Skip to main contentAccessibility feedback
Background Image

A Rational Approach to God’s Existence

It seems to be the pervasive view today that atheism has the intellectual high ground over theism. Belief in the existence of God is perceived as naïve or intellectually shallow. Atheists tend to think that all arguments for the existence of God are “god of the gaps” arguments that posit God to fill in the gaps created by a lack of natural explanations for certain phenomena. This leads atheists to define acceptance of God as belief without evidence—a sort of blind impulse of the mind, appalling to an intellectually responsible individual.

But this thinking is wrong. “God of the gaps” arguments are not representative of traditional theism as embodied in Catholic Tradition. Many philosophers of the classical bent would agree with atheists in rejecting such arguments and view them as not worthy of being classified as proofs of God’s existence. Classical theism sees God as that which is metaphysically necessary to account for the existence of things within the universe (and the universe as a whole).

For this reason, it’s imperative that we as Catholics learn to employ arguments for God’s existence that vindicate the Church’s teaching that “God, the first principle and last end of all things, can be known with certainty from the created world by the natural light of human reason” (Vatican Council I, Dei Filius 2).

Conditions necessary for existence

One such argument is based on the notion of ontological conditions—conditions that are necessary for things to exist. The argument can be divided into two parts. The first part considers an argument for why there must be at least one unconditioned reality in all of reality (traditionally called an uncaused cause). The second part of the demonstration consists of ways to deduce various attributes that classically have been attributed to God.

Let’s start with why there must be at least one unconditioned reality in all of reality by elucidating the range of possibilities for all of reality by establishing what philosophers call a “disjunctive syllogism” (see sidebar, p. x).

As Fr. Robert J. Spitzer points out in his book New Proofs for the Existence of God, in all of reality there is either at least one unconditioned reality (a reality that does not need any conditions fulfilled in order to exist but exists by its very nature—a reality that exists in and through itself), or else there is no unconditioned reality. In the latter case, all things in reality would need conditions fulfilled in order to exist.

For the sake of brevity, we’ll follow Fr. Spitzer’s lead and call the first side of the disjunction hypothesis UR (at least one unconditioned reality in all of reality) and the other side hypothesis ~UR (no unconditioned reality in all of reality).

Now, because these two hypotheses exhaust the entire range of possibilities in all of reality, one has to be true and the other has to be false. They cannot both be true and they cannot both be false. If we can prove that hypothesis ~UR is false, we will have proven that hypothesis UR is true.

Another disjunction

In order to make navigate more easily through the argument, let’s formulate another disjunction for hypothesis ~UR:

If there is no unconditioned reality in all of reality, then a conditioned reality (e.g., a cat) is going to depend either on a finite number of conditions where every condition is a conditioned reality (hypothesis F) or an infinite number of conditions where every condition is a conditioned reality (hypothesis ~F).

The thrust this part of the argument is to show that neither hypothesis F nor hypothesis ~F can be true. Since hypothesis F and hypothesis ~F elucidate all the possibilities for reality under hypothesis ~UR, if hypothesis F and hypothesis ~F can be proven false, then hypothesis ~UR must be false as well.

Finite conditions

Let’s begin by showing that hypothesis F—the cat is dependent on a finite number of conditions where every condition is a conditioned reality—is false.

First, if the cat is dependent on a finite number of conditions, there is going to be a most fundamental condition (a last or terminal condition) in the series of conditions that the cat depends upon for its existence. For example, the cat depends on the existence of its cells, which in turn depend on amino acids and proteins, which depend on the existence of molecules, which depend on atoms, which depend upon protons, which depend upon quarks, and so forth. With such a series, the quark (or something more fundamental, whether material or immaterial) would be the terminating condition the cat depends on for its existence.

Since hypothesis ~UR asserts that there are no unconditioned realities in all of reality and only conditioned realities exist, this most fundamental or last condition in the series would have to be a conditioned reality, which means it must have its conditions fulfilled in order to exist. But this conditioned reality could not have its conditions fulfilled, since it is the most fundamental condition (remember, hypothesis ~UR doesn’t allow for unconditioned realities).

Now, if this most fundamental condition of the cat is a conditioned reality whose conditions cannot be fulfilled, it would be nonexistent (nothing). Consequently, every other conditioned reality dependent on it would be nonexistent as well, including the cat.

But the cat does exist. Therefore, the cat cannot be dependent upon a finite number of conditions where every condition is itself a conditioned reality. Hypothesis F is false.

Infinite conditions

What about hypothesis ~F? Could the cat be dependent upon an infinite number of conditions where every condition is a conditioned reality? Again, the answer is no. If the series of conditioned realities—cells, amino acids and proteins, molecules, atoms, protons, quarks, etc.—on which the cat’s existence depends regresses infinitely, then every hypothetical conditioned reality in the series would never have its conditions fulfilled, which is another way of saying it would not exist.

Therefore, the cat would be dependent upon a series of nonexistent conditions. But for the cat to depend upon a series of nonexistent conditions would mean that the cat would not exist. But the cat does exist. So we know that hypothesis ~F is false.

Now, recall that we initially elucidated all the possibilities for hypothesis ~UR with hypothesis F and hypothesis ~F. If hypothesis F and hypothesis ~F are false, then hypothesis ~UR is false. As we demonstrated, hypotheses F and ~F are false; therefore, hypothesis ~UR must be false.

Furthermore, because we elucidated by way of a complete disjunctive syllogism the whole range of possibilities for all of reality with hypothesis ~UR and hypothesis UR, it follows that since hypothesis ~UR is false, hypothesis UR must be true. That is to say, any conditioned reality (e.g., the cat) must have its conditions fulfilled by at least one unconditioned reality (a reality that does not depend upon the fulfillment of any conditions for its existence).

Is the unconditioned reality God?

But is such a reality worthy to be considered as what theists have traditionally defined as God? Can there be more than one unconditioned reality? Can such reality be bound by space and time? These questions bring us to part two of the argument.

The first thing we notice about unconditioned reality considered in and of itself is that it must be unrestricted being—pure being or pure existence itself (what St. Thomas Aquinas called ipsum esse subsistens, or “subsistent being itself”).

The first step to understanding unconditioned reality as unrestricted being itself is to think about how the realities of our experience have particularmodes of being. They have distinguishing notes or diversifying principles that makes them this being instead of that being.

These distinguishing notes or diversifying principles constitute what philosophers call restrictions or boundaries. Such restrictions can be spatial (X exists here instead of there), temporal (X exists now instead of then), or a way of existence (X exists and behaves in this way—the way of an electron for example—instead of that way, the way of a proton).

Now, for any reality X that has any of the aforementioned restrictions, there exists a wide range of other possible modes of being. For example, if the tree exists here, then there exists the real possibility that it could have existed there. If the tree exists now, then there exists the real possibility that it could have existed then. If the tree exists in this way (e.g., the pine tree way), there is the real possibility that it could have existed that way (the oak tree way).

Why?

In such a case, the question necessarily arises, “Why is it so?” For example, why does reality X exist this way instead of that way? Why does reality X exist here instead of there? Why does reality X exist now instead of then? Because there are other possible modes of being to which X could have been restricted, we must ask why X does not have that mode.

Such questions presuppose some principle of selection or cause outside of reality X itself that selects or determines the mode of being that X has. Reality X can’t select its own limited mode of being, because to do so it would have to exist its own being, in which case it would be existing and not existing in the same respect at the same place and time. Obviously, this is a contradiction and thus cannot be true.

Therefore, any reality X that is restricted in its mode of existence is going to be conditioned by some principle of selection outside itself.

Unconditioned = unrestricted

We must then ask the question, “Can unconditioned reality considered in and of itself be limited or restricted in its act of being by any of the aforementioned restrictions?” In other words, Can unconditioned reality be restricted to existing here instead of there (spatial restriction); or now instead of then (temporal restriction); or this way instead of that way (existential restriction)? In light of our previous reasoning, the answer must be no.

The argument for such a conclusion goes as follows:

Premise 1: If X is restricted by space, time, or a way of existence, then it necessarily would be conditioned by a principle of selection that determines its restricted mode of existence.

Premise 2: Unconditioned reality cannot be conditioned by anything.

Conclusion: Therefore, unconditioned reality cannot be restricted in its act of existence by space, time, or a way of existence.

Notice with this conclusion we arrive at three key attributes that have been classically ascribed to God. First, if unconditioned reality cannot be restricted by space, then unconditioned reality must be immaterial, since all matter has extension in space. Secondly, if unconditioned reality cannot be restricted by time, then unconditioned reality must be atemporal or timeless, i.e., eternal. Thirdly, if unconditioned reality cannot be restricted to a particular wayof existence, then it must be pure existence or pure being itself—what philosophers call absolute simplicity.

So we have a reality that is unconditioned, absolutely simple, immaterial, and eternal. The only attribute left that is needed to make a definitive conclusion that such a being is worthy of the traditional term “God” is unicity—namely, that there can be one and only one (other Godly attributes such as immutability, perfection, omnipotence, omnibenevolence, and omniscience follow from the above attributes).

Can there be more than one “God”?

Consider for argument’s sake that there are more than one instantiation of unconditioned reality. For the sake of brevity, we will call them UR1 and UR2. Now, in order to have multiplicity, we are going to have to differentiate UR2 from UR1; otherwise they would be the same and therefore one.

The difference implies a distinguishing note (an instantiating factor) or some principle of dissimilarity. In other words, there would have to be some factor that differentiates UR2 from UR1 and makes UR2 a particular or distinct instantiation of unconditioned reality.

We normally distinguish modes of being by factors such as space, time, or a way of existence. For example, this tree exists here and that tree exists there. This tree existed before (or after) that tree. This tree exists as a pine tree and that tree exists as an oak tree.

So, if UR2 is to be distinguished from UR1, then UR2 must be different than UR1 due to a position in space (not existing somewhere where UR1 is), or a point in time (not existing at a time when UR1 does), or a way of existence (not existing in the way that UR1 exists).

Given this hypothetical state of multiple instantiations of unconditioned reality, we can now show why it is metaphysically impossible to have multiple URs.

First, to differentiate UR2 from UR1 by space, time, or a way of existence is to restrict its mode of existence. For example, if UR2 is differentiated by space, then its’ going to be restricted to existing here and not there. If UR2 is differentiated by time, then it’s going to be restricted to existing now instead of then. If UR2 is differentiated by a qualitative difference, then it’s going to be restricted to existing in this way instead of some other way.

But, as we’ve already demonstrated, unconditioned reality cannot have any restrictions whatsoever in its mode of existence. Otherwise it would be conditioned by some principle of selection outside itself, which is impossible.

Therefore, UR2 cannot be differentiated from UR1;for the moment we try to do so, UR2 ceases to be unconditioned reality (the same reasoning applies for any hypothetical multiple instantiation of unconditioned reality). Therefore, there can be only one unconditioned reality.

In conclusion, we’ve arrived at a reality that is unconditioned, absolutely simple (pure being or pure existence), immaterial, eternal, and absolutely unique. I think such reality is worthy of the traditional term God.

Did you like this content? Please help keep us ad-free
Enjoying this content?  Please support our mission!Donatewww.catholic.com/support-us