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Does the Universe Need a God?

September 10, 2012

Sean Carroll has an excellent essay “Does the Universe Need God?” which appears in the collection The Blackwell Companion to Science and Christianity.

The essay argues that cosmology doesn’t require or support theological hypotheses. Sean has given permission for us to post it here to be subjected to comments. Maybe he will reply to some. As usual comments will be moderated.

8 Comments leave one →
  1. September 12, 2012 10:08 am

    Short article by Carroll, but hard-hitting nonetheless. Exploring the limits of our cosmological understandings and how those limits relate to postulates by Theistic creationists. I remember reading in Michael Martin’s tome Atheism: A Philosophical Justification that he spent a good deal of time deconstructing Swinburne’s statistical analysis.

    I did have two faults with Carroll’s paper; both anachronistic in character. On page 4 he distinguishes between the Euclidean and Lortentzian geometries. He refers to the former as four-dimensional and to that latter as a spacetime that postulated space-like and time-like properties. Technically, a Lorentzian geometry isn’t a spacetime, but a 3+1 ontology of space and time. Similarly on page 12 Carroll refers to Newtonian spacetime in contrast to general relativity. But again, Newton didn’t postulate a spacetime; like Lorentz he had 3+1 ontology of space and time.

    These are small points, but necessary. All A-theoretical Presentist’s (that I know of) fight for this distinction when relying on a Lorentzian (or, neo-Lorentzian) space and time ontology.

  2. Alison Fernandes permalink
    September 16, 2012 3:25 pm

    Thanks very much for the article, it raises some interesting points. Just a few questions:

    1) Could you explain a bit more about the apparent fine-tuning of the vacuum energy? I’m not sure I understand how it can be said to have a “natural” value, a value it should had, and that we would expect it to have, where we derive this merely using techniques of quantum field theory. What is it derived from?

    2) Without understanding this, I guess I don’t understand why some values of the parameter are easier to tune to (for nature or God) than others. There seemed to be a suggestion that the parameters might be ‘more tuned’ than they are have to be (given anthropic reasons), off by more orders of magnitude, and this implied something about the chance of finding ourselves in such a state. But don’t we need a probability metric (or a statement about God’s abilities) to make this implication work?

    3) I was also curious about why you thought anthropic reasoning could be used regarding option #3 (different parameter values in different parts of the universe) but not in option #2 (one universe with “randomly-chosen” parameters). Under option #3, it is no surprise that we find ourselves in a part of the universe where the parameters are compatible with life existing. But surely there is no surprise, under option #2 either, that the “randomly selected” parameters are compatible with life. Or is this merely what ‘playing along’ with this line of thought requires (footnote 2)?

    4) Finally, I was also wondering if you were tempted by a line that looks to the nature of explanation to dismiss some of the requests for explanation (of the existence of the universe and others)? Rather than simply refusing the requests, we can say something about what explanation is meant to achieve and how it is structured. And we can say something about why someone might be misled to request an explanation. I took that to be the point of an earlier diagnosis: that our typical practice of explaining later events in terms of earlier ones illicitly leads us to expect an explanation of the earliest event. Agreed, there will always be a point at which explanations bottom out, but we can say something to justify why such points are appropriate.

    And in this regard it also seems we can do better than merely pointing out what is surprising to us in the context of our current theories. You claim that ‘States of affairs only require an explanation if we have some contrary expectation, some reason to be surprised that they hold’. But clearly people have been surprised by things, even if they’ve grown up in a unique universe, or in the context of theories where some questions don’t inevitably arise. And it seems a positive aspect of theory change that novel explanations can be offered for phenomena a previous theory took for granted. Or perhaps I’m missing the point of this discussion (at the end of the section ‘Accounting for the World’, p. 11).

    Thanks very much.

  3. September 19, 2012 6:00 pm

    Bryant: I’m not sure what the distinctions are, beyond definitional; hopefully what I meant was always clear in my article.

    Alison: I’ll give these a shot–

    1) Field theory gives us a “reasonable” range for the vacuum energy, essentially between plus and minus the Planck density. There is no rigorous measure on this range, since we don’t have a theory of theories. But the observed number is so incredibly tiny compared to the range that most people think it’s very surprising. Of course, if there was some reason to pick a particular measure that was strongly peaked at small values, the situation would be different. For more details see:

    2) For the vacuum energy, the observed value is very close to the anthropically allowed range. For the entropy of the early universe, the observed value is enormously smaller than the anthropically allowed range. And for this latter quantity we actually do have a measure, since it’s a feature of the dynamical solution rather than a choice between competing theories. See:

    3) There are different versions of “anthropic reasoning.” If there is only one universe, it’s true that we wouldn’t be here talking about it if the parameters didn’t allow for our existence; but I’m not sure I would count that as an “explanation.” If there are many different regions with different parameters, I think it’s fair to say that the existence of this ensemble helps explain the values we observe.

    4) Probably I would agree with that, if I understand you correctly. My main point was simply to argue that we don’t get to decide ahead of time that certain features of the world “must” have deeper explanations; sometimes we are pretty sure that such explanations exist, while sometimes it’s less clear, but in every case we must be prepared to take what the universe ultimately gives us.


  4. Elliot Tarabour permalink
    September 22, 2012 4:20 pm

    There is an implicit assumption in theological reasoning that “God” is something/someone in the past that “created” our universe/multiverse. What if “God” is a future state that may be a possible/probable/unavoidable outcome of our existence? This is certainly less amenable to experimental proof/disproof but is a different way of viewing things. It may be suggest that the universe is “purposeful”. (word used very loosely)

  5. October 13, 2012 3:15 pm

    Sean Carroll’s wonderful article provides an excellent perspective on possible roles of God in creating or maintaining the universe. However, there is an interesting line of thought omitted in the article that can perhaps be best introduced by adding a 5th option to the list provided by Carroll to account for the apparent fine-tunings that we find in our universe. This additional option is best understood in terms of the relational interpretation of quantum mechanics (RQM) as discussed by Rovelli et al in the past two decades. RQM assumes that all systems are quantum mechanical (with no observer – observed distinction) and that the state of a system is never objective, but can only be defined relative to other systems (thus abandoning the concept of strict Einstein realism). And yet the resulting description of reality is found to be internally consistent and complete. This interpretation has been highly successful in addressing otherwise puzzling ambiguities of the “measurement” problem, and also resolves the EPR paradox in a way that does not require any elements of “non-locality”.

    A corollary of the RQM assumptions is that there is no meaning to the state of the entire universe, since there are by definition no systems outside the universe relative to which such a state can be defined. Thus, suppose one postulates a reality underlying the phenomena that we observe in our universe consisting of more fundamental elements which do not in themselves include the specific properties that we find associated with the constituents of our universe, such as unique values of fundamental constants, the existence of particular particles and their fields, and even the spatial and temporal relationships between events. (Penrose’s postulated “twister” objects have some of this flavor.) We imagine that these fundamental elements can, however, produce particles and fields corresponding to various values of fundamental constants and allow them to be arranged in various space-time metrical relationships. Furthermore, there is no reason to expect there to be a limit to the number of ways that the same underlying elements can be arranged so as to produce other observed universes totally different from ours. Note that these various universes would not be related spatially or temporally to each other, as in other multiple-universe concepts, but would instead be analogous to different projections of the underlying reality onto the space of all possible values of fundamental constants, space-time metrics, etc.

    In the case of “our” observed universe, “we” are each an RQM system observing the remainder of that universe, and the state of this complementary RQM system must be defined relative to each of “us”. Thus, it is inevitable that the properties of this observed complementary portion of the universe is consistent with “our” own existence. Here of course, words like “we”, “our”, etc. are to be taken in a totally non-anthropocentric sense, instead including not only all forms of life that exist and have existed previously on Earth, but also perhaps elsewhere in our observed universe, in places where life can exist under the corresponding conditions. (This possibility is to some extent supported by the observation in space of organic compounds similar to those that form the basis for life on Earth.) The added option in Carroll’s list might thus be stated as:

    5. Since the state of any part of a universe is defined only with respect to systems not included in that part, our universe, which contains living systems, must have a fine-tuned state consistent with the existence of these living systems.

    Of course, this still does not exclude a role for God in the creation of the postulated underlying reality, and we have no view on this question.

  6. October 16, 2012 8:58 pm

    A few points in my comment would benefit from additional emphasis or elaboration. The state of a quantum mechanical system represents a complete description of the system, and thus totally represents reality with regard to that system. In the assumption in RQM that the state of a such a system is defined only with respect to other systems, RQM is denying the objective reality of all systems, since all systems within the universe are taken to be quantum mechanical. This leaves open the question of whether the postulated underlying elements are also quantum mechanical in nature. Here, the answer to this question is assumed to be in the negative, and these elements are taken to constitute the objective reality underlying the universes formed out of them. We imagine that the unavoidable statistical uncertainties associated with typical quantum mechanical states are a consequence of the inherent limitations of the projection-like process through which a given universe is created from the underlying reality.

    It may seem strange to contemplate that our universe does not have an objective reality, but only a subjective one (i.e., RQM system state) relative to “us”. (Again, recall the generality of “us” in this context.) Our world, including ourselves, seems very real to us, frequently exhibiting more or less solid objects of a persistent nature. Of course, advances in science theory and experiment have not supported this intuitive view. The apparent objects in our universe are almost all empty space, with the balance in a state of constant change. Smolin has expressed this well by asserting that “there are no things, only processes that appear to change slowly on our human timescales.” And these processes are just the time evolution of RQM systems completely specified by their states relative to other systems in the universe.

    Since our universe, according to our added option 5, must have a fine-tuned state consistent with the existence of its living systems, can it be said that “we” have created this particular universe? Living things persist by frequently modifying themselves as well as by affecting other systems in their neighborhood, resulting both in changes in their own state as well as the state of the complementary universe. So “we” individually modify our universe in at least minor ways. But theory suggests that our universe existed before its first forms of life could have appeared so, unless we care to consider a form of backward causation, assertions beyond that would seem to be a stretch.

  7. Kevin V permalink
    November 9, 2012 5:59 pm


    I have heard some philosophers say that if a B-theory of time is correct, then the universe would have to be past eternal (and hence not need God). That is, any scientific model of the universe that postulated an absolute origin of time, space, matter, and energy would in fact have to kowtow to the metaphysical implications of a B-theory. This sounds wrong to me because even though all events are equally real and static (future eternal) in the universe on a B-theory, that doesn’t necessitate the claim that the entire ‘block’ did not have an absolute beginning of time. This sounds kinda crazy actually because it would mean that something like the Borde-Guth-Vilenkin theorem could be overturned by a B-theory of time?! Perhaps I am wrong though; I would really appreciate some clarity on this issue.

    Thank you,

  8. November 27, 2012 2:08 pm

    A very clear and well-expressed article. A minor point would be that the statement ‘Edwin Hubble and Milton Humason announced in 1929 that the universe is expanding’ is historically incorrect. Neither of them accepted the relativistic explanation for the velocity/distance relation of the spirals, then or in later years.
    A minor point perhaps, but it is illustrative of the interesting fact that science does not speak with one voice, and that explanations vary over time.

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