copyright © 2012 Dennis Paul Himes

Modal Realism and the Argument from First Cause

This is a slightly edited version of a talk I gave at a Humanist Association of Connecticut dinner on 24 July 2012.

As someone who has been a public promoter of Atheism for almost a decade now, I have been contacted by more than my share of Theists trying to convince me of the error of my ways. I pretty much expected this, and in a way welcomed it, since the existence of gods is an important subject which should be discussed openly a lot more than it is. However, I soon discovered that the arguments which are used by the kind of Theists who like to engage Atheist activists in debate tend to be really lame. There are those who quote the Bible, apparently thinking that Atheists accept the authority of the Bible but just don't realize that the Bible says there's a God. There are those who assume that human intuition can never be wrong, and therefore feeling the presence of God is proof that he exists. There are surprisingly many who use the argument from design, which at least has the virtue of having once been a reasonable argument, about two centuries ago. And this isn't even considering arguments such as Pascal's Wager, which aren't really arguments for believing in God's existence at all, but rather for pretending to believe in it.

This is a shame, because while all arguments for God are ultimately flawed, they are not all as lame as these. There are arguments for God which require a little thought to see the flaws within, which actually pose something of an intellectual challenge for the Atheist wanting to defend his position. It was these arguments which caused me to call myself an Agnostic during my early twenties. It was these arguments I devoted the bulk my online essay, An Atheist Apology, to. In that essay, written several years before 9/11 turned me into an activist, I only wrote two sentences on the argument from design, because I didn't see the point of belaboring the obvious.

I did devote a lot of the essay, however, to discussing what is in my opinion the best argument that Theists have, the argument from first cause. Why does the universe exist? Why is there something rather than nothing? The Theist claims that there must be a first cause, prior to all effect, and that that cause is necessarily a sapient being. There is a common refutation of this argument which shows that the Theist solution to the problem isn't really a solution, but which I always found somewhat unsatisfying, because it still left the problem unsolved. My conversion from an Agnostic to an Atheist came when I realized that the problem itself is flawed; it makes a false assumption, a category error which renders it moot.

First, the common refutation and why it's unsatisfying. Most Theists making this argument assume a priori that it's a fundamental principal that every effect has a cause. The Atheist will then ask him was is the cause of God. The Theist will then say that God is an exception to the rule, thus denying the philosophical principal his whole argument is based on, rendering it invalid. Other Theists have thought this through more, and will only claim that natural phenomena necessarily have causes. They used to assume a priori that the universe had a beginning, but now point to the Big Bang as evidence of that. Unfortunately for them, the Big Bang was the beginning of time, which means that it can't have a cause, since a cause would have to exist earlier in time. Asking what happened before the Big Bang is like asking what's on the surface of the Earth north of the North Pole. Besides, if a natural phenomenon has a cause, that cause is ipso facto a part of nature as well. "Supernatural phenomenon" is a contradiction in terms.

So the Theist explanation for why the universe exists is unsatisfactory, but what can we replace it with? Before we can answer that we have to be clear on what the word "exist" means in this context. The reason this is important is that when people, both Theist and Atheist, ask why the universe exists they are using the word "exist" in a different way than how that word is used in ordinary day-to-day conversation. Usually we use the word "exist" to mean "be a part of the universe in which we find ourselves". By that definition, however, asking "why does the universe exist" is like asking "why are even numbers divisible by two". The answer in both cases is, "because that's what the word means".

However, when people talk about the universe existing, they mean that this universe has some property that other logically consistent possible universes don't. What is that property? Well, they call it "existence", but it's not the existence I just described, or else "the universe exists" would just mean "this universe is part of this universe", which is just a tautology. When people talk about the universe existing, however, they're clearly talking about some alienable property. In other words, it would have in some way been possible for this universe to not exist. It would have been possible for this universe to just be a potential, but not an actual, universe. My contention, counter-intuitive as it might be, is that this is an illusionary distinction. There is not, and cannot be, any distinction between a potential universe and an actual universe. And when there's no possible distinction between two states, even in theory, then they're just two different names for the same thing.

If you're now thinking, "Well, I know this universe is real, or else I wouldn't be sitting here listening to you", consider that a potential you in a potential version of this universe would potentially be sitting in a potential Hanafin's Pub potentially listening to a potential Dennis Himes, and that potential you would have a potential brain, which would potentially think the thought, "Well, I know this universe is real, or else I wouldn't be sitting here listening to you".

The universe is a set of rules, known as the laws of physics, applied to a set of conditions, know as stuff (or matter and energy), and the statement "These rules applied to these conditions result in these new conditions" is true whether or not the rules and conditions are real or some hypothetical possibility. Those changing conditions include your brain, your thoughts, and your experiences. The rules and conditions of this universe, whether or not it's actual or potential, result in you sitting in Hanafin's Pub listening to me speak this sentence and thinking whatever it is you're thinking. Even if you think there is a real distinction between an actual and a potential universe, there is no way even in theory you can determine whether or not the thoughts you are thinking and the experiences you've had are actual thoughts and experiences of an actual person or the potential thoughts and experiences of a potential person. Even if you had all of the resources of the universe at your disposal, there is no experiment you could conceivably make which would distinguish between this universe being actual and this universe being potential. My claim is, if two things are not different, then they're the same.

Keep in mind that the more common meaning of existence, i.e. being part of this universe, does have real meaning, because whether or not something is a part of this universe can be determined.

One type of question I often get about this is some variation of, "Does this mean you believe that the Middle Earth of the Lord of the Rings is as real a world as this one?", to which my answer is, "maybe". It all depends on whether or not Tolkien's vision is consistent, or, rather, whether or not there is some consistent universe which Tolkien's fiction correctly describes a part of. I doubt it, myself, since it's clear that Tolkien assumes that the physics of the Middle Earth closely tracks the physics of ours, and I'm not at all convinced that that's compatible with magic. Since so much of his world is implied and not stated, though, it's hard to say. Keep in mind though, that if it is a potential universe, then it's only real relative to itself, just as we are only real relative to ourselves; it's imaginary relative to here, just as we would be imaginary relative to there.

So what are the theological implications of this? The most obvious is that the idea that God created the universe no longer even makes sense. Since there's no difference between a potential and an actual universe it doesn't make sense to say that God converted a potential universe into an actual one, which is what creation means. This is what I mean when I say that the question of the universes creation is a category error.

The nuns who taught me in grade school planted the seed of this idea, although neither they nor I realized all of the implications at the time. Still, I was taught that the universe exists in the mind of God, and that if God ceased thinking of us we would cease to exist. What we didn't consider is that God would be omniscient, so all possible potential universes would be in his mind. If there were a God he would always be aware of every aspect of every universe, and for him to consider one "real" would just be to assign an arbitrary label to it. So even if there were a God, in the sense of an omnipotent being, to say he created the universe wouldn't make sense.

I'm not claiming, however, that this in itself disproves the existence of gods, or even that it means that a god or gods could not have had something to do the early history of the universe. Perhaps the rules and conditions of this universe include a very powerful eternal intelligence who arranged the early stuff so that the rules would result in what we see today. Well, in that case god, powerful as he might be, would be part of the universe and therefore a natural phenomenon. We have ways to detect natural phenomena and to figure out which earlier phenomenon caused which later one. It's called science. It's science which shows us that there's no god affecting the workings of the universe in the present era, because if there were else the universe we observe would be different than it is. So the question becomes, "are our observations consistent with the hypothesis that an intelligence set things in motion fourteen billion years ago, or not?"

There was a time when the answer to that wasn't clear. It was never clearly "yes it is", but "no it wasn't" had a serious problem. Either the universe existed infinitely into the past, or it had a beginning. Observed phenomena were not consistent with an infinite past, in particular the fact that it's dark at night, known as Olber's Paradox. If the universe were infinite in time as well as space the night sky would be as bright as the sun, due to distant starlight. A finite past had its own problems, too. If you run the laws of physics backwards far enough you should arrive at a state of the universe before any given time, which would contradict the hypothesis that that time was the beginning of the universe. The solution to this problem was so elegant that it's a wonder no one thought of it before it was discovered by observation. It turns out that if you run the laws of physics backwards the universe arrives at a singularity, where everything is at a point of infinite density, known as the Big Bang. Since it's a singularity, the laws of physics make no prediction for what happened before, so there's no contradiction. As I said, talking about before the Big Bang is like talking about north of the North Pole.

Now, some Theists have claimed that the rules of our universe themselves point to an intelligent creator. They point out that there are many physical constants whose values seem otherwise arbitrary which seemed to be fine tuned to allow for the development of intelligent life. If some of these were only slightly different, for instance, then stars and planets could not have formed. Therefore, they say, the evidence points to a creator, since it would be too much of a coincidence for the laws of physics to just happen to allow for life to form. This is known as the Strong Anthropic Principle. However, when you consider that, as I have just demonstrated, all potential universes are as real as each other, then it ceases to be a coincidence at all, and it's merely a tautology that a universe which produces intelligent beings is one of the subset of possible universes which are capable of producing intelligent beings. I was not the first one to realize this; while not following my exact reasoning, very similar formulations have been put forth, under the name of the Weak Anthropic Principle.

So, I realized the core concepts of what I've been discussing sometime in the mid 1970s, and that's when I started considering myself an Atheist instead of an Agnostic, since it removed the last plausible justification I had ever heard for the hypothesis that there's a supreme being. At the time, I had never heard of this line of reasoning from anyone else, but, of course, it came as no surprise that similar ideas have been put forth by others. In particular, when I put my Atheist Apology essay online in the late nineties, several people commented that I was obviously influenced by David Kellogg Lewis. However, I had never heard of him. When he died in 2001, though, I read the description of his work in his obituary, and it was clear why people thought I was his follower. I have since read his book On the Plurality of Worlds. He argues for many of the same ideas as I do, under the name of modal realism. The main difference in our thoughts, as far as I can see, is that he argues for adopting modal realism because, "the hypothesis is serviceable, and that is a reason to think that it is true". I would go further, and say not only that modal realism is useful and noncontradictory, but that the rejection of modal realism is ultimately incoherent.

Let me leave you with a quote from Lewis, "I once complained that my modal realism met with many incredulous stares, but few argued objections. The arguments were soon forthcoming. ... I think they have been adequately countered. ... The incredulous stares remain." I know how he felt. I hope I have given you food for thought, though, and if my version of modal realism leaves you incredulous, you will nonetheless consider it on its merits.

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