Here is my comment policy, and technical help if you want to include equations in your comments:

1) You are welcome to leave comments on old posts—pretend they were all written yesterday!

If you attempt to leave a comment and for some reason it does not appear, perhaps it has gotten stuck in the spam filter.  Please send me an email letting me know and I will rectify the situation.

2) Please make some attempt to put your comment on a topically suitable top-level article, e.g. the one which you are responding to.  (If you can't find a good place, go ahead and put it somewhere random—I don't mind the occasional off-topic comment, but it's awkward if it could have been on-topic had you put it in the correct place.)

3) You can include LaTeX formulae in your comments by putting double dollar signs on either side.  For example, {\mathrm \$\$\verb|\|frac\{e\verb|^|\{-X\verb|^|2 / 2\}\}\{\verb|\|sqrt\{2\verb|\|pi\}\} \$\$ } becomes \frac{e^{-X^2 / 2}}{\sqrt{2\pi}}.  If you want to break it out into its own line, just place an "!" immediately after the first pair of dollar signs.  (Don't try to use the format, since that doesn't work on blogs)

4) Don't use the symbols < or > in your comment (unless you use just one), as WordPress may intepret them as an html tag and mutilate your comment!  You can make these symbols by inserting \lt or \gt inside of the double dollar signs, for < or > respectively.  Alternatively you can use the html escape codes \&lt; or \&gt; even outside of the double dollar signs.

5) At this time there is no way to edit your own comments to fix typos or incorrect equations.  However, if you write a second comment pointing out the mistake, I may fix your original comment and delete the correction, so that it looks like you got it right from the beginning.

6) This is a Christian website, which exists for the purpose of glorifying God.  Commenters with other beliefs are welcome to comment on the site for purposes of friendly discussion, but I ask that you refrain from gratuitious blasphemy (i.e. derogatory insults and jokes directed at God which aren't necessary in order to respectfully state your position).

However, nobody but me is obliged to follow my eccentric canonization policy of referring to all Christians as "saints".

7) I also ask that you be civil to the other commenters.

8) Commenters should provide a valid email address in the comment form, so that I can write to you privately if there is an administrative issue that shouldn't be shared with everyone.  These email addresses are not visible to the public, nor will they be released to other organizations.

The "website" field is public, but completely optional—feel free to leave it blank or to insert a link to your own website.

9) Do not simply copy and paste a large amount of text from your own pre-existing blog post into the comments section.  I will be able to tell it was not original by doing a google search.  Comments should be an individualized response to what I, or the other commenters, have said.  This does not mean that quoting relevant materials you've written before is forbidden, but it should be in the form of a link or a short quotation, and you should include an explanation of what it is, and why you are introducing it into the discussion.

10) If you figure out any other way to abuse the process, I may have to invent some ex post facto rules in a hurry.  But I would rather have a community of people who use common sense when deciding what kinds of comments are suitable.

Last updated Jun 26, 2016.

19 Responses to Comments

  1. David S. says:

    Hey. I'm a Christian and I'm very interested in apologetics. When I saw the Craig-Carroll debate, I was very concerned because Alan Guth, one of the authors of the BGV theorem, said that the universe is "very likely eternal". This would be a serious problem for the second premise of the kalam cosmological argument. It caught me off guard since Alexander Vilenkin, another author of the BGV theorem, said that Craig properly represented the implications of the theorem (that the universe had a beginning) Is the BGV theorem a reliable way of showing the universe had a beginning? Please help

  2. Aron Wall says:

    David S,
    Are you putting your trust in theorems about Nature, or the one who made Nature? If the latter, I don't see why you should be "very concerned" if the BGV theorem turns out to say less than you hoped. Of course, when we construct arguments for the Christian faith it is easy to become emotionally invested in the premises we are drawing upon, but remember that most of the saints through history found a way to believe in Christ without the aid of the BGV theorem! Apparently there are other ways of coming to know God.

    The BGV theorem very roughly tells us that inflation can't have gone on forever to the past, but it does not automatically imply that there was an absolute Beginning, as I discuss here. This was part of a longer series about the question of whether there was a beginning, according to the our current scientific knowledge.

    The fact that Vilenkin and Guth have different views from each other is a normal difference in scientific opinion, coming from the fact that our best current theories of Nature break down in the very early universe. Personally I think Vilenkin's view is better supported by the evidence, but I can't say it's been scientifically proven.

  3. Duc Phan says:

    Hey Aron,

    I tried finding your email to send a personal gratitude for the work that you have done on this blog but I wasn't able to. So I'm just going to comment it here.

    Your blog is a blessing to me. I feel that your honesty and transparency on scientific as well as theological issues really give a clear and concise explanation. And it is also a blessing to see that there are Christian who pursue the sciences and invest time to put it in layman terms for us to understand.

    Because of your blog, I now have one more venue where my faith can be strengthen. I can be assured that faith does not depends solely on personal, subjective encounter with God (and I'm not denying that this isn't an important aspect, I think it is a crucial aspect), but that there are evident that affirm these subjective experiences.

    And your blog really opens my eyes to what ministry really is. You are one of the few people that really make an impact for Christ even though you are not in a professional ministry position. That's really encouraging because your life really shows that whatever profession you find yourself in, God can use you greatly if you would allow Him to.

    Anyways, I just want to say a big thank you. Your work is greatly value (more so than I'll ever know in this life time). Much appreciation and gratitude from me and from deep down, God bless you!

  4. Aron Wall says:

    Thanks for the kind words, Duc. While I have no objection to being praised in public (vain fellow that I am) if you ever need to send me a private email the address is on my webpage, which can be found by clicking on the "webpage" tab at the bar on the top.

  5. i7sharp says:

    Dear Aron,

    I hope and pray you are doing fine.

    I will try to keep my comments short (perhaps more will come later, for what they are worth).

    In 2 Chronicles 4:5 of the KJV (King James Version), one will see "received and held three thousand baths."

    Can you comment on it - such as if you find anything significant in it?

    Thank you.


  6. Chris says:

    Hello Dr. Wall,
    First of all I love your blog and appreciate all the great content. I have recently been watching videos and reading online material about the Neo-lorentzian interpretation of relativity theory. One thing that made me think was a claim that Alain Aspect's experiments with Bell's inequalities demonstrate simultaneous causation with spatially distant photons. Just a small sample of what I have been reading (I don't expect you to read it all, I am just linking a sample of the type of material I have been reading) - I guess my question is this - Is there any principled reason to prefer the Lorentz interpretation of relativity over Einstein's? What about vice versa? Are there any experiments that cast doubt on either interpretation? I have heard that the main driving force behind Einstein's interpretation was a verificationist epistemology, but I don't know if that is actually even a problem. So long story short, I am confused and hoping someone of your expertise can tell me the long story short on which interpretation is better and why. If there is no short version, feel free to direct me toward a book or some other form of long reading.

  7. Aron Wall says:

    I think most of what I have to say about this subject can be found in these two posts.

    I don't think that Aspect's experiments on entangled particles imply simultaneous causation at all! At least, the result you get is the same regardless of which order you measure the two particles in. So it seems arbitrary to say that one is the cause and the other is the effect. It is true that the Bell Inequality tells us that the two measurements are correlated in ways that no classical pair of systems could be, absent causation. But that just means that classical mechanics is wrong, and you need quantum mechanics to describe the way in which the two particles are related.

  8. adam Sanders says:

    Hey there, this is Adam sanders. My mom (Donna Bayles now Sanders) and your dad are first cousins. You guys came to our house near mount Shasta a couple of times, and we saw each other at a couple of family reunions. I saw you like con law, which is great. I am in my last year of law school and plan to go into con law practice. Just surfing Internet and saw your pic. The last time I saw you you had just started your beard! Congrats on marrying Helen of Troy! God bless you cuz.

    Adam sanders

  9. Aron Wall says:

    Hi Adam,
    Nice to hear from you again! Yes, I remember who you are...

    Actually I don't have the beard anymore, so I should really update the picture on my website, even though it's a pretty good picture otherwise...

    Cool thing about Constitutional Law. I hope you find it stimulating! If you want to know some of my own views, you can find them here.

  10. Billy says:

    Hello professor wall,
    I have a question for you. I recently read your paper about the "GSL"pointing to a beginning of the universe. My question is since you said that the theorem would only work if the universe was infinite in size. But what would happen to the GSL if the universe was finite in size? Thank you Billy

  11. Aron Wall says:


    The GSL states that the area of any causal horizon, plus the entropy of matter outside, increases with time. A causal horizon is defined as the boundary of what some worldline can see, and you can think of it as being made of imaginary rays travelling at the speed of light.

    If the universe is finite in size, all this would still be true.

    However, in a finite sized universe, it is possible that, if we look backwards in time, the lightlike rays that make up the horizon might travel all the way around the universe and intersect themselves on the other side. If this happens, then there exists a moment of time t* before which the causal horizon no longer exists (in other words, an observer at late enough times can "see" the entire universe before time t*, using signals that go at lightspeed or slower. If this happens, then the GSL doesn't tell us anything about what happens before time t*. And therefore, you cannot use it to prove the existence of an initial singularity.
    (If you want to imagine a finite sized universe, it may be helpful to think about e.g. the spherical surface of the Earth, and pretend that the radial (up-down) dimension doesn't really exist. Only the 2 dimensions on the surface exist, and if you go far enough in these directions, you get back to where you started. However, the circumference of the sphere can get bigger or smaller with time, if the universe expands or contracts. Of course, the universe has 3 dimensions of space, not 2, so you'd really have to imagine a hypersphere BUT for everything I am telling you, visualizing a sphere is good enough!)

    One famous example of a finite sized universe in which there is no first moment of time is called "de Sitter spacetime". This looks like a sphere which contracts in size down to a minimum size, and then starts expanding forever. This example is consistent with my theorem, as well as with the classical Penrose singularity theorem, which my work is based on.

  12. Billy says:

    Hello professor, thank you for your response I have another question about quantum physics. If you have time. I heard victor stenger make an objection against the causal principle. His objection is that in physics there are certain things that don't have a cause. His examples are When an atom in an excited energy level drops to a lower level and emits a photon, a particle of light, we find no cause of that event.
    Similarly, no cause is evident in the decay of a radioactive nucleus. Is this true that these things are uncaused? And refute causality? Also I heard a claim that bells theorem refutes causality. Here is the link to the bells Theorem objection. If you have time. Thanks you for your time Billy

  13. Aron Wall says:

    Dear Billy,

    My take on this issue is in the 2nd post of my series on Fundamental Reality. Note that in the link you give, Bell's theorem is important only to establish that QM really is probabilistic. Since I agree that QM is probabilistic and still think things ought to have (probabilistic) explanations anyway, that isn't relevant to my viewpoint.

    I also discussed cosmological arguments here and here and here.

    If you have any further questions, please leave them on a post whose topic is relevant to your question. Thanks!

  14. Billy says:

    Thank you very much for your responses. You are very intelligent

  15. James says:

    Hi Aron! I love the blog. Yours is a very rare mind.

    I wondered if you could give me some direction. There seems to be a lot more talk these days about how the block universe does away with any kind of Aristotelian causation, presentism, and all theological arguments that rely on metaphysics of that kind. A particularly loud proponent of this line of argumentation runs

    I'm not even close to being a physicist and have to confess that I'm completely out of my league in answering claims like this. What would you say in response to something like this? Do you have any articles on the subject, or further reading you would recommend.

    Thank you for your time.

  16. Aron Wall says:

    Thanks James!

    I have written a number of blog posts on this issue, maybe you can start with Models and Metaphysics and the next two dozen or so posts in chronological order after that one. (In the bar just above the title to any given post, you can access the posts immediately before and after it chronologically.)

  17. Jim says:

    Hi Aron, thank you for your excellent blog.

    Are you a classical theist, as defined as someone who thinks God has the attributes of timelessness, immutability, impassibility, and simplicity? If not, how would you define yourself ?

    Side note, I want to call your attention to another physicist/theist: Nigel Cundy, who blogs at As you can tell from the link, he is a Thomist, and I take it you are not. But he would be an interesting person to have a discussion with.


  18. Aron Wall says:

    Yes, I am a classical theist. See this series.

    As for whether or not I am a Thomist, I am confused by your attempt to cast this as a boolean question. If a Thomist is somebody who agrees with everything St. Thomas Aquinas wrote, then I am not a Thomist. If a Thomist means somebody whose theological ideas have been significantly influenced by reading St. Thomas Aquinas, then I am a Thomist. In fact just yesterday I was summarizing Aquinas' theory of essence versus existence to one of my physics PhD students...

  19. Jim says:

    You're right that it's not really a yes or no question and there is no precise definition of Thomism, although one could maybe say that a Thomist is someone who holds most of the 24 thomistic theses.

    Anyway thanks for the response, and I'll be sure to check out that series.

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