Sean Carroll's The Big Picture

I recently read Sean Carroll’s The Big Picture: On the Origins of Life, Meaning, and the Universe Itself (Dutton, 2016). In my experience Carroll is unsurpassed as a popularizer of contemporary physics and this is on display in this admirable book. It differs from From Eternity to Here, which was, for the non-scientist at least, more challenging, delving more deeply into technical matters. (I imagine the same is true of his The

Particle at the End of the Universe, which I haven’t read.) As the title indicates, The Big Picture covers a great deal of territory, necessarily in less depth. (However, a marvelous appendix explains in some detail the “fundamental equation” of quantum field theory.)

Carroll is an atheist, but I find myself agreeing with most of what he has to say here, even though he takes for granted that the naturalism he propounds is at odds with theistic belief. His rejection of theism in favor of the naturalistic view of the world current science unequivocally supports appears to depend on a few dubious suppositions and inferences.

Early in the book (pp. 42ff.) he takes pains to point out that we are not justified in assuming that there must be an answer to every question we can frame. The Principle of Sufficient Reason cannot be proved; it is a useful but not a reliable guide to understanding reality. (I think the proper conclusion is that it is reliable but not, so far as we know, an infallible guide.) “We are not entitled to demand that the universe scratch our explanatory itches” (p. 45). For all we know the fundamental nature and existence of the universe is a brute fact. Lurking in the background here is the low entropy state of the observable universe, something Carroll invokes to explain various significant features of our world, but does not attempt to explain here. However, this is a question he takes up in From Eternity to Here.

However, much later in the book he says things that, if not contradicting this, stand in some tension with it. He writes, “Everything we’ve experienced about the universe suggests that it is intelligible….Mysteries abound, but there’s no reason to worry (or hope) that any of them are unsolvable” There is, he advises, no need “…to take refuge in a conviction that the universe is fundamentally inscrutable” (p. 430)…unless, one might be tempted to suggest, someone is appealing to the PSR to argue for God as the creator, in which case it must be emphasized that for all we know the universe is a brute fact for which there is no ultimate explanation. Ironically, the context for this passage is the need to seek real explanations for what we find in the world rather than calling it a mystery due to inscrutable divine action.

When, midway through the book, Carroll addresses the traditional theistic claim that the contingent universe is intelligible only if it’s the creation of a necessarily existent being, he casually dismisses it: “…God isn’t a necessary being, because there are no such things as necessary beings” (p. 203). The objects of scientific investigation are contingent, but if God exists he is not an object of scientific investigation, so he might not be contingent. (Many, both theists and non-theists, contend that if God exists, he does so as a matter of necessity.) There are philosophical objections to ascribing modal properties like necessity to things (de re) rather than just to language (de dicto) but Carroll does not refer to them. Instead, he makes the irrelevant claim that we ought not to rely on a priori principles when it comes to explaining the universe. This might, or might not, be true, but the theistic claim is offered as an explanation, and thus as a conclusion, not a premise, a priori or otherwise. The fact that the Principle of Sufficient Reason might not be true has no bearing on the fact—if it is a fact—that the best explanation of the universe involves a necessary being. (And if it is a fact, there remains the further question of whether it’s not just best but good enough to be rationally accepted.) Carroll’s question-begging rejection of the theistic conclusion is surprising in light of his commitment to the traditional distinction between necessary and contingent truths, this manifest in the course of contrasting mathematical and scientific reasoning (pp. 123ff.) One might acknowledge that there are propositions that are necessarily true but deny that any of them are existential, claims about what exists. But this may well appear arbitrary once we admit negative existential propositions, statements about necessary non-existence; some things cannot possibly exist, e.g., square circles, cats that are not animals, even primes greater than 2. Having admitted necessarily non-existent things, how plausible is an a priori denial of necessarily existent things?

Carroll poses the important question as to the likelihood of various observed features of the world on theistic, and on non-theistic, assumptions. This is one aspect of his quite charming exposition of reasoning in accord with Bayesian principles, but it is marred by the assumption that the issue is exhausted by ascertaining the likelihood of the physical features of the universe, e.g., how likely is it that God would have created a universe containing 100 billion galaxies? The exception to this is his appeal to the problem of evil: how likely is it that God would have created a universe containing it? Other kinds of evidence, particularly the historical facts that are, or ought to be, of the first importance to Christians, are ignored. Although Carroll points out that there are any number of ideas of God, his consideration of the likelihoods is adversely affected by too narrow a conception of what God’s purposes in creating might be: “Someone will argue that a universe with a hundred billion galaxies is exactly what God would naturally create, while someone else will roll their eyes and ask whether that expectation was actually put forward before we went out and discovered the galaxies in our telescopes” (p. 149).

Those of us, i.e., everyone, who assign high degrees of credence to various things are at risk of telling ourselves “just so stories” when what the evidence really calls for is the reevaluation of one’s estimate of the prior probability of cherished belief. When a hypothesis predicts a hitherto unknown phenomenon, this is more strongly confirming than when it explains something that’s already known but not yet explained. So, e.g., the fact that general relativity explained the already familiar precession of the perihelion of Mercury was not as decisive as the apparent displacement of a distant star when light from it passed near the Sun, yet it was important to general relativity’s confirmation and no one was justified in rolling his eyes at Einstein on this score. What we actually observe can make it reasonable to revise downward the prior probability of one’s theistic belief, but it can also make it reasonable to revise and/or more clearly articulate that belief. Here the crucial consideration seems to be whether we have other, independent reasons for those changes. Does a concept of God and his aims in creation that accords a high likelihood to the kind of universe we actually observe better fit the biblical account and the Church’s experience? No doubt, there’s plenty of room for self-deception here and such claims call for a strenuous defense. But I don’t imagine, for instance, that Carroll would really say that it would have been unreasonable for a Christian in the 1630’s, cognizant of Galileo’s astronomical observations, to change his mind about the likelihood of certain views of celestial bodies, at the cost of revising his presuppositions about how to interpret scripture, rather than simply finding Scripture’s reliability and ultimately God’s existence less probable in light of the new evidence. In retrospect it’s obvious that the Church in Galileo’s day relied on hermeneutical methods that are unreasonable in light of considerations independent of the discoveries of early modern science. What Galileo saw with his telescope improved our understanding of God; it did not undermine it.

It’s important to keep in view that whatever the folk-theology of “generic theism” might imply, the biblical, Judeo-Christian tradition has a particular conception of God’s aim in creating, viz., the existence of persons truly distinct from their creator yet capable of fellowship with him. What this idea of God makes likely can be quite different than what generic theistic belief makes likely, and it can be quite similar to what science reveals, including things we couldn’t imagine in earlier times, e.g., the vast age and size if the universe.

I share Carroll’s view that moral theory is the project of “systematizing and rationalizing our [moral] sentiments,” (p. 424) not of discovering an utterly objective moral truth. But agreeing with many atheists and theists, he holds that there can be an ‘absolute’ (i.e., objective) moral standard only if God exists. I don’t see how the existence of God is necessary—or sufficient—for moral truths being objective in some ultimate sense. (I believe, and assume Carroll would agree, that the truths of morality are in important senses objective, even though not finally independent of the human species. Colors make for a useful analogy: properties that thanks to natural selection we spontaneously project on objective reality, and which are not "there” independent of what humans think.)

Finally—and this might be a philosopher’s quibble—while I was on board with Carroll’s description of human persons as (weakly) emergent, and thus not fundamental components of the world but complex arrangements of things that are, I found it annoying to read that a human person is a “way of talking” about the world, since this is literally false. Human persons, as ontologically superficial as they are, are things that talk in various ways, but no one is a way of talking. But I take Carroll’s underlying claim about our place in the world to be correct. There are perspectives on reality from which humans, along with most everything we experience in daily life, are simply invisible.

These objections aside, The Big Picture is a wonderful book, beautifully written, often entertaining and even inspiring.