In recent times, there has been increasing skepticism, especially among the New Atheism proponents, concerning the causal principle: whatever is caused is caused by another. Many of the arguments for God’s existence rely on this principle, such as the five ways of Thomas Aquinas and the Kalam cosmological argument, which argues for the existence of a creator in light of the beginning of time and physical reality.
It is therefore unsurprising that atheists are trying to find a way around the causal principle. Of the various forms that the causal principle takes, the one that modern atheists most frequently question is: “Whatever begins to exist must have a cause of its existence.”
For example, Quentin Smith, a professor of philosophy at Western Michigan University, writes, “The most reasonable belief is that we came from nothing, by nothing, and for nothing” (Theism, Atheism, and Big Bang Cosmology, 135). In a debate with Australian cardinal George Pell in 2012, Richard Dawkins, perhaps the most famous proponent of the New Atheism, asserted:
Of course it’s counterintuitive that you can get something from nothing! Of course common sense doesn’t allow you get something from nothing! That’s why it’s interesting. It’s got to be interesting in order to give rise to the universe at all!
Smith and Dawkins are in good company with the late Australian philosopher J.L. Mackie, who said, “There is a priori no good reason why a sheer origination of things, not determined by anything, should be unacceptable” (The Miracle of Theism, 94).
If it is common sense that something cannot come from sheer nothingness, as Dawkins states, then why are these men of such intelligence denying common sense? Let’s take a look at some possible reasons.
Hume’s “imagination argument”
Modern philosophers often attempt to justify the assertion that something could begin to exist without a cause by appealing to David Hume’s “imagination argument.” Hume called into question the certainty of the causal principle by suggesting the possibility that something could come into being without a cause. He attempted to justify his position by asserting that one can imagine something coming into existence without a cause.
For example, you might imagine the surface of a table with nothing on it, then you imagine a billiard ball suddenly appearing on it. Hume’s reasoning is that since one can imagine something beginning to exist without imagining a cause, then it must be at least possible that no cause is needed to bring something into existence; thus the causal principle, according to Hume, is not certain.
How can we respond?
First, his objection rests entirely on the false notion that our imagination serves as an accurate yardstick for determining what is possible in the real world. Consider again Hume’s basic argument: If we can imagine the billiard ball popping into existence on the table without imagining its cause, then its possible for the billiard ball to appear on the table without a cause. In other words, for Hume, whatever is separable in the imagination can be separated in reality.
This is simply not true. Consider the following example. I can imagine Barney, the purple dinosaur, dancing without imagining a person inside the costume. This is what children do. But does that mean it is possible for Barney to act and sing without an actor in the costume? According to Hume, we would have to answer yes. But this is absurd. We know that an actor is needed inside the costume to make Barney dance.
Furthermore, I can imagine Optimus Prime fighting the evil Decepticons on the big screen without imagining the computer-generated imagery technicians that created these characters. Does that mean these characters can actually be present on the screen without the work of CGI technicians? The answer is no. Just because one can imagine a thing to be in such and such a way does not mean it can really be that way. Therefore, Hume’s imaginative experiment does not undermine the certainty of the causal principle in the form whatever begins to exist must have a cause.
A second objection against Hume is that there is nothing in his imaginative situation that necessitates the billiard ball having no cause as opposed to a cause that cannot be imagined. Recall that Hume’s argument entails merely imagining the effect without imagining the cause. But, as Michael Augros argues in appendix two of his book Who Designed the Designer? A Rediscovered Path to God’s Existence, perhaps there are causes that by nature cannot be imagined. Such causes could be elementary particles, forces of nature like gravity, or entities that go beyond the material realm, such as God or angels.
Now, if there are causes that are by nature not subject to the imagination, then the mere fact that we fail to imagine them when we imagine an effect (e.g., the billiard ball appearing on the table) does not prove that the effect can happen without the unimaginable cause. It simply points to the fact that the cause of the billiard ball appearing on the table might be something we cannot imagine.
But if this is true, then Hume’s argument does not achieve what it sets out to achieve—namely, that something can begin to exist with no cause. Therefore, there is no need for one to doubt the causal principle based on Hume’s argument.
Virtual particles example
Another rational justification for the atheist’s claim that something can begin to exist without a cause comes from quantum physics. Within the study of quantum physics, scientists have observed so-called “virtual particles,” particles that pop into existence apparently without a cause and then immediately cancel each other out, resulting in residual radiation within an empty vacuum (a vacuum in quantum field theory is a quantum state with the lowest possible energy generally devoid of physical particles except for the “virtual particles”).
Many atheists see this phenomenon as rational justification for denying the causal principle. For example, Lawrence Krauss, an American theoretical physicist and cosmologist, wrote a book on this subject titled A Universe from Nothing: Why There is Something Rather than Nothing. How is a supporter of the causal principle to respond?
First of all, the quantum vacuum in which these particles are “popping into existence” is not nothing (the absence of being) but something. This vacuum state is a low-level quantum energy field that is subject to the physical laws of nature. The virtual particles that “pop into existence” are a result of the fluctuations of energy within this quantum vacuum. In a New York Times book review of Krauss’s book, Columbia University philosopher and theoretical physicist David Albert writes:
[V]acuum states—no less than giraffes or refrigerators or solar systems—are particular arrangements of elementary physical stuff. . . . [T]he fact that particles can pop in and out of existence, over time, as those [quantum] fields rearrange themselves, is not a whit more mysterious than the fact that fists can pop in and out of existence, over time, as my fingers rearrange themselves. And none of these poppings—if you look at them aright—amount to anything even remotely in the neighborhood of a creation from nothing (“On the Origin of Everything: ‘A Universe from Nothing’ by Lawrence Krauss,” The New York Times, March 23, 2012).
So one might conclude that those who appeal to the activities within a subatomic vacuum state are equivocating on the term nothing—sneaking something into nothing rather than just letting nothing be nothing, thus nullifying their argument against the causal principle of whatever begins to exist must have a cause.
Since the rational justifications for denying the causal principle do not stand to the scrutiny of reason, the question arises, “Is it possible to offer positive arguments in defense of the causal principle?” There are two arguments, in this regard, that I think succeed.
Existence and nonexistence
The first argument takes into consideration the fact that whatever begins to exist is what St. Thomas Aquinas calls a possible being—something whose nonexistence is a possibility (see Metaphysics, book IX, lesson 3). This is obvious, given the fact that whatever begins to exist at one time did not exist.
Now, in the Thomistic tradition, whatever is a possible being does not possess its act of existence by nature. This means that existence—that a being is—does not belong to a possible being’s essence—what it is.
Consider the example of a house. Prior to a house being built, the carpenter can ponder the essence of the house (what it is) without it having real existence in the world outside his mind. Notice that the mere thought of the house does not necessitate its existence in the real world. This means that existence does not belong to the essence of the house.
Think of a triangle by way of contrast. It is impossible to think of a triangle without thinking of a figure with three straight sides. This is so because the idea of three straight sides belongs to the essence of a triangle. The house, on the other hand, can be thought of without it existing in the real world. Therefore, the houses’ existence does not belong to the essence of the house—they are distinct. As some philosophers put it, knowing what it is does not determine that it is. This is why the house is merely possible.
Furthermore, when the carpenter builds the house and gives it real existence, the essence of the house does not change. The house’s act of existence—that it is—makes no difference to its essence—what it is.
Contrast this with the aforementioned triangle. The idea of three straight sides does make a difference to the essence of a triangle. Why? Because the idea of three straight sides belongs to the essence of a triangle—they are one and the same.
But in the case of the house, its existence (that it is)—whether merely in the mind of the carpenter or in the real world—makes no difference to its essence (what it is). As such, its existence does not belong to its essence—that is to say, its act of existence is nonessential, making the house a possible being.
So, in light of the house example, we can conclude that whatever being is a possible being—a being that begins to exist—does not possess its act of existence by nature. From this it follows that we cannot conceive of such a being having its act of existence in virtue of what it is in itself. In other words, we cannot appeal to a possible being’s essence to distinguish it from nothing.
Consider the house again. Can the essence of the house account for it existing in the real world as opposed to being nothing? It cannot since the essence of the house does not contain its act of existence (as demonstrated above). The house, therefore, and every other possible being, cannot be the reason for its distinction from nothing. With this in mind, the absurdity of claiming that something can begin to exist without a cause becomes apparent.
Something or nothing at all
If a possible being’s essence cannot distinguish it from nothing, then the only two options that remain are 1) something outside itself, a cause, or 2) nothing at all. The skeptic who denies the causal principle obviously rejects the former. Consequently, denying the causal principle is tantamount to saying that nothing distinguishes a possible being from nothing—i.e., its distinction from nothing comes from neither itself nor anything else. But how can a possible being exist and simultaneously not be distinguished from nothing? It can’t! Something cannot be distinguished from nothing and not be distinguished from nothing in the same respect at the same place and time. The denial of the causal principle, therefore, leads to a contradiction and thus is unreasonable—proving its affirmation to be reasonable.
The second argument in defense of the causal principle is similar to the first in that it is based on the distinction between essence (what something is) and existence (that something is). The fact that existence does not belong to the essence or nature of possible beings (things that begin to exist), one must conclude that it is non-essential and thus an accident for possible beings. “Accident” here does not refer to a car crash but to an attribute that may or may not belong to something without affecting its essence. As the late Fr. Joseph Owens points out in his book, An Elementary Christian Metaphysics, “whatever there is in a thing outside its nature belongs to it accidentally” (pg. 71). For example, three straight sides belong to the essence of a triangle but the color red does not. The color red is non-essential and thus is an accident for the triangle. Similarly, because existence is non-essential in possible beings—it may or may not belong to a possible being’s essence—it is considered an accident for possible beings.
Now, not only is existence accidental to the essence or nature of possible beings, it is also ontologically prior (coming before in the order of being). This is just a fancy way of saying that an essence that actually exists in the real world (e.g., a house or a dog) presupposes existence itself—that is to say without it an essence would not be real. For example, my act of existence makes the essence of man actual in me rather than it being a mere abstraction in a mind.
The same goes for Fido’s act of existence, which makes the essence of dog actual in Fido. There can be neither an act of being a man nor an act of being a dog without existence. The bottom line is that without existence the essence of possible beings (e.g., Fido and me) would not exist. Existence, therefore, is an ontologically prior accident for the essence of things that begin to exist.
“But,” one might ask, “What’s the big deal?” The big deal is that it serves as the basis for defending the causal principle. Consider that whatever is accidental does not exist in its own right, but is dependent upon a substance. For example, color does not exist in its own right. Red is not floating somewhere in the cosmos. It can only exist in something, such as a triangle or a crayon. Now, if existence is an accident in possible beings, then it must be dependent upon a substance. But it (existence) cannot be dependent upon the substance that it makes actual. For example, Fido’s existence cannot depend upon Fido’s essence because, as already demonstrated, existence is prior to essence. Without the act of existence, the essence of dog would not be made real in Fido. Therefore, the act of existence for a possible being must be dependent upon—received from—something other than the thing that it makes actual or real. Now to give existence to something (to make it real) is simply to be a cause. Therefore, everything that begins to exist must have a cause for its existence.
In conclusion, the rational justifications for denying the causal principle in the form of “whatever begins to exist must have a cause” are not grounds for undermining the force of theistic arguments of the likes of St. Thomas Aquinas and the Kalam cosmological argument. Furthermore, there are good positive reasons to hold to the causal principle considered in this article as true. Thus, the causal principle stands on solid ground and the light of philosophical theology continues to lead the way for sojourners on the journey to theism.