knowledge. He also thought that we can't just figure out everything using pure reason alone.

Impact of Thomism

Aquinas changed Scholasticism (a way of thinking in medieval universities) from focusing on neoplatonism to focusing on Aristotle. His ideas became very important in Catholicism and influenced many people's lives.

Triumph of St Thomas Aquinas, Benozzo Gozzoli, 1471. Louvre, Paris

After Aquinas died, some of his ideas were challenged. In 1277, the Bishop of Paris even banned some of his teachings at the University of Paris. However, the Dominican Order, to which Aquinas belonged, defended his work. They later made his philosophy the official philosophy of their order.

Aquinas was made a saint in 1323. This helped to undo the bans on his ideas. Later, new thinkers like William of Ockham challenged Thomism.

Thomism remained strong, especially among Dominican thinkers. In the 16th century, it became very important in Spain and Portugal.

In the late 1800s, Pope Leo XIII tried to bring back Thomism, especially with his letter Aeterni Patris in 1879. This led to a movement called Neothomism. This movement focused on the ethical parts of Thomism and its views on life, humans, and religion. Neothomism was the main philosophy of the Catholic Church until the Second Vatican Council in the 1960s.

Thomism is still a school of philosophy today and is important in Catholicism. However, the Church does not say that any one philosophy is the only correct one.

Recently, some scientists have found connections between Thomism and modern brain science. For example, neuroscientist Walter Freeman suggested that Thomism's ideas about how we think match well with how the brain works.

Thomism and Jewish Thought

Aquinas was not afraid to use ideas from Jewish thinkers. His main work, the Summa Theologica, shows he knew a lot about Jewish philosophical writings.

Aquinas strongly disagreed with the idea that the world has always existed. He believed the world had a beginning, which agreed with both Christian and Jewish theology. He even argued that Aristotle himself wasn't completely sure about the world being eternal. Aquinas used ideas from Maimonides' Guide for the Perplexed to support his points.

How Thomism Changed Over Time

Thomism became less popular in the modern period, especially after René Descartes's works in the 1600s. Descartes's ideas about the mind and body, and his doubts about our senses, went against what Aristotle and Aquinas taught.

The history of Thomism shows how it has continued through the centuries. Some scholars divide Thomism into different periods. For example, the first period was from Aquinas's time (1200s) to his canonization in 1325. During this time, his ideas were both attacked and defended.

After Aquinas became a saint, more people wrote commentaries on his works. Later, in the 18th century, thinkers like Salvatore Roselli helped lay the groundwork for Neothomism.

The Thomist revival, or "neo-scholasticism," started in the mid-1800s. It was strongly supported by Pope Leo XIII's letter Aeterni Patris in 1879. This movement aimed to use Thomistic philosophy to analyze and critique modern ideas. Many Catholic colleges and seminaries used this approach before Vatican II (1962-1965).

24 Thomistic Theses

In 1914, Pope Pius X approved 24 statements called the "24 Thomistic Theses." These statements were meant to clearly show the main ideas and principles of Aquinas's philosophy.

Understanding Being (Ontology)

Everything that exists is either "pure act" (like God) or a mix of "potency" (what it can become) and "act" (what it is).
"Act" means perfection. It's only limited by "potency." So, if something is pure act, it's unique and unlimited. If it's limited, it's a mix of act and potency.
God is the only being that is pure act and absolutely exists. All other things that exist have a limited nature. They are made of an essence (what they are) and being (their existence), which are truly separate.
Things are called "beings" because they exist. God and created things are not called "beings" in the exact same way. They are called "beings" by analogy, meaning there's a similarity but also a difference.
In every created thing, there's a real mix of the main subject and other added qualities (like color or shape). These qualities are called "accidents."
Besides these absolute accidents, there are also "relations" (like being "taller than"). Even though a relation doesn't stick to something, it often has a real cause and is separate from the thing itself.
A spiritual creature (like an angel) is simple in its essence. But it still has two parts: its essence and its existence, and its substance and its accidents.
A physical creature is made of "act" and "potency" in its very essence. These are called "form" and "matter."

Understanding the Universe (Cosmology)

Neither matter nor form can exist by themselves. They are not created or destroyed by themselves.
Even though a body has parts that extend in space, being a substance is not the same as being extended. A substance is indivisible, not like a point, but as something outside of dimensions. Quantity (extension) is a real quality separate from the substance.
What makes one individual different from another of the same kind is its matter with quantity. So, in pure spirits, there can only be one individual of each kind.
Because of its quantity, a body is in a place and can only be in one place at a time, no matter how powerful it is.
Bodies are either living or non-living. Living things have a "soul" as their substantial form. This soul needs an organized body (with different parts) to move and be moved.

Understanding the Mind (Psychology)

Plant and animal souls cannot exist by themselves. They are just principles that make living things exist and live. Since they depend entirely on matter, they are destroyed when the living thing dies.
The human soul, however, exists by itself. It is created by God when it is put into a body that is ready for it. By its nature, it cannot be destroyed and is immortal.
This rational human soul is united with the body and is the only substantial form of the body. Because of his soul, a human is a human, an animal, a living thing, a body, a substance, and a being. The soul gives a human every essential level of perfection and gives the body a share in its existence.
From the human soul come powers that are either organic (like the senses, which need the body) or non-organic (like the intellect, which only needs the soul). The intellect is a power that doesn't depend on any bodily organ.
Being immaterial (not physical) means having intellect. The further something is from matter, the higher its intellect. The human intellect's main job is to understand quantities taken from the physical world.
We get knowledge from things we sense. But since sensible things are not directly understandable, our soul has an active power. This power takes understandable ideas from the images we form in our imagination.
Through these understandable ideas, we directly know universals (general ideas like "humanity"). We know individual things through our senses and also through our intellect when it looks at sense images. We learn about spiritual things by using comparisons.
The will (our power to choose) follows the intellect. The will always desires what is presented to it as good. But it can freely choose among many good things based on a changing judgment. The will is what makes the final choice.

Understanding God

We don't see God directly, and we can't prove His existence just by thinking about it. But we can prove it by looking at the things He created. We can reason from effects to their cause:
1. From things that move to a first unmoved mover.
2. From things that are caused to a first uncaused cause.
3. From things that can exist or not exist to a necessary being.
4. From things that have different levels of being, life, and understanding to something that is maximally understanding, living, and being.
5. From the order of all things to an intelligent being that ordered and directs them.
God's nature is pure existence itself. This is why He is infinitely perfect and unlimited.
Because God's being is pure, He is different from all limited beings. This means:
1. The world could only have come from God by creation.
2. No created being can have the power to create.
3. No created thing can affect anything else unless it has been moved by God, the first Cause.

Criticisms of Thomism

Some people have criticized Thomism. For example, Martin Luther thought that the way Thomists argued was sometimes too focused on style rather than strong evidence. He felt it led to shallow discussions in theology.

Bertrand Russell also criticized Thomism in his book A History of Western Philosophy. Some Catholics have also criticized the broader movement of neo-scholasticism, which includes Thomism.