WLC on Time, Part 6: Did the Universe Begin?
William Lane Craig has dedicated a good portion of his career to the concept of Time. Unfortunately, he has not invested the time necessary into learning the mathematics and physics which are necessary to discuss the concept cogently. Dr. Craig is a philosopher of religion, not a philosopher of science. He is a theologian, not a scientist. So, when William Lane Craig posts a podcast to his Reasonable Faith website in which he upbraids someone who is an accomplished and well-respected scientist for that person’s understanding of science, I have to say that I am more than a bit skeptical.
In the podcast, Dr. Craig is responding to an interview of Dr. Sean Carroll, a prominent cosmologist, by Robert Kuhn for the program, Closer to Truth. If you would like to see the relevant portions of this interview, you can find them here, along with several other clips. Dr. Craig’s podcast makes specific reference to the clips entitled What would an Infinite Universe Mean? and Did the Universe Begin?, but I recommend the other clips, as well– particularly, Is Time Real?, as it is closely related to our topic at hand.
William Lane Craig has a very poor understanding of the science which he attempts to discuss, and as a result, he once again leaps to false conclusions.
Dr. Craig and co-host, Kevin Harris, begin their discussion of the interview with Dr. Carroll by highlighting the cosmologist’s answer to the question, “Did the universe have a beginning?” Carroll gave a very honest answer to this question, “We don’t know,” and then proceeded to explain why it is the case that we do not know. Dr. Craig’s assessment of Dr. Carroll’s response is as follows:
He says we don’t know if the universe had a beginning. His skepticism is based upon the fact that we don’t have a quantum theory of gravity yet to describe the earliest split second of the existence of the universe. The hope here, I think on his part, is that such a theory of gravity might enable us to save the past eternality of the universe. All the evidence that we do have points to a beginning of the universe, but the hope is that if you can find this quantum theory of gravity then that might serve to avert it.
This is a blatant mischaracterization of what Sean Carroll actually said in the interview. His skepticism is not merely “based upon the fact that we don’t have a quantum theory of gravity yet.” His skepticism is based upon the fact that the theory which predicts that the universe had a beginning falls apart when we attempt to describe that point in time, and it is therefore faulty to assume that the predictions of the theory hold even when the theory, itself, does not. This is a fairly basic point of logic: if P implies that Q is true, but P is not true, we cannot know whether Q is true or false. Dr. Craig, as a philosopher, should be well aware of this fact.
Worse than this, however, is Dr. Craig’s implication that Dr. Carroll is only holding onto his skepticism because he “hopes” that the universe is past-infinite. Craig is accusing Carroll of allowing his personal biases to cloud his scientific judgement– a rather ironic bit of projection, in my opinion. The fact of the matter is that William Lane Craig is wrong when he claims that “all the evidence that we do have points to a beginning of the universe.” As a matter of fact, “all the evidence which we do have” does nothing of the sort.
Imagine, if you will, that a zoologist is studying a certain type of mouse. This zoologist hypothesizes that all mice of this particular species are white, and predicts that the offspring of any two mice of this species will be white. He studies thousands of these mice gathered from numerous different parts of the globe, and he finds that they are all white. However, a colleague of his from New Zealand sends over a specimen of that species which is black, and notes that the species is commonly black there. Would our biologist be justified in standing by his prediction that the offspring of any two mice of this species will be white? Would William Lane Craig assert that “all the evidence which we do have” suggests that breeding two of the black mice together should yield a white mouse?
This is precisely analogous to the question of the beginning of the universe. One of the predictions of General Relativity is that our expanding universe can be traced backward through its inflation to a single point. While everything we know about the macroscopic universe tells us that General Relativity seems to hold true, we know that it seems to not hold true on quantum scales. Since tracing the expansion of the universe backwards inevitably leads to quantum scales, which we know that General Relativity does not accurately describe, what sense does it make to pretend that the predictions of General Relativity are likely to hold true on these scales?
Later in the article, Dr. Craig looks at Dr. Carroll’s characterization of the possibilities for infinite and finite universes.
Yes, he discusses in one of these clips the alternatives of the universe being infinite in time and infinite in space, or infinite in time but finite in space, or finite in time and finite in space. He dislikes the notion of the universe being finite in time and space because then, he says, we don’t have any explanation for why the universe looks so weird. I think that that is an oblique reference to the fine-tuning of the universe. Why do the fundamental constants and quantities of the universe fall into this extraordinarily narrow range of life-permitting values rather than into the much more probable range of life-prohibiting values?
I would agree that Dr. Carroll’s statement, here, is a reference to the fine-tuning problem. However, I thoroughly disagree with Dr. Craig’s characterization of the fine-tuning problem as being zoocentric. The fine-tuning problem is the question, “Why does the universe have the fundamental constants and quantities which it does?” The fact that these constants and quantities are “life-permitting” is no more relevant to the question than that they are “hurricane-permitting” or “asteroid-permitting” or “dwarf-star-permitting.” The question of fine-tuning, “Why are things as they are?,” would be just as relevant if a life-prohibiting universe was the only one which existed as it is if our universe is the only one which exists.
Craig continues in this line by saying:
That is just a philosophical prejudice against design as a best explanation for the fine-tuning of the universe… If the evidence does suggest a universe that is finite in time or space we can follow the evidence where it leads and be open to it because we don’t have a prejudice or an a priori assumption against the idea of a cosmic designer.
Reading this quote makes me wonder if Dr. Craig was actually listening to the interview which he is critiquing. Dr. Carroll was not discussing the problems and questions inherent to finite time and finite space as a means of arguing for infinite time or infinite space. Rather, Dr. Carroll was discussing the problems inherent to each of the different possibilities for the finitude of space and time. Immediately before discussing the problems with finite space and finite time, Dr. Carroll listed the problems with infinite space and infinite time.
Regardless of one’s theological leanings, the fine-tuning question remains unanswered from the point of view of cosmology. Whether one invokes a theological argument for a “cosmic designer” or not, the fact of the matter is that there is currently no evidence or theory within physics which would point to such a thing, and therefore the problems inherent to finite space and finite time from the perspective of physics remain.
After this, Dr. Craig moves on to the discussion of differing models of the universe, noting that some are past-infinite and some are past-finite. As regards past-infinite models, he says:
But what the challenge is is to show that this model provides an empirically tenable and plausible model of the actual universe that we observe. When you look at them more closely, for example as my colleague Jim Sinclair did in our article in the Blackwell Companion in which 10 out of the 17 that Carroll had on that PowerPoint slide are already discussed and shown to be untenable. Or, as Vilenkin did in his 2012 lecture, you find out that none of these scenarios provide a plausible empirically tenable mathematically consistent model for a universe without a beginning.
Dr. Craig’s implication is that there do exist scenarios which “provide a plausible empirically tenable mathematically consistent model for a universe” with a beginning. This, however, is certainly not the case. Let’s take a look at what Dr. Craig means when he says that all past-infinite models were shown to be “untenable” by Dr. Vilenkin’s 2012 lecture. As it so happens, if you are interested (and I certainly recommend it), you can view that particular lecture, here, on YouTube. In that lecture, Dr. Vilenkin references a paper which he co-authored with Arvind Borde and Alan Guth entitled, Inflationary spacetimes are not past-complete, to show that past-infinite models are “geodesically incomplete.” So, what then, does it mean for a model to be geodesically incomplete? We need to look no further than the abstract of the Borde-Guth-Vilenkin paper to find that “geodesically incomplete” means “inflationary models require physics other than inflation to describe the past boundary of the inflating region of spacetime.” That is to say, the physics of these models is incomplete. Therefore, it seems clear that by “untenable,” William Lane Craig means to say that the models are incomplete descriptions.
In that case, the models which Dr. Craig puts forward as being good examples of past-finite universe (Hartle-Hawking and Vilenkin’s own model) are similarly “untenable,” since they are also incomplete. Both of these models– and all other models which describe a past-finite universe– lack the unifying theory which bridges the gap between General Relativity and quantum mechanics. This is exactly the problem which Sean Carroll noted when he was asked “Did the universe begin?” William Lane Craig is using inconsistent language to arbitrarily declare that all past-infinite models of the universe are “untenable,” while simultaneously declaring that there are past-finite models which are “tenable.”
The hosts of the podcast then move onto a specific discussion of the Carroll-Chen model, which Dr. Carroll developed with Jennifer Chen. In this model, our universe is one of a number of baby-universes within the framework of a mother-universe. Half of those baby-universes have arrows-of-time similar to ours, while the other half have arrows-of-time which are precisely the reverse of ours. Craig says:
It is kind of like a forked universe where you have two universes emerging from a common beginning which is the point of least entropy. So even his own model (if it were empirically tenable) wouldn’t involve an eternal universe because that mirror universe is not in any sense temporally prior to the mother universe which gives rise to our baby universe.
Again, one wonders whether Craig even bothered to read the paper which he is critiquing. Carroll-Chen doesn’t propose that the mirror universe is “temporally prior to the mother universe.” It proposes that events in that mirror universe are temporally prior to events in our universe. This would most certainly involve an eternal universe. The mother universe is bi-directionally infinite in time– that is what we mean by “eternal.” This is not a matter of two roads forking in generally the same direction. What Dr. Craig is doing is somewhat akin to a man standing on the Prime Meridian and proclaiming that since “East” and “West” are only defined in relation to that point, that there is no sense in which New York is to the West of Moscow.
William Lane Craig is essentially claiming that there is no sense in which the negative numbers are “prior” to the positive numbers, because both extend infinitely about the pivot point at zero.
The concept of Time, and the discussion of that concept, is wonderfully interesting and amazingly complex. There are some philosophers and scientists who have devoted their entire careers to its discussion– one of my favorites is G.J. Whitrow, who authored a fascinating and comprehensive book entitled The Natural Philosophy of Time. William Lane Craig also finds the concept of Time to be enthralling. Unfortunately, he does not find it to be interesting enough to actually learn any of the mathematics or science necessary to discuss the subject competently– especially when his arguments rest upon the refutation of scientific and mathematical models which stand contrary to the conclusions which he prefers. Because Dr. Craig does not actually understand the science, he resorts to mischaracterizations of other people’s work in order to justify his position.
Sean Carroll was absolutely correct to note that the answer to the question “Did the universe begin?” is simply “We don’t know.” William Lane Craig is wrong to pretend that we have any evidence, at all, that the universe began to exist. He is wrong to pretend that past-finite models of the universe are somehow more complete or tenable than past-infinite models. He is wrong in his descriptions of scientific papers on cosmology. He is wrong in his characterization of Sean Carroll’s motivations.
In short, once again, William Lane Craig is wrong.
Articles in this series:
- Part 1: Introduction to Time and Relativity
- Part 2: Einstein the Verificationist
- Part 3: Bell’s Theorem and the Cosmic Microwave Background
- Part 4: General Relativity
- Part 5: The Nature of Change
- Part 6: Did the Universe Begin?