Why Is There Something, Rather Than Nothing?

A good question!

Or is it?

I’ve talked before about the issue of why the universe exists at all (1, 2), but now I’ve had the opportunity to do a relatively careful job with it, courtesy of Eleanor Knox and Alastair Wilson. They are editing an upcoming volume, the Routledge Companion to the Philosophy of Physics, and asked me to contribute a chapter on this topic. Final edits aren’t done yet, but I’ve decided to put the draft on the arxiv:

Why Is There Something, Rather Than Nothing?
Sean M. Carroll

It seems natural to ask why the universe exists at all. Modern physics suggests that the universe can exist all by itself as a self-contained system, without anything external to create or sustain it. But there might not be an absolute answer to why it exists. I argue that any attempt to account for the existence of something rather than nothing must ultimately bottom out in a set of brute facts; the universe simply is, without ultimate cause or explanation.

As you can see, my basic tack hasn’t changed: this kind of question might be the kind of thing that doesn’t have a sensible answer. In our everyday lives, it makes sense to ask “why” this or that event occurs, but such questions have answers only because they are embedded in a larger explanatory context. In particular, because the world of our everyday experience is an emergent approximation with an extremely strong arrow of time, such that we can safely associate “causes” with subsequent “effects.” The universe, considered as all of reality (i.e. let’s include the multiverse, if any), isn’t like that. The right question to ask isn’t “Why did this happen?”, but “Could this have happened in accordance with the laws of physics?” As far as the universe and our current knowledge of the laws of physics is concerned, the answer is a resounding “Yes.” The demand for something more — a reason why the universe exists at all — is a relic piece of metaphysical baggage we would be better off to discard.

This perspective gets pushback from two different sides. On the one hand we have theists, who believe that they can answer why the universe exists, and the answer is God. As we all know, this raises the question of why God exists; but aha, say the theists, that’s different, because God necessarily exists, unlike the universe which could plausibly have not. The problem with that is that nothing exists necessarily, so the move is pretty obviously a cheat. I didn’t have a lot of room in the paper to discuss this in detail (in what after all was meant as a contribution to a volume on the philosophy of physics, not the philosophy of religion), but the basic idea is there. Whether or not you want to invoke God, you will be left with certain features of reality that have to be explained by “and that’s just the way it is.” (Theism could possibly offer a better account of the nature of reality than naturalism — that’s a different question — but it doesn’t let you wiggle out of positing some brute facts about what exists.)

The other side are those scientists who think that modern physics explains why the universe exists. It doesn’t! One purported answer — “because Nothing is unstable” — was never even supposed to explain why the universe exists; it was suggested by Frank Wilczek as a way of explaining why there is more matter than antimatter. But any such line of reasoning has to start by assuming a certain set of laws of physics in the first place. Why is there even a universe that obeys those laws? This, I argue, is not a question to which science is ever going to provide a snappy and convincing answer. The right response is “that’s just the way things are.” It’s up to us as a species to cultivate the intellectual maturity to accept that some questions don’t have the kinds of answers that are designed to make us feel satisfied.

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124 Responses to Why Is There Something, Rather Than Nothing?

  1. John Eastmond says:

    One effectively requires no information to specify everything as a very small program can generate a list of all finite bit strings which can describe all finite things. Thus the prior probability of everything is one. Hence the multiverse simply exists.

  2. Ben Wortham says:

    I would not presume to debate you but I have enjoyed thinking deeply about these things over the last fifty years. I’ve decided wisdom includes accepting with humility the fact that some questions, including precious ones, will not be answered. By the way , your one of my favorite theorists. I think Kraus is too full of himself.

  3. carolus rex says:

    The existence of the universe may be explained by applying Anselm’s ontological argument to the Trump presidency.

    1. President Trump would be the greatest jobs president that God ever created.

    2. A President Trump who actually existed would be greater than one who did not exist.

    3. Therefore, it is a contradiction to suppose that President Trump could not exist.

    So the existence of the Trump presidency is a logical necessity, with the existence of God and the universe as corollaries.

  4. Cdr. Varma says:

    “Some questions don’t have the kinds of answers that are designed to make us feel satisfied”; well, the question of ‘satisfaction’ is itself one!!!

  5. KC Lee says:

    Or one could try an approach that dovetails with the Routledge Companion.

    From physics, if one accepts the argument in the Jan 20 comment in “Beyond Falsifiability” that classical physics is a subset of quantum physics, the why question becomes: How does the classically described universe emerge from a quantumly described one?

    Staying with physics, the answer is entanglement: one gets a classically described entity when one measures a quantumly described one.

    From philosophy, the above could be expressed as: relation before relata. In physics speak, entanglement exists before the entities.

    Hence, one answer, invoking both physics and philosophy, to “Why is there something rather than nothing?” could be the relationship called Entanglement.

  6. RandomPerson says:

    I think that almost anything is more ‘plausible’ than the “brute fact answer”. I am not a theist, but I think that the explanation “God is a necessary being ” is more rational than the brute fact explanation, at least for now (that may change for 10 000 years).

    Maybe the laws of physics are necessary (laws that “can generate” space/time/matter/energy out of “nothing”), maybe the universe/multiverse is necessary, perhaps some fundamental principle, or maybe it is logically impossible for there to be nothing. All of these explanations seem to me to be more rational than the brute fact.

    Your claim: “The problem with that is that nothing exists necessarily, so the move is pretty obviously a cheat”, is at very least controversial claim (and in my opinion false). I think that you should try to give arguments for this claim, because if you are correct about that (and I doubt it) then I would agree with you that the best answer to that question is a brute fact. Since, in that case, the only alternative would be “the question is invalid or meaningless”

  7. Ankit Patel says:

    If we discovered that our universe were a Simulation Wouldn’t that count as an answer to the question that adds value by reducing some of the mystery? It may not explain anything much about the patent universe but it surely would explain a lot about ours no?

  8. Ben says:

    Very interesting! Ludwig Fahrbach (2005) has an interesting paper on brute facts and how they can further our understanding of the world, which seems relevant to the topic of your chapter. https://link.springer.com/article/10.1007%2Fs11229-005-6200-7

  9. Allen Shepherd says:

    No theist comments at all!

    The universe shows amazingly carful physical constraints so that life may exist. That does not seem a chance happening, but rather an act of purpose. To ignore this is to ignore a basic reality.

    The only cause for purposeful acts that we know of is mind. The universe, at base, because of its very constrained existence, seems to indicate a mind. This is not an irrational assumption, and is based on known properties of the universe without unnecessary postulates of things that cannot be shown to exist (an unobservable multiverse).

    Theism cannot thus so easily be dismissed because of this trait of the universe, but is an inference to the best explanation.

  10. marten says:

    Why is there entropy rather than a zero entropy state.

  11. Mohammad says:

    Just because physics can not explain the “why” you are suggesting we shouldn’t ask “why”.
    This is like a history teacher who can’t explain electromagnetic waves saying don’t question and don’t belive in radio waves.

  12. Muhammad Ali Shahbaz says:

    How beautifully we escape the possibility of metaphysics. The whole history of humanity is full of a belief in God. God’s presence was felt by human beings of all ages. Man could not create a vacuum in himself by negating the existence of an absolute ultmiate reality. And now here we are trying to rob him of his satisfaction. and that too with no absolute logic!

  13. Simon W says:

    When the day comes that we can ask a very advanced general AI the question of why, it will say ‘insufficient data’. I think we should concentrate of what we can detect and measure, and just accept that answer may never come. And obviously, not make up an answer that makes us feel good (god).

  14. Alan D McIntire says:

    It just so happens that negative gravitational energy just about balances out positive kinetic energy.
    With net zero energy in the universe, the universe DOES consist of nothing- in equal positive and negative amounts.


  15. Miguel Delagos says:

    Having human minds, conditioned by the evolutionary history of our species, any postulation we derive will be confined to what the limited human brain can conjecture. We simply cannot think in non-human ways. As a part of the Universe, we do not have a privileged perspective on the whole, only a contingent perspective. The Universe may very well have a purpose and meaning (or not) but the best we can ever do is intuit at it but we can never know it. My advice: Just enjoy the ride.

  16. Ima Bezinga says:

    Why is there something rather than nothing?
    Because there must be.
    ____________ abhors a vacuum.
    (fill in your appropriate deity or idiom)

  17. Very Bertrand Russell-esque this post. He critiqued the premise that the universe is contingent many decades ago. He called the causal principle into question and found it suspect.

    Defenders of the cosmological argument contend that if the components of the universe are contingent, the universe itself is contingent. Russell replied that the move from the contingency of the components of the universe to the contingency of the universe commits the *fallacy of composition*, which mistakenly concludes that since the parts have a certain property, the whole must likewise have that property.

    Another way of articulating this objection is to say that even though causality applies to the known world, it does not necessarily apply to the universe writ large. Concisely put, it is unwise to draw conclusions from an extrapolation of causality beyond our experience.

  18. Jeff Jones says:

    This article has many flaws in logic. The God revealed in the Judeo/Christian bible reveals in pretty good detail His reason for creating the space/time ‘reality’ in which we exist. His revelation is that the Spirit realm in which He is supreme is the only reality, the physical world is a temporary construct that will disappear when His purpose is done. He discusses the physical creation and man’s puny attempts to explain Him away while know virtually nothing about which they speak in the book of Job. He supports the fact that He is not constrained by time or matter. The person of the Godhead reveled as Christ makes this very clear by claiming in both the old testament as a Spirit being and in the new testament as an incarnate being as “I Am”. Not ‘I was’, ‘I will be’. Unconstrained by time.

    If you truly call on mathematics as being the god of creation, your god is forsaking you. Any aspect of the observable world you consider is proved impossible to have occurred by chance by the god of math. Further, math proves that the physical creation came into being from nothing and will eventually cease to exist, back to nothing. I am amazed that theorists acknowledge this totally biblical construct, yet reject the ONLY revelation that accurately documents and predicts this history.

  19. William says:

    I’m with Alex Norman. Tegmark’s “Mathematical Multiverse” idea seems to be able to explain existence without external causes: Mathematics exists irrespective of any external matrix. Some mathematical objects are perfect simulations of physical universes. All you need is a perfect simulation, regardless of whether it is ever “run” (running a perfect simulaton merely allows external observers to monitor the simulation, they are irrelevant to anything “inside” the simulation). Therefore, mathematics alone (which necessarily exists) is enough to “create” our universe.

  20. Adel Sadeq says:

    Hi william,

    Dr. Tegmark’s conjecture is right, however he does not have a model of reality to confirm his conjecture, that is the bad news. The good news is that I have such a model.


    (P.S. all answers to the comments are in the questioner’s contest thread)

    also this formula comes out the model
    1/alpha= 137.0359991

    (M_p/M_e) =(3^3/2)*(1/alpha-1) -1/3 =1836.15265

  21. john zande says:

    “This is rather as if you imagine a puddle waking up one morning and thinking, ‘This is an interesting world I find myself in — an interesting hole I find myself in — fits me rather neatly, doesn’t it? In fact it fits me staggeringly well, must have been made to have me in it!'”
    -Douglas Adams

  22. Dan Steeves says:

    I find it so amusing to see how atheists are so desperate to “prove” the non-existence of a
    Creator. And the real reasons for their disbelief? First they want to be politically correct in
    this atheist world. And second they well know that if there is a God and the source of all
    life and everything that sustains life they will have to render an account and answer to Him
    for all their acts. In other words they would have to submit to his universal sovereignty.
    This is something they refuse to do. So the easy way out is to deny his existence. The bible
    book of Psalms chapter 14 states the true reasons for atheism.

  23. This is one of the enduring enigmas of both physics and philosophy. It seems deceptively deep, yet is as shallow as “why did the chicken cross the road?” It really doesn’t much matter why we should think this way and ask such silly questions, because, depending upon belief and ideology, one will get a different answer from every person, depending on that person’s nature/nurture upbringing and all of the attendant social, cultural and psychological nuances to which he/she has been exposed. Failing all of the previous (when the person has flat out rejected those influences), the answer may be radically different, or, may consist of something like: why do you ask such silly questions? In either of any cases, the outcome is of dubious value. It is not something likely to get us, say, another habitable planet.

  24. neoritter says:

    To be a little tongue in cheek, sure we probably won’t ever know, unless you die and (insert religion) is correct about the afterlife. Albeit, the one’s where you’ll be more cognizant of the situation would be more surefire on that regard, for example Christianity.

    Related to other comments, I think “why” is a completely valid question for scientists. Why do marsupials have pouches? Why do whales have comb-like teeth? Why doesn’t gold rust? I could go on with a lot of completely valid why questions that scientists could ask. Why does our universe exist? Maybe it serves a purpose in a broader multiverse (assuming the multiverse is a real thing)?
    Is it a high priority or truly important question in a non-theistic sense? Meh. But neither is the question of why dogs tend to defecate on a North-South axis.

  25. Tom aaron says:

    Its 2018. We’ve barely invented modern physics. Ask back in a thousand years when we have AI and biongineered our minds to grasp greater concepts.

    My own ‘hunch’ is that everything is some type of a simulation and quite rational and the concepts of something and nothing are human constructs to explain our limited senses. But…nobody knows.

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