Thomistic Approaches for the Existence of God
"The judgment of any system or a priori relation exists in any rational, or metaphysical, or at least epistemological contradiction to an abstract and empirical concept such as being, or to be, or to occur, in the thing itself or of the thing itself." -- Diane Keaton to Woody Allen, Love and Death
Thomistic Approaches for the Existence of God
Can God's existence be demonstrated? Thomas' answer is yes. The reason being is that 'the existence of God and other like truths about God, which can be known by natural reason, are not articles of faith, but are preambles to the articles; for faith presupposes natural knowledge.'
Thomas' proofs are a posteriori, not a priori. This means that from the effect, we can conclude a cause. From the world or universe, we can establish some things that would conclude a Perfect, Unlimited, and Independent Being.
(1) The first thing we can establish is that there is motion in the universe. Motion is another word for change or from the state of potentiality to actuality. For example, our thoughts change. No one can deny change. But whatever is in motion is moved by another since nothing can move itself. To deny this is to say that a potentiality can actualize itself, a nonbeing into a being, meaning a greater can come from a less. That is absurd since nonbeing cannot produce being since nothing can't produce something.
Therefore motion can only be moved by another or a potentiality can only be actualized by an act. If every motion is moved by another, can there be an infinite number of movers? According to Thomas, an infinite series of movers accidentally subordinated to one another in time is possible. This is because God could have made an eternal universe. However, an eternal universe must have a reason for its existence just as an eternal footprint needs a foot.
However, motion exists now. Since it exists now, we must explain its existence. However, an infinite number of movers does not explain the series of motion. Only when I arrive at an Unmoved Mover am I to give a full explanation of motion. The Unmoved First Mover, therefore, is not the first in order of time, but in the order of rational sufficiency.
But some may ask, 'Who moved the First Mover?' The answer is simply that the Unmoved First Mover alone answers the true idea of a mover. A secondary mover, insofar as it is a secondary, is not a mover at all. For example, if I see a mover, but found that that this is moved by something else, what happened to the mover? It has become actually a motion. It makes no difference how often I go back to each mover, but until I arrive at a First Mover, the idea of motion will be unexplained.
Therefore in order to explain motion in the universe, there must be an Unmoved First Mover. Since changing beings consists of act and potency, and the First Mover is unchanged, then the First Mover must be Pure Act. There cannot be more than one Pure Act because they would coincide.
(2) Another fact we can establish is that we see things that are more or less good, more or less true. The universe is made up of beings that are composed of varying degrees. Since there are degrees of perfection in beings, this fact presupposes that a Perfect Being exists.
Following Fulton Sheen's footsteps, we have a desire for truth, life, and love. Yet in this world, truth is mingled with error (lack of truth), life is mingled with death (lack of life), and love is mingled with hate (lack of love). To find the source of truth, life, and love in this world, we cannot go to something that has limited truth, life, and love.
For example, if I were to find a source of light, I would not look under a table because light is mingled with darkness. I must go where there is pure light. So to look for the source of truth, life, and love, I must go to which is Pure Truth, Pure Life, and Pure Love and this is the definition of God. It is a job of a philosopher to make everything difficult and more abstract. Therefore we must make this argument more complex.
There is composition in this world: truth, beauty, goodness exists, and more fundamentally being. But whatever is participated is caused. Either it belongs in its own nature to possess being or it is caused by something extrinsic to it. For example, we need not look outside a triangle for its three-sidedness since a triangle has in its own nature to possess that quality.
However, a triangle does not need to be red. Other shapes can be red as well. The cause of redness must be pure redness itself. Hence, anything shared or participated is caused. We see in the world a series of contingent beings, beings that have the potentiality to exist and not exist. Since these beings are limited, it shows that it does not have in its own nature to exist for if it has in its own nature to exist, it cannot have the potentiality to not exist.
But contingent or limited beings do have a potentiality to not exist, therefore contingent or limited beings do not have in their own essence to exist. In other words, contingent beings have being, but are not being. Or to put it simply, contingent beings participate in a Being that has in its own nature to exist. This Being must be the cause of limited beings. To deny this is to say a greater can come from the less. This is absurd.
Therefore the explanation of degrees of beings participates and are caused by a First Being Who possess being most perfectly. This Being must be a necessary Being. This is what we call God.
(3) Another proof is from the order in the universe. This argument is from the principle of finality .We see agents act for an end. For example, eyes see, ears hear, legs walk, wings fly. Even more, there is some kind of unity. For example, when we hear music with different instruments with a beautiful sound that flows, we know that it is played by a band. Every instrument has an intrinsic end and an extrinsic end. For example, the intrinsic end of a flute is to play the music of a flute. The extrinsic end would be harmonizing other instruments to make some kind of harmony.
This goes on with the universe. For example, the intrinsic end of a sun is to give light or heat and its extrinsic end is to give light to a plant to make a plant grow. A plant's intrinsic end is to produce fruit and its extrinsic end is to be an animal's food. In other words, there is unity in the universe. The fact that we can see a purpose in the universe shows there is Intelligence behind it. Some may object however and say it is a process of evolution through natural selection.
However, mechanism cannot logically exclude an Intelligent Designer. Natural selection shows how things happened, not the reason why they happened. Why must the eye see and not hear? Why must the leg walk and not see? Why must the wing fly and not walk? The fact that there is unity, extrinsic and intrinsic end, shows that there must be a final cause as well as an efficient cause. The efficient cause is the power and the final cause is the reason for acting. There must be a reason why it acts in order to act.
The Efficient and Final Cause therefore, since there is unity and purpose in the universe, is an Intelligent Being. Purpose in the universe shows that there is a Mind behind it just as we know that a building's purpose is to become a cabin and we know its purpose because of the architect behind it.
(4) The last proof is not mentioned in the five ways, but is used by many theologians (i.e. Garrigou-Lagrange's 'Providence'). It is the desire for perfect happiness. We have an innate desire for perfect happiness. But we cannot find it here. Nothing less of an infinite satisfies us. All innate desires correspond to reality. I have a natural desire for food, sex, sleep, etc and there is such as those. Since there is nothing here that can satisfy us, then it is conclusive that we were made for another world. This is what we call 'life with God.'
notes: Summa Theologiae I q. 2 a. 2 reply to obj. 2
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