Efficient Causes and the Existence of God: Aquinas' Five Ways

We are in the sensible world, an order of efficient causes.

However, nothing is the efficient cause of itself; it would be prior to itself, which is impossible. Efficient causes cannot proceed indefinitely.

1. Order in Efficient Causes: The first is due to the intermediate, and the intermediate, whether one or multiple, is the last. If you remove the cause, the effect disappears. If there were no first in the order of efficient causes, there would be no last or second.

2. Infinite Efficient Causes: If we take efficient causes to infinity, there would be no first efficient cause, and consequently, no ultimate effect or intermediate cause, which is false. Therefore, it is necessary to admit a first efficient cause: God.

Explanation

This is the argument from efficient causes. Motion is an act of the mobile, considering the world's beings as passive, potential actions caused by others. The second part is motor activity, the existence of efficient causes that are subordinate acts to produce an effect. The existence of an order or series of efficient causes is subordinate to experience. The first principle of this approach says that nothing is the efficient cause of itself. The proof is immediate: to cause, it needs to be; to be its own cause, it would be prior to itself, which is contradictory. Causality itself is either uncaused or caused by another. The second principle states that it is impossible to proceed to infinity in the number of efficient causes. The reason for this inability is that if the process goes to infinity, there would be no first cause and, therefore, no effect. In any order of subordinated causes, the first causes the second, and this the last. If there were no first, there would be no activity of the intermediate or last. The conclusion is the existence of a first efficient cause that meets the nominal definition of God. God appears under the formality of the first efficient cause, unlike any other subordinate in action.

Antecedents

• Plato's Timaeus: A perfect craftsman made the sensible world from a mass or space, modeled on the world of ideas.
• Saint Augustine: Established the existence of God based on causality. If we ask who made the world and all creation, we would answer God did.

The Four Ways Explained

1. First Way, the Moving World: There are things not moving; everything in motion has an engine; a process to infinity is impossible. The observation of motion leads to the admission of a first immobile mover, God. This is Aristotle's way.
2. Third Way, Contingency: Beings in the world are born and seem to be and not to be. Since what comes into existence does so through another that already exists and cannot proceed to infinity, contingent beings postulate a necessary being, God.
3. Fourth Way, Perfection: Beings in the world are more or less perfect, but always with respect to a maximum. There must exist a being that contains all perfections in the highest degree, the cause of partial perfections in sensitive beings, a supreme being, God.
4. Fifth Way, World Governance: Beings in the world, lacking knowledge, tend to fulfill their purpose. They do not tend to an end unless directed. There must be an intelligent cause directing the world to an end, God.

Evidence of God's Existence

Saint Thomas offers five routes:

1. A starting point: finding an effect in natural beings.
2. Applying the principle of causality: every effect has a cause.
3. Applying the principle of impossibility of an infinite process in the series of subordinated causes.
4. Completion: the existence of the first under the formal cause of an attribute that denies the formality of the starting point, corresponding to God.

Concepts

• Movement: Update of what is in power as such or the power to step into act. Aristotle distinguishes two senses of movement: broad (all change, substantial and accidental) and strict (only quantitative change).
• Power: A mode of being between nonbeing and being in act. It is potentially able to become.
• Act: Realization of what is on the way to being power. It is what has become after change.
• Motor: Moves. What is needed to act on that which moves.
• God: For Saint Thomas, being itself subsisting. Essence and existence are identified. Simple, perfect, infinite, and necessary.