Gottfried Wilhelm Leibniz was a German mathematician, scientist and philosopher who made important contributions in logic, metaphysics, physics and mathematics. Even the famous French atheist, Denis Diderot, gushingly praised Leibniz as on par with Plato. Leibniz wrote about many subjects in natural theology and philosophy of religion, including the problem of evil, the cosmological argument and the ontological argument. However, what will concern us here is his cosmological argument, which can be summarized as follows.
All contingent things have an explanation for their existence
If the universe has an explanation of its existence, that explanation is God
The universe is a contingent thing.
Therefore, the universe has an explanation of its existence.
Therefore, the explanation of the existence of the universe is God.
Basically, the argument contends that everything that is contingent requires an explanation for its existence. A contingent thing is any object that might not have existed. Or, if it is logically possible (coherent to suppose) that some thing might not have existed, then that thing is a contingent being. The opposite of a contingent being is a metaphysically necessary being, or a being which could not have failed to exist. A necessary being exists in every possible scenario, which means that there is no scenario in which it does not exist. This means that it couldn’t have failed to exist.
The Principle of Sufficient Reason
Why should all contingent things require an explanation of their existence? If a particular object could have failed to exist, the question of why it does exist arises logically. For example, the chair in front of me is a contingent thing; it might have failed to exist. It would be absurd to say that the chair just exists, or that there is no explanation for its existence. But maybe we just require such an explanation because we already know that it does have an explanation. When we come across things that could have failed to exist, we will always ask why it is there. For example, imagine you are walking in a field and you come across some sort of form that is unlike anything you’ve ever seen before. Suddenly, the form starts to move and flies away across the sky until it disappears. You would not know what the explanation of this thing is. Perhaps you will think it might be a UFO, or some unknown military technology, but you would never imagine that it has no explanation – that it “just is.” This would seem to you absurd. So it is untrue that we just think there is an explanation of something when we already know what the explanation is. Everything that is contingent logically requires an explanation. The notion that all contingent things require an explanation for their existence is called the Principle of Sufficient Reason. The principle is highly intuitive, and it grounds intellectual inquiry of all sorts (including science).
Why is the explanation God?
If it is established that the universe does require an explanation, why should that explanation be God? Whatever is responsible for the universe, must transcend what the universe is made of, because whatever it is, it must have existed apart from the universe. That is, it must transcend matter, space and time. Thus, it must be immaterial, timeless and spaceless. It must also be a person. William Lane Craig notes “the personhood of the cause of the universe is implied by its timelessness and immateriality. The only entities we know of which can possess such properties are either minds or abstract objects, like numbers. But abstract objects do not stand in causal relations…Numbers, for example, cannot cause anything.”[i] Secondly, the universe cannot be accounted for by a scientific explanation, for at least two reasons. First, science explains things naturalistically. However, the universe cannot be explained naturalistically since the universe represents the totality of natural reality. It would need to be explained with reference to itself, which would just be illogical. One needs to appeal to something other than the thing needing to be explained in order to explain it. Secondly, science explains phenomena by identifying regularities or laws that operate on conditions. However, since there is nothing outside of the universe (or multiverse, whichever you prefer), it cannot be explained through regularities and laws. Natural laws “organize” preexisting material. However, those laws cannot account for how the universe came into being, because there is nothing natural outside the universe for it to organize. The only other type of explanation we are familiar with is personal explanation: explanation with reference to the intentions and actions of persons. Thus, the universe must have a personal explanation.[ii] Therefore, the universe is best explained by a timeless, spaceless, immaterial person.
You may want to say that there could be more stuff beyond the known universe (such as a multiverse) on which laws can work, perhaps even an immaterial mechanism of some sort. It need not be personal. However, this simply pushes the question further back. A multiverse will still be contingent (it is still possible for it not to have existed). An immaterial mechanism is still contingent would still have required something to start it, and since it is non-personal and cannot think, this could not have been itself.
God of the Gaps?
The argument from contingency cannot be repudiated by some scientific finding in the future. It is impossible for science to show that universe can exist in every possible world, because possible worlds are not actual. Science can only show what happens in the actual world. No manner of weird quantum voodoo, or parallel universes would be able to show, empirically, that something exists in every possible world, because anything that could be shown would by definition only be true of the actual world. So, basically, science can’t have discoveries about things that don’t actually exist (possible worlds). Nor can the argument be repudiated by finding that the universe is infinite in the past. Infinity does not imply metaphysical necessity. That is, being infinite does not imply that something could not have failed to exist. An infinite universe would still be contingent. Cosmology would need to show that there is absolutely no scenario under which the universe could have failed to exist. Science would need to show that even under fundamentally different conditions and what would count as physically impossible or absurd conditions, the universe would not fail to exist. This seems impossible, because scientists can only investigate conditions in our world, not possible conditions that are different in small or large or fundamentally different ways. Moreover, science works by inductive generalization. This implies two things. First, the scientific method generalizes based on a sample. That sample always comes from the actual world, which means that it will always be illogical to generalize the sample to possible worlds with different laws and conditions. Secondly, science can only tell us what most probably occurred – it cannot give us a deductive proof. But a deductive proof is what we would require to establish the metaphysical necessity of the universe.
Who Designed the Designer?
Wouldn’t God require an explanation as well? Why stop at God and not at the universe? In order for us to “stop” at the universe, the universe would need to be metaphysically necessary. Yet we know that the universe is contingent. We know that it is at least possible that the universe could not have existed. Thus, there must exist a necessary being apart from the universe. Why must such a metaphysically necessary being exist? For the reasons the argument already laid out. If the universe is contingent, it requires an explanation and it can’t simply exist contingently without an explanation. Technically, that thing outside the universe can also be a contingent being, but then it would also require an explanation, and the one before that, and the one before that… etc. This is what is called an infinite regress. But an infinite regress seems absurd, which is why there must be a metaphysically necessary being. ( If you want to know why an infinite regress of causes is absurd, refer to the article on the Kalam Cosmological Argument). This is precisely the basis on which the “who designed the designer objection” is levelled. The idea is that to explain the universe with reference to God fails because God himself requires explanation. But if we accept an infinite regress of contingent explanations, we run into the same problem. And the atheist is forced to accept such an infinite regress if he’s going to reject a metaphysically necessary being. So, if this problem (the infinite regress) does not apply to the atheist, it doesn’t apply to the contingency argument either. In other words, if the atheist faces the same problem without God, he can’t very well make it a reason to reject the conclusion of the argument. Apart from this the series of contingent explanations will itself still be contingent. So the whole set of contingent explanations will still be contingent even if it continues into infinity, which means that it would still require an explanation.[iii] This is simply to show that the universe itself cannot be explained without reference to some metaphysically necessary being. We know that an infinite regress is absurd, because the concept of an actual infinity is incoherent, and so we logically require a metaphysically necessary being to end the chain of explanation at some point. And even if an infinite regress were not absurd, as I’ve mentioned above, the whole infinite chain of contingent causes would still be contingent, and so still require explanation. Thus, you can never provide a complete explanation without a metaphysically necessary being.
Secondly, as William Craig has noted, this objection distorts the real nature of explanation. If an explanation is proposed, one does not immediately demand an explanation of the explanation. If you always needed to provide an explanation of every explanation you come up with, you would never explain anything at all. You would, in every instance, need to explain your explanation, and then come up with an explanation of that explanation of that explanation… ad infinitum.
Why ‘God’ and not ‘Gods’?
Why shouldn’t we think that many gods came together to design the universe? The simplest conclusion is that there is only one. If we are satisfied that the argument proves some sort of designer, there is no need to multiply entities beyond what is metaphysically required (i.e. Ockham’s Razor). The principle of ontological parsimony would counsel us that where the evidence is the same for either of the above propositions, we should opt for the simpler one: the one that postulates the fewest entities. I could similarly postulate that many gods came together and then they had a huge supernatural fight. The universe was spawned out of this celestial clash of powers. This theory explains the conclusions of cosmological and teleological arguments, but it is invalid as a conclusion precisely because we have no evidence for such a complex story (and it therefore contradicts ontological parsimony). It is therefore unreasonable to suggest that natural theologians have to rule out every logically possible scenario of creation. Similarly, scientists do not need to rule out every logically possible explanation of the evidence but can comfortably settle with the simplest one.
Fallacy of Composition
Just because everything within the universe has an explanation (and is contingent) doesn’t mean that the universe as a whole has an explanation. Doesn’t that reasoning commit the fallacy of composition? The fallacy of composition is an informal logical fallacy where something is assumed to be true of the whole because it is true of a part. For example, that part of a sofa is soft does not imply that the whole sofa is soft. Some parts of the sofa are hard (such as the legs). This is not a good objection, because we don’t need to reason from composition to show that the universe could not have existed. That is all we need to show in order to show that it requires explanation. We don’t need to say that everything within the universe requires an explanation and therefore the universe requires an explanation. Since we know that the universe could have failed to exist, the fact that it requires an explanation follows logically. But how do we know that the universe could have failed to exist? There are many things we can point to to give evidence to this claim. The fact that it began to exist means that it could have failed to exist, for example. But more fundamentally, to say that something is contingent only means that there is some possible scenario where that thing fails to exist. This is a modest claim. We just need to say that it is possible (just possible) that at some point during the Big Bang, let’s say, something went wrong and the universe didn’t come into being. Even if the universe were infinite, all you need to say is that it is possible for there to be a state of affairs where the universe does not exist. But to make it easier we’ll just focus on the fact that we know that the universe came into being as implying contingency. If something comes into being, it means that there are conditions which bring it into being. In other words, that thing is dependent or contingent upon those conditions. So we know the universe is contingent. Anybody who claims to believe that the universe began to exist, cannot avoid this conclusion unless you want to deny the scientific consensus at this time. And as we already saw, if something could have failed to exist, then the question of why it indeed exists immediately arises logically. This is strict, deductive, logical implication.
Secondly, it is important to note that the contrary viewpoint also commits the fallacy of composition. To say that it is sufficient to explain the parts of a thing and that one does not therefore have to explain the whole thing is also to commit the fallacy of composition. Or, in other words, if we say that explaining the parts of the universe sufficiently explains the universe itself, is also the fallacy of composition, because one is saying that as a result of the parts being explained, the whole is also explained. Secondly, it is not always logically invalid to reason from composition. For example, one can say that because every part of a book is constituted by paper, therefore the book itself is constituted by paper. In addition, as Bruce Reichenbach observes, the contingency of the parts of the universe makes an explanation of the whole of the universe still necessary: “If they are explained in terms of something else, the entire collection still remains unaccounted for.”[iv] This means that reasoning from composition in terms of the contingency of the universe is not logically invalid. So let us make an argument from composition for the contingency of the universe. Everything in the universe is physical and therefore impermanent, thus the universe itself is physical and therefore impermanent. The fact that everything in the universe and everything of which it is constituted is physical, means that the universe itself is also physical. The physicality of the universe is a good reason to believe that it is contingent, because physical things are impermanent. You might say that perhaps the physical things at the boundaries of reality are not impermanent. Not only is this speculation, but once again, I don’t need to rule out every logically possible scenario in order to have a compelling argument. I only need probability on my side. Given that all physical things that we’ve come across, both in our daily lives and in scientific investigation, have been impermanent, and given that the universe itself is also physical as far as we know, then it follows that the universe is impermanent.
Thirdly, to say that the argument from contingency commits this fallacy implies that one is reasoning from the parts of the universe. This is not necessarily true. This requires the assumption that the intuition underlying the principle of sufficient reason is empirically constituted. In other words, it assumes that we form this intuition by observing many contingent things that always have explanations. But this then requires the assumption that our intellectual intuitions are formed by observation, which seems to presuppose naturalism or at least empiricism (which would make this objection circular, since it assumes an epistemology that favours atheism or naturalism). We know that there are some serious problems with supposing that our intellectual intuitions are fully naturalistic (see Logos).
The world does not conform to our intellectual preferences
It is somewhat common for atheists to attempt to refute cosmological arguments by saying that our rational intuitions cannot be applied to the very macro or the very micro. Or, our rational intuitions cannot be applied to the conditions of the cosmos, because these intuitions developed in a world of medium-sized objects. For example, J.L. Mackie contends, “We have no right to assume that the universe will comply with our intellectual preferences.”[v] It is astounding that he should say this however, since the scientific method and all our reasoning about the world, is ultimately based on intuitions like those that underlie the principle of sufficient reason (which he calls our “intellectual preferences”). Daniel Dennett and the popular vlogger, Thunderfoot, make similar points when considering the arguments of William Lane Craig.
This assumes a naturalistic understanding of human beings and is therefore circular. It assumes that only natural causes are responsible for our intellectual intuitions, which assumes naturalism in order to argue for it. Secondly, this objection has a fairly absurd implication. Scientific cosmologists probably use modus ponens, modus tollens and other basic syllogisms to make conclusions about the universe as a whole. But, if our intuitions about modus ponens and modus tollens are empirically constituted and only developed through natural causes, then scientists are also doing what these atheists have said we cannot do. The intuitions of those scientists are not special – they also developed in a world of medium-sized objects. So why can scientists use those same intuitions in scientific cosmology? Scientists may have some advanced reasoning at their disposal, but all this is based on intuitions very much like the one underlying the principle of sufficient reason. In other words, no matter how advanced a mathematical theorem these scientists may deal with, they are guided at every step of implication by these basic intuitions. Scientists regularly make use of the more basic forms of reasoning in forming their conclusions. Those complex mathematical models are all based on rational intuitions which are supposedly useless when dealing with the very small or the very large. The problem with contending that our intellectual intuitions are suddenly invalidated when we deal with the “very large” or “very small” is that scientific endeavour in these areas are also then problematic.
[i] William Lane Craig, Reasonable Faith, (Wheaton: Crossway, 2008) 153
[ii] Ibid., 152
[iii] J.L. Mackie, “Critique of the Cosmological Argument,” in Philosophy of Religion: Selected Readings ed. Michael Peterson, William Hasker, Bruce Reichenbach and David Basinger, 4th ed. (New York: Oxford University Press, 2010), 205.
[iv] Reichenbach, Bruce R., “The Cosmological Argument,” in Philosophy of Religion: Selected Readings, ed. Michael Peterson, William Hasker, Bruce Reichenbach and David Bassinger, 4th ed. (New York: Oxford University Press, 2010), 193.
[v] J.L. Mackie, The Miracle of Theism, p. 87