Last night, I took part in an open panel discussion between Christians and atheists. This was an event organized by Faith Ascent Ministries, which teaches apologetics to teens. It was billed as an opportunity for those kids, their parents, and anyone else interested to come and ask questions, hear answers from both atheists and Christians, and actually get to meet some atheists in the flesh. That’s a goal I can wholeheartedly support, so I was happy to be there. When studies show that religious people distrust atheists as much as rapists, something has gone wrong. There clearly is a need for us to come together, help foster understanding, and dispel popular misconceptions. I tried my hardest to be engaging (even though anyone who knows me will recognize I’m really a curmudgeon at heart), and I felt like I was warmly received and that the Christians genuinely appreciated what I had to say. They even laughed at my jokes, so now I can prove to my wife that someone other than my 3-year-old thinks I’m funny!
I was on the atheist side of the panel, of course, along with a fellow graduate student in philosophy and a law student. We were like Shadrach, Meshach, and Abednego. The three Christians were a Professor of Modern Christianity at St. Louis University, an apologist trained at Biola University, and a member of the Concerned Women for America. The audience appeared to be mostly Christian, but not entirely. The moderator was also Christian, but I don’t think he acted in a way that favored any one side. This was not set up as a debate, even though we engaged in quite a bit of point-counterpoint. Instead, it was arranged as a discussion around four categories, each handled in turn, and after we kicked off our initial thoughts in each category it was open to the audience to ask follow-up questions. The four topics of discussion were origins, purpose, morality, and the best arguments for/against theism. I want to use this forum as an opportunity to merely provide some closing thoughts on each area because we were all trying to allow everyone time to speak and this naturally leaves a lot of points on the table. This time I’ll discuss cosmic origins and I’ll use later posts to recap the other areas.
My side of the panel had discussed in advance that I would tackle the issue of cosmic origins and the other two would focus on biological origins. I presented the overview of my stance on cosmic origins as follows:
- Narrow naturalism is a view that is incredibly well justified. This is basically the view that for any given event—someone getting sick, a car running out of gas, a planet orbiting a star—it is overwhelmingly likely that event has a natural explanation. No one thinks their car ran out of gas because it was siphoned out by a demon.
- Barring any special reasons for making an exception, this narrow naturalism will apply to any given event in the natural world.
- It is claimed by theists that some events do have special reasons for making an exception. One example would be cosmic origins. Two examples of special reasons they might propose would be the Kalam Cosmological Argument and the Fine Tuning Argument.
- I find both arguments problematic.
- Therefore, I maintain that even without a precise explanation for our cosmic origins, I am still justified in maintaining that it probably has a naturalistic explanation.
Now, sure enough issues relevant to both Kalam and Fine Tuning were presented by the other side. However, I went first and didn’t have a chance to respond to specifically why I find both arguments problematic. I’ll offer a few of those reasons here.
Fine Tuning Argument
There are variations on the fine tuning argument, including setting the problem up as a Bayesian inference (most popular), an appeal to the best explanation, or an appeal to likelihood (this is like being a Bayesian without accounting for prior probability). Whatever form it takes, the argument seems most persuasive to people when it is portrayed as a situation in which the various constants and parameters of our universe are unlikely to have occurred on their own. They are, in other words, improbable given naturalism.
I’m going to offer what I think is the strongest one of several options that might undercut this argument. Let’s take a specific example to help illustrate the problem here. If the strong nuclear force differed by a significant amount, then atoms would not be able to stay together and instead of ‘things’ being able to form as we know them, the universe would likely be composed of some kind of atomic soup.
When you look at this problem, you might notice that the formal conditions for even speaking of probability are not met. What are the possible ranges these parameters could have taken? We don’t have a sample space defined! If you think about probability in its simplest form, the sample space is the denominator. The chance of rolling a 5 on a fair six-sided die is 1/6. The 6 represents the total number of possible outcomes. This is basically found by adding the one option (from the numerator) that affirms what we want—rolling a 5—to the disconfirming options that would give us a different result—rolling a 1, 2, 3, 4, or 6. We are being told that we need to have rolled a 5 for the universe to exist, but not being told how many sides there are to the die.
Consider the following quote from physicist Paul Davies in The Mind of God:
“The problem is that there is no natural way to quantify the intrinsic probability of the known coincidences. […] If the range is infinite, then any finite range of values might be considered to have zero probability.”
Since we don’t have a sample space adequately defined, we are left with trying to use logical possibility as the way to determine the other possible options. Using logical possibility means we are considering every real number an option, which is infinite.
This is what Evangelical husband and wife Christian philosophers Tim and Lydia McGrew, along with Eric Vestrup, call the Normalizability Problem. As Davies said, standard probability theory gives a probability of zero when in relation to an infinite reference class. This means, as the McGrews and Vestrup pointed out, that a coarsely tuned universe is no more probable than a finely tuned one. That is certainly not what the proponents of fine tuning want to say. Davies continues:
“This is surely a reductio ad absurdum of the whole argument. What is needed is some sort of metatheory […] that supplies a well-defined probability for any given range of parameter values. No such metatheory is available, or has to my knowledge ever been proposed.”
So, we actually cannot say that the parameters as they are today are improbable given naturalism.
Kalam Cosmological Argument
The Kalam, as defended by William Lane Craig and others, was the second potential opportunity to establish special considerations for something like the Big Bang. We didn’t get into this much, but one person on the Christian side did claim on multiple occasions that the past could not be actually infinite (part of the second premise of the Kalam). My response to this would have been too long, so I’ve saved it for the blog.
The support for the claim that the past could not have been actually infinite comes in two flavors—conceptual and scientific. I’ll cover two arguments under each heading.
Conceptual Arguments against Infinity
The first type of conceptual argument is usually an updated version of Galileo’s Paradox.
Imagine two infinite multitudes. One is the set of all numbers and the other is only the set of numbers that are squares.
C : 1, 2, 3 …
C': 1, 4, 9 …
Of course, not all numbers are squares, so it is tempting to say that there should be more numbers as a whole than numbers that are squares. Yet, these two multitudes have a 1:1 correspondence even though C’ would be a proper submultitude of C.
This is claimed by some to be a reductio of actually infinite multitudes. However, it’s not actually clear that should be our response. The problem as stated so far doesn’t contain any issue worthy of such a claim. It’s only when we bring in two assumed principles about multitudes that the reductio takes shape. These are (from Logic and Theism):
(i) There are not more things in Multitude M than in Multitude M’, if there is a 1:1 correspondence.
(ii) There are more things in M than in M’, if M’ is a proper submultitude of M.
This is important in determining the solution to the paradox because it shows you some options. You can reject one or the other or you can simply say neither of these principles of multitudes should carry over to a discussion of infinite multitudes. This was Galileo’s own solution:
“We cannot speak of infinite quantities as being the greater than or less than or equal to another.”
Galileo’s response to his own paradox was to say that we incorrectly want our assumptions about finite multitudes to carry over to infinite multitudes, but perhaps that is a mistake.
Another route would be that of Georg Cantor. His route was to hold onto (i) while restricting the condition of proper submultiplicity to finite multiples. This allows you to still compare infinite multitudes.
There are other responses, as well, but you get the idea. It is not obvious or straightforward that this is a reductio.
The second type of conceptual argument intends to convey that it is impossible to traverse an actual infinite, meaning we would never reach now from an infinite past. This may be phrased as knocking over an infinite set of dominoes, trying to fill an infinitely large hole with dirt, or trying to successively add numbers to reach infinity. People often find these examples very persuasive, but I maintain these intuition pumps are only working because they are flawed analogies. Quentin Smith pointed out several of the ways in which these are flawed in his paper Infinity and the Past. One point by Smith was the following (aleph-0 is just a way of talking about an infinite set):
“Aleph-0 events could have occurred before the present event such that no one of these events is separated by aleph-0 events.”
And you might be surprised to hear that Aquinas agreed with that assessment in his discussion of the Five Ways:
“Passage is always understood as being from term to term. Whatever bygone day we choose, from it to the present day there is a finite number of days which can be traversed.”
For further reading, you can also read two critiques by Christian philosopher Wes Morriston along similar lines here and here. Again, there isn’t an apparent problem, as far as I can tell.
Scientific Arguments against Infinity
Contrary to what some say, it is not scientifically accepted that the universe must be finite in time. For example, I emailed Caltech physicist Sean Carroll (unrelated to this post) to ask his opinion on certain aspects of the Kalam, since he is one of the leading scientists working on theories of time and is also well versed in the philosophy of time. He had this to say:
“I don’t think a lot of these concepts are very grounded in things we understand about the universe. For one thing, there’s no reason at all to doubt that actual infinities are possible.”
But we are often told the Big Bang is scientific evidence of a beginning to both space and time. Further, we are told this is what physicists believe. In my opinion, that’s problematic for at least a few reasons:
- There is no accepted theory that actually takes us back to the Big Bang itself. That’s because General Relativity breaks down on certain scales. So, the implication of our expanding universe and standard general relativity is that the observable universe was once confined to a smaller, denser, hotter space. Anything more will require argument and evidence.
- Many of those theories that actually take us to the “bang” seem to take us through the Big Bang singularity (or whatever it actually is) and onto the other side, according to the mathematics, meaning something existed prior to it (that is my interpretation of M-Theory, for example, but I welcome any correction as this is not my main area).
- As theoretical physicist Brian Greene shows in The Hidden Reality, we actually reach a “many worlds” conclusion through several independent branches. They aren’t all identical, but many of them are and they all at least point to aspects of existence beyond our perception. In other words, the multiverse is not simply an ad hoc reply to certain philosophical problems. It really is entailed in a number of ways. What matters is whether one of the theories entailing them is correct.
I believe the vast majority of physicists would take no issue with what I’ve said here and, in fact, do not currently maintain strongly that space and time began at the Big Bang. I think Craig also realizes that appeals to the Big Bang have now become problematic. That is why he now refers to the Borde-Guth-Vilenkin Theorem as evidence instead. As I understand it, the BGV Theorem is supposed to show that a first singularity is implied by the theory of inflation. Now, going down that path is going to get very complicated, very quickly. Just look over the linked paper and see if you grasp the equations. The vast majority of us do not have a sufficient background in either cosmology or mathematics to understand and evaluate the argument properly, much less its further implications. This means the apologists presenting these arguments don’t really understand them. They are simply parroting William Lane Craig. Actual physicists, like Sean Carroll, are hesitant with what we should conclude from the BGV Theorem and inflation in general, and that’s enough to know that the evidence is not rock solid proof, as Craig would have you believe. His case hides a lot of assumptions in physics and cosmology that are contentious.
So, Big Bang cosmology and the BGV Theorem do not necessarily lead us to conclude the past must have been finite.
So, I’ve covered two very popular arguments about cosmic origins and given reasons why I doubt their claims. We cannot really make a probabilistic case for fine tuning and we cannot say with any confidence scientifically or philosophically that actual infinites are impossible. If I bring it back to my initial overview, this means I’m rejecting the idea that there is cause for special consideration here (i.e., deviating from narrow naturalism).
Finally, I just wanted to mention that several times I heard the point being made that atheists are stuck with saying something must come from nothing. I want to note that I have made no such claim, which would make this a Straw Man. I lean toward an infinite past as a good option and that completely sidesteps that objection. But this brings up an interesting point. I believe Paul Draper came up with the term Fallacy of Understated Evidence, which is basically when you point out one feature of a situation that is problematic for your opponent, but ignore a feature of that same situation that is bad for you. As much as people love to say this idea about something coming from nothing, there is a problem of similar difficulty for the theist and it is one they cannot sidestep, as I have done. They have to explain why we should believe that the immaterial can affect, create, interact with, etc. the material. This goes back to the Mind-Body problem, but is really a broader problem than that. Any religious cosmology that does not address this seemingly impossible interaction will be severely lacking and I know of no good account.