Rosenberg’s Atheist’s Guide to Reality Chapter 10

Chapter 10

If, as a materialist might reasonably believe, a brain is a mind in virtue of the structure of its neuronal interconnections, and a mind is the mind of a particular person for the same reason, then one need not suppose the Freaky Friday scenario presupposes that the mind is an immaterial substance. We leave the two bodies and their brains in place, but we re-organize the neural interconnections in the brains, so each realizes the computational state the other initially realized. It’s possible that the truth is more complex than a straightforward computationalism, and that whether a brain is the brain of a particular person is not settled at so abstract a level, but depends also on features that some other brain might be incapable if instantiating. In that case, persons are tied to particular brains in ways that makes the body switching scenario impossible. And of course one might contend-implausibly, I think-that sameness of mind does not suffice for personal identity and what we have here is not a body swap, but two persons becoming very confused and losing their memories.

The fact that a human person, a self, persists through all the changes in our body over the course of our lives hardly implies that it is an immaterial thing. If it did, the implication is either that the car I have today is not the one I bought in 1988 or that it has an immaterial component. But no: it’s the same car even though quite a few parts have come and gone. This does not mean that a person survives all possible changes to a body over time.  Whether a person at one time is the same person at another time depends on what kinds of changes the body has undergone: a person survives some changes and not others.

Alex Rosenberg’s An Atheist’s Guide to Reality Chapter 9

There is no question but that particular goings on in the frog brain play an indispensable role in explaining how frogs catch flies. If there were something in there that had what is for Rosenberg the magical property of being about flies, it would be of explanatory interest only if it played the causal role that the neural state in question plays, i.e., if it typically made its appearance only when a frog is in the vicinity and typically caused frog-catching behavior. Granting that nothing in the frog has the mysterious aboutness Rosenberg rejects, the temptation to point to the neural state that plays this causal role and say this is what aboutness really is is hard to resist. The Rosenbergian claim that it cannot be about anything falls flat absent some account of what it lacks that’s essential to really being about something.

Is there much of anything to the folk-concept of aboutness for science to subvert?  In my experience, if someone is asked, “What makes the frog’s idea of the fly an idea, and what makes it an idea of a fly?” the notion that it has to with some sort of resemblance of the mental item to what it represents falls apart quickly, leaving not much of anything that we are entitled to say no mere brain stuff can satisfy.

It’s interesting to ask what could be going on when someone mistakenly believes that something is about something.  Someone sees a combination of letters and in error takes it to be a word in a foreign language when in fact it’s just a meaningless combination of letters. Is it conceivable that we are systematically wrong in such judgments, or are errors of this kind parasitic on a background of correct judgments? Or one could encounter a description that fails to refer, e.g., when the student refers to Martin Luther, the German king who was an activist for civil rights for black Protestants in the 1960’s.

The crucial fact lurking here is that nothing in nature fixes reference. There is, perhaps, no objective matter of fact as to what the frog’s brain represents when it catches flies. The frog can be fooled, capturing BB’s as though they were flies, so do the goings on in its brain mean small black thing rather than fly? In some quarters much has been made of the indeterminateness of translation and the inscrutability of reference. This tells us something important about the place of meaning in the natural order, but the conclusion that what it tells us is that there is no place for it, i.e., that nothing is about anything, is hard to believe, or even grasp. I’m no fan of facile objections that charge a view with self-referential incoherence, but it’s hard not to want to ask Rosenberg if the words in his book are about anything, whether reading it doesn’t cause us to think about frogs, and so on. Physics fixes all the facts, and facts about meaning are not facts of physics. But why say this implies there are no facts about meaning? As a scientific naturalist, I want to say that we need to identify neural states as representing things in order to explain the behavior of organisms. (Not to say that there must be a local mapping of the intentional onto the neural, an identification of something in the brain as the representation of something; the brain might be in the state of representing something in virtue of rather global features, on analogy with non-symbolic, parallel computation.) The fact that there is an alternate, lower level, description, couched solely in terms of physics, does not imply that the intentional description is scientifically dispensable.

Sometimes The Atheist’s Guide reminds me of early 20th-century popularizers of science, informing us that there are no solid objects, since what we take to be solid objects are mostly empty space containing atomic nuclei surrounded by mostly empty space.  But such a claim strikes us (or at least me) as anachronistic. Of course solid objects exist, and it’s often important to distinguish them from objects that are not so solid, or not objects at all but volumes of liquid or gas. Physics reveals not that there are no solid objects but what solid objects are really like. As Wilfrid Sellars famously said, the task of philosophy is to figure out how the manifest image, i.e., the world as humans experience it fits together with the scientific image.  Sometimes this means dismissing something as illusory, a mere artifact of how we represent things, but sometimes it means revising concepts to fit into the world where physics fixes the facts.  Recall the issue that led Rosenberg to moral nihilism: our natural concept of a moral fact is of a state of affairs that provides those who detect it with a reason to act. If, as physicalists and naturalists tend to think, there can be no such practical reasons, because all reasons to act are rooted in the agent, not in objective reality, then either moral facts need not have this feature, or there are no moral facts and no moral truth.

Or consider our concept of time.  Late in his career Gödel showed that there are physically possible universes in which solutions to the equations of general relativity imply that there are closed, finite time-like loops, which is to say that in those worlds time travel is possible. He saw this result not as implying that time-travel is possible, but that general relativity reveals that what we think of as time is not captured by the fourth, time-like, spatial dimension, and thus that what we think of as time has no objective reality. Talk of time as a fourth spatial dimension is not just a way to interpret general relativity, but the sober truth: there is no such thing as time. Did Gödel draw the right conclusion? Or is the implication that time is real yet quite different than we imagined?

Rosenberg stresses the implausibility of mapping propositional attitudes onto the brain’s physical structure, and the correlative implausibility of its computation being  linguiform, or symbolic at all. On the most likely account the brain’s computation is at bottom parallel and non-symbolic, not serial and symbolic. We still need to explain human linguistic competence, the fact, e.g., that anyone who makes sense of, “The dog bit the boy” can makes sense of, “The boy bit the dog,” and it’s at least not obvious how to do so unless some serial computation goes on in one’s head. (In principle a virtual serial machine can run on a parallel machine and a virtual parallel machine can run on a serial machine.) We may have good reasons to reject the idea that in general the computation that makes a brain a mind involves propositional representations of the world, and to reject the idea that mental representations can be identified, even token-wise, with discrete brain events. But there is no reason to think the scientific explanation of human beings can get by without identifying some state of the brain as a representation, as being about goings on in the world outside the brain, even if that information bearing state consists of an activation pattern realized in some ensemble consisting of some very large number of neurons. (The Churchlands make this sort of thing sound very plausible.)

A general question that arises here is how what looks a lot like some version of eliminativism coheres with Rosenberg’s scientism. It’s hard to see how these claims cohere:

(i) Physics fixes all the facts

(ii) Physics fixes all the facts about human beings

(iii) Insofar as human beings as such are subject to scientific explanation it is by means of subsuming them under biological concepts

(iv) Biological concepts cannot be reduced to those pf physics

(v) What cannot be reduced to physics is not real; it’s at best an illusion provided by natural selection

(vi) Science alone provides the sober truth about human beings.

The only way I can make out a coherent view is by rejecting (iv) and claiming that there is an intertheoretic reduction of biology to physics.  One the one hand, it might be that natural selection can be understood as a law of physics, though it seems to me that this is arbitrary, in contrast to regarding it not as a law of nature but as an abstract principle true of anything, irrespective of its physical constitution, of which a few things are true, e.g., it makes imperfect copies of itself, properties of the copies have a bearing on the odds of their making more copies, etc.  But even if we can include natural selection as part of physics, biological explanation relies on many other concepts and some of these, e.g., gene, seem obviously irreducible to physics in virtue of being functionally defined. Further, if the scientific understanding of minds proceeds largely in computational terms, then while the facts about the mind are fixed by physics, their explanation depends on concepts that cannot be reduced to those of physics. The God Rosenberg finds obviously non-existent could make sense of the world using only the concepts of physics, but probably no finite mind, and certainly no human mind, could do so. We need the special sciences, and probably quite a few other things, even some chastened folk-psychology and history.

Misguiding Atheists

Richard Dawkins, and some others who see Christian faith and science in intractable conflict, take it for granted that the fundamentalist interpretation of the Bible is the correct one, and that when biblical scholars advise us to read Scripture in ways that do not make it at odds with science, e.g., they tell us not to think the Bible teaches that there was a literal Adam, Eve, talking snake, magical trees, etc., all on a flat Earth under the turning metal dome of heaven, this is a dishonest dodge to avoid the plain implication that the Bible teaches these things and is wrong.  It seems to me that Rosenberg adopts an analogous, and no less hard to justify, position on our common sense concepts. Whatever the man in the street, untainted by philosophy, believes about the nature of freedom, consciousness, meaning, purpose, moral truth, and so on, is correct, and any naturalistic philosophers who try to explain how these things can, with some conceptual re-engineering, find their place in the world science describes, engage in a bad-faith effort to avoid the obvious unsettling news. Rosenberg’s account leaves the uninformed reader, whether atheist, agnostic, or theist, who accepts the idea that physics fixes all the facts about this world ,with the impression that if any such project exists, it is a marginal and futile effort, not the mainstream of contemporary philosophy.

Rosenberg’s Atheist’s Guide to Reality V Chapters 7 & 8

There doesn’t seem to be much to say about Chapter 7.  Taking heed of scientific knowledge of the human mind/brain, including what it reveals about the fallibility of introspection, does significantly reshape our image of what we are. (I find the degree to which our minds are modularized and its modules encapsulated the more radical discovery.)  But Rosenberg’s quick move from the fact that introspection is not infallible to the conclusion that it is not reliable is a bit much.  Even when an apparent way of knowing fails in some dramatic way, as in the case of blindsight, this does not justify the inference to unreliability. “If it can fail in this way then it must be overall unreliable!”  Reliable ways of knowing may come up against unexpected limits. By analogy: it was extremely surprising news when Russell in 1902 wrote to tell Frege that the set theory in which he sought to ground mathematics is inconsistent, or 30 years later when Gödel proved that any formalization of arithmetic is incomplete.  That whatever cognitive mechanism underlies mathematical intuition is not infallible is a conclusion in some ways as surprising as the discovery that introspection can fail in spectacular ways.  But no one draws from this the conclusion that it is not a reliable means to obtain knowledge. Nor, when it comes to it, does the fact that we are subject to visual illusions–ones that persist when we know they are illusions, a manifestation of perceptual encapsulation–imply that vision is not a reliable way to know.

Chapter 8 is a different story:

Of course: no physical thing inherently means (represents, is about, etc.) anything, i.e., it’s not about anything in virtue of its intrinsic physical features. From this truism Rosenberg infers that no physical thing is about anything. He is entitled to this inference only if it is also true that if a physical thing is about something, then it is in virtue of its intrinsic physical features. A physical thing also has non-intrinsic properties, its various relations to other things.  Among these are causal relations.  It exists as an effect of other things, and other things exist as its effects. In a particular setting it plays a characteristic causal role: it has typical causes and effects. These causal relations are, of course, manifestations of the laws of physics recruited by natural selection in the construction of brains that navigate organisms through their natural and social environments. There is, say, a neural state typically caused by there being a cat in the vicinity, and this state in turn has, in conjunction with other mental states, typical effects. There is a mental state in Karen caused by the cat being on the table, via her visual system, and this state, together with Karen’s desire for the cat not to be on the table, causes the behavior that consists in Karen evicting the cat from its illicit location. Whatever plays this causal role in the economy of the nervous system, irrespective of its physical constitution, is a representation of the cat. This is how mere physical things can be about things.

What seems very tendentious is the claim that this is not an account of how neuronal things can be about things, but the revelation that they are not about anything. A familiar pattern: start with a folk-concept of something, show that nothing in the world where physics fixes all the facts perfectly answers to it, and announce that nothing answers to it. The alternative, that we have discovered that the concept needs revision, remains out of sight. The reiterated assertion that nothing in the brain can be about anything invites us to wonder what is being denied. The causal role theorist claims that chunks of grey stuff are about something, but that this is not in virtue of their intrinsic properties, Rosenberg says, “That’s not genuine aboutness!” But why isn’t it? What is it that those clumps of grey matter lack that precludes them being about anything? We’re entitled to ask Rosenberg to complete the sentence, “A chunk of grey stuff would be about something if_______.” Is there no way to finish the sentence because what’s required is some non-physical property? I suppose that he would regard it as equally obvious that if there were a non-physical thing, it could not be about anything either. So is it that there’s no way to complete the sentence because the concept of aboutness is incoherent; nothing can be about anything just as nothing can be a square circle? But then there’s a burden to reveal the contradiction allegedly implicit in, “That clump of neurons is about Paris.” There’s no sign of this burden being discharged.

If there’s an argument lurking here, I imagine that it’s something like:

Aboutness must be either intrinsic or derived.

Nothing possesses intrinsic aboutness.

Something possesses derived aboutness only if something else possesses intrinsic aboutness.

Therefore: Nothing possesses aboutness.

There is, I suppose, some intuitive appeal to the third premise. But is it really true? The idea is something like: the word “cat” is about cats, but not in virtue of any intrinsic characteristic; its aboutness derives from human beings, who establish the convention that makes it about what the idea cat in their minds is about, and that is about cats not derivatively but intrinsically. But then we’re left with the truistic: nothing is about something by convention unless something else is about something not by convention. Clumps of grey matter in the brain, like the word “cat,” lack intrinsic aboutness, but this does not imply that any aboutness they could have must be conventional. It might simply be natural, having its antecedents in neural structures like those of the sea slug, in which there is no good candidate for being a mental representation. Between the sea slug and humans there need be no sharp phylogenic line where aboutness appears. Eventually, though, we can economically explain a creature’s behavior only by describing some of its neural structures as representations. That which is about something arises gradually from what is not about anything; in this sense, its aboutness is derived, but not from something that has intrinsic aboutness.

This said, it might be that the upshot of all this is that we’ve found that the concept aboutness (intentionality, representation, meaning, etc.) is useless; on analogy, we’ve come around to the view that the concept witch has no application in the real world. But this strikes me as implausible. Representation, e.g., seems to me precisely how we want to describe that mental state in the mind of Karen caused by the cat and causing her cat controlling behavior.

Blogging Rosenberg’s Atheist’s Guide to Reality IV (Ch 6)

1. Whatever experiments such as Libet’s imply about free will or its lack is indirect. At face value, what they support is some kind of epiphenomenalism, i.e., that conscious states, at least the introspected experience of making a choice, don’t have the causal powers we are apt to ascribe to them. Thoroughgoing epiphenomenalism is, I assume, incoherent: if these states of what we call consciousness exist, then they do have effects, at least our reports of them. But it is surprising if, as the evidence suggests, one’s conscious choice to perform an action is not its cause, but also an effect of whatever unconscious brain event causes it. Libet’s results undermine a particular conception of free will, one on which a choice is free only if (a) it is the effect of a conscious act of will, and (b) that conscious act of will is not the effect of some antecedent event. Which is to say it subverts a robust libertarian idea of freedom. (Maybe it is an effect of the person that chooses, in contrast to some event in her, but no one has any idea how we could manifest such “agent causation.” And we really have no idea how a material being could be an agent cause, even if we believe that God is free in this radical sense.) Materialists either accept this libertarian idea of free choice but say that we do not have it, or reject libertarianism in favor of a compatibilist conception of freedom: choices are free so long as they have the right kind of causal history, i.e., they deny condition (a). However, compatibilists have traditionally accepted condition (b), assuming that the proximate cause of a free act is a conscious choice to do it, one which is a free choice in virtue of having causes of the right kind. This is typically spelled out in terms of practical rationality: a choice is free just if it is caused by the chooser’s very own, reflectively examined reasons, i.e., her desires and beliefs. Can compatibilism survive the demotion of conscious acts of choice to a semi-epiphenomenal status?

2. I don’t find this a threat to compatibilism. First, we all know that the standard account on which something or other causes one to have various desires and beliefs, these cause a conscious act of choice, and that in turn causes the bodily motion that constitutes the action, is an idealization. Most of our free and responsible behavior proceeds without conscious deliberation and choice. Libet’s experiments bring into focus what we are already introspectively aware of: Conscious deliberation is relatively rare; mostly, we just do things, without consciously examining reasons. The essential compatibilist claim is that our free choices are caused by our reasons, and compatibilism has no interest in denying the obvious fact that we are only episodically conscious of them. At this moment you have a great many beliefs and desires but almost all of these mental states are dispositional, not occurrent.

3. There is a familiar worry that our conscious awareness of the reasons for which we act need not be entirely accurate, and we act for reasons other than the ones we think we act for. This is plausible enough to have kept psychoanalysis in business for years. Compatibilism is not committed to any given free choice being an effect of conscious deliberation, but it is in general committed to the idea that a high degree of freedom and responsibility does depend on a disposition to conscious deliberation under certain conditions, e.g., when the best course of action is not obvious but getting it right matters. This is, I assume, arises from the connection of self-consciousness to personhood, and of personhood to moral responsibility.

4. It might be that our concept of freedom is incoherent, that it combines the idea of free choice as uncaused and as having causes of the right sort. (There are empirical studies that support this.) If so, we may ask just what science leaves us and whether what’s left is worth having. Is it a sufficiently robust idea of freedom and responsibility to sustain the practices where we put it to use? As I noted earlier, when we discover that something lacks a feature we’ve long regarded as essential to it, we must either continue to regard it as essential and conclude that there is nothing to which the concept applies, or revise it, acknowledging that it was a mistake to take that feature of essential. Science sometimes shows us that things do not exist, e.g., witches, caloric, phlogiston, and sometimes that what exists is radically different than we thought, e.g., atoms, gravity, the mind. Rosenberg, for reasons not fully clear to me, seems strongly inclined to elimination over revision.

5. With many philosophical naturalists, I think a good case can be made for compatibilism, but difficulties lie ahead. One worry, which I suspect figures in Rosenberg’s rejection of it, is due to the fact that at face value it depends on the idea that human behavior generally can be explained as the effect of reasons, of beliefs and desires. Explaining, and predicting, and making sense of what human beings−others and ourselves−do by appeal to these mental states manifests our innate folk psychology, a presumed product of natural selection. Suppose, as may well be true, that folk psychological concepts cannot be smoothly mapped onto the physical, or even information-theoretic, structures of the human brain. These mental things can be identified with nothing in the domain of neuroscience. In what sense can beliefs, desires, and other intentional states be said really to exist? (“Intentional” here in the sense of having semantic properties, being about something.) When kinds of thing that we want to invoke in causal explanations cannot be reduced to the things physics refers to, the status of those explanations can be problematic. Is there are place for these mental states in the objective, physical universe, and if there is, is it a place that affords them a role in causal explanation? (It’s worth recalling that it’s not reduction, but reduction’s failure, that raises doubts about the reality of things. It’s the irreducibility of mind to matter that challenges the materialist.)

6. The other worry arises only for theists. Even if compatibilism is in general true−there’s no insurmountable conceptual difficulty in human action being at once caused and free−free choice might still be impossible if God is the First Cause. After all, if God created the universe, i.e., he brought about its initial conditions ex nihilo, and authored its causal laws, then his free creative act is the remote cause of every human action. Even if our actions could be free and responsible despite being the effects of natural causes, if what one does is caused by, foreknown by, and intended by someone else, then we are not free and responsible. If you choose and act as you do as result of the microchip a clever neuroscientist surreptitiously implanted in your brain last year, then you are not free and responsible. It will seem to you that you satisfy the compatibilist conditions for freedom, but this will be an illusion. Whatever investment a theist has in free will and moral responsibility as such−maybe not all that much−a Christian theist has a profound investment in human beings being capable of relating to God interpersonally and this requires that vis-à-vis him we be free, that what we do is distinct from what he does, and that we can do other than what he wants us to do. We might be free even if everything we do is causally determined, but not if it is causally determined by God. For this reason, the Christian hopes that nature’s fundamental laws are indeterministic. If they are, then God remains the most remote cause of all our actions, but he does not specifically foreknow or intend them. So long as the creation is indeterministic God and creatures can share responsibility for what creatures do, a view that lies at the heart of the Christian faith, which confesses the crucified God who takes responsibility for his wayward and ruined creatures. Whether nature’s laws are deterministic or indeterministic makes no difference so far as the issue of compatibilism goes, but it matters a great deal when our aim is to integrate a naturalistic account of the human condition into the Christian faith.

Blogging Rosenberg’s Atheist’s Guide to Realty III (Ch 5)

1. Why should the fact that physics fixes all the facts make it hard to find room for moral facts?  If physics fixes all the facts, then if world B is a microphysical duplicate of world A, then A and B are duplicates with respect to all the facts, including the moral ones, if there are any. Physics fixing all the facts implies that any non-physics facts must at least supervene on the physical facts, which is to say that things cannot differ in any way without differing physically. So situation x cannot differ morally from situation y unless there are physical differences between x and y.  This is innocuous and tells us nothing about what kinds of facts there are. Rosenberg here seems to treat the claim that physics fixes all the facts as though it were the much stronger claim that all the facts are facts of physics. If all the facts are physical facts then it’s hard, in fact impossible, to find room for moral facts, since no moral facts are physical facts.

2. Nihilism, I take it, is the view that there are no moral facts: no moral statement is true, e.g., it is not true that one ought not to eat babies. This is no more true than the claim that one ought to eat babies. (I’m assuming that there being a fact that P is the same as it being true that P.) There just isn’t anything that morally one ought, or ought not, to do.  If nihilism is true, it’s not because physics fixes all the facts.

3. The no coincidence argument:

As a result of natural selection humans are innately disposed to believe certain things.  It would be wildly coincidental if these beliefs were true independent of this evolutionary history.  If moral beliefs are true, then they are true of reality, independent of our evolutionary history.  Our moral beliefs are products of our evolutionary history. Therefore, nihilism is true: there are no true moral beliefs.

If this reasoning were sound, it would justify many kinds of nihilism, e.g., humans are innately disposed to believe that dogs give birth to dogs and cats give birth to cats, and not the other way round. Yet it is true that dogs give birth to dogs and false that cats give birth to dogs.  This is true independent of our evolutionary history.  Sometimes the best explanation of why we have been selected to believe certain things is because they are true, and true beliefs about some matters enhance fitness.  The fact that we were naturally selected to believe that there are things we ought to do, or not do, irrespective of our desires, supports nihilism only if there can be no such facts in a world where all facts are fixed by physics. If we can’t reasonably believe that natural selection has endowed us with some capacity to know the world then total skepticism is inescapable and we are no more justified in believing the well-confirmed theories of science than anything else. The Neurathian boat in which natural selection has launched us might be pretty leaky, but we have to think it keeps us afloat! (“We are like sailors who on the open sea must reconstruct their ship but are never able to start afresh from the bottom. Where a beam is taken away a new one must at once be put there, and for this the rest of the ship is used as support. In this way, by using the old beams and driftwood the ship can be shaped entirely anew, but only by gradual reconstruction.” Otto Neurath, 1882-1945)

4. However, there is a good reason to doubt that there are such facts because, as Rosenberg says, that they all rely on false presuppositions.  If it is true that someone ought to do x, then he has good reasons to do x. (On one account, this is what is means to say that he ought to do it.) However, any reason he has to do something is rooted in his desires. No practical reasons are grounded in objective reality; the fact that such and such is true of the world in itself creates no reason to do one thing or another. That fact must connect to what one wants. Natural selection has installed in us the illusion that certain objective facts constitute reasons to behave in certain ways, particularly when we have competing reasons not to do so. This internalized constraint on self-interest is the “aim” of human moral psychology.  Objective reality has nothing to say about what one ought to do, but human minds, adapted to social life where constraints on self-interest promotes inclusive−but not necessarily individual−fitness, project the moral ought onto the world. Evolution has equipped us with the disposition to categorize social reality in moral ways, e.g., to identify some acts as unjust.  And that judgment generates the conviction that we ought to do something about it, the feeling that one has a reason to do something about the act just because it is unjust. The presupposition of all moral claims, that there are reasons to act “out there” in reality, is false.  For some, this suffices for the conclusion that all moral claims are false, i.e., nihilism.  This conclusion is sometimes called fictionalism, and its adherents often contend that while morality is a fiction, a kind of illusion, it is a useful one.  If so, then what we want gives us good reasons to act as though we believe that there are reasons to act independent of anything we want.

5. However, we must accept fictionalism only if belief in moral facts cannot survive the realization that there are no practical reasons built into the fabric of reality. Our longstanding concept of moral fact includes the idea of an objective state of affairs that presents us with reasons to act. Nothing actually falls under this concept so either there are no moral facts, and the concept should be abandoned, or our concept of moral facts must be revised. This is an instance of an important question that arises often in the attempt to find a place for what’s important to humans in the world science portrays: when have we discovered that things of a kind do not exist, since nothing has property F, which we have always regarded as essential to being a thing of this kind, and when have we discovered that we were wrong to believe that things of this kind must have property F? The answer is not always obvious. Perhaps we can reasonably continue to believe that there are moral facts even as we abandon the illusion that they impose upon us reasons for action that are ultimately independent of our desires. (Across the board, Rosenberg seems strongly drawn toward abandoning, rather than revising, our concepts. Thus, e.g., not, “We’ve found out that our behavior is causally determined, so we were wrong to assume that no determined behavior is free,” but, “We’ve found out that our behavior is causally determined, so we are not free.”)

My inclination is to reject moral nihilism, and to assert that there are moral facts but that they provide us with reasons to act independent of our desires is an illusion courtesy of natural selection. I’d say that what all this amounts to is the discovery that the moral truth is relative to the human species, not to there being no moral truth. It puts morality in its natural, human place, deflating its pretensions to transcendence. But whether the Christian can reasonably welcome this kind of relativism (or Rosenberg’s nihilism), or reasonably hope to avoid it, is a question that deserves a fuller answer.

Rosenberg’s approach is to accept moral nihilism, because there are no moral facts that provide us with reasons to act independent of our desires; that’s an illusion courtesy of natural selection.

Either way, I think Rosenberg is right to say that all this has no serious deleterious effect on moral motivation; that “nice nihilism” is the likely and reasonable response. We may note that the analogous realization that disgustingness is not a feature of objective reality, but the projection of a response natural selection has programmed us to have back onto the world, is not likely to move us to eat things that disgust us.

An aside on The Atheist’s Guide to Reality

Naturalism and the Christian Faith

Rosenberg makes scientism the defining feature of naturalism. (I tend to agree, though I prefer to conjoin what he calls scientism with two substantive scientific claims about human beings: we are material beings, the product of blind natural selection, and to call this scientific naturalism. What Rosenberg refers to as scientism I think of as the epistemological preeminence of science, and I’d use the term “scientism” to denote the claim that scientific knowledge is the only knowledge. But this is just terminology; nothing important turns on it.)

Scientism (as Rosenberg deploys the term) then, is the claim that science is our best way of knowing in the sense that (1) Any other claim to know should be rejected if it is logically inconsistent with the well-confirmed theories of science, and (2) any claim to scientific knowledge must cohere with what science tells us of the nature and capabilities of human minds, i.e., as brains that are products of natural selection and embedded in their particular natural and cultural environments.

Rosenberg, of course, believes that God does not exist and that the belief that he does exist is totally unreasonable. The point I want to stress here is that whatever his reasons for this conviction, his scientism has literally no bearing on it.  Scientism, and thus naturalism, as he understands it, is entirely consistent with theism.  That theism and scientism are consistent in the narrow sense of there being no contradiction in believing both is, I assume, too obvious to be worth defending. No well-confirmed scientific theory refers to God and, while it is conceivable that in conjunction with other things we know a well-confirmed theory implies that there is no God, plainly no such things are in the offing.

Although I don’t think this claim requires a serious defense, a case that is in some respects parallel seems worth noticing.  Those who accept scientism remain in need of some sort of account of mathematics.  Some naturalists—Quine is the salient example—deny the fundamental difference between mathematical and scientific truth and regard the truths of mathematics as differing from those of the natural sciences only with respect to their extreme generality.  They dispense with the traditional view that the truths of mathematics are necessary while those of the sciences are contingent. Those who do not, and think that mathematics differs from science in a categorical way, agree that science is our best way of knowing but with an implicit scope restriction: it is our best way to know contingent reality, but mathematics as a way of knowing is epistemologically superior to science.  In the event that a well-confirmed scientific theory conflicts with a theorem of mathematics, then it is unreasonable to believe science.  Science trumps any competing claim about the contingent natural world, but mathematics trumps science. This is so obvious as to be unremarkable: hypotheses that have false mathematical implications are rejected out of hand; they’re not worthy of empirical testing. Naturalists who adhere to the contingent science/necessary mathematics distinction owe an account of the ground of mathematical truth and the roots of our mathematical knowledge, one that coheres with scientific knowledge in the two ways built into Rosenberg’s definition of scientism.  One familiar form an account can take is mathematical Platonism, the idea that mathematical knowledge is knowledge of a transcendent, non-empirical realm of mathematical objects. I don’t believe this, and I don’t think it coheres in plausible ways with theism, but Platonists believe that they possess good reasons to believe it, e.g., that it best explains the nature of mathematical truth and discovery, or that it best explains the (to some) amazing applicability of mathematics to the description of the natural world.  At face value, whatever the force of these reasons, they do not appear to be at odds with the well-confirmed theories of science, which are to all appearances silent on the metamathematical issues.  Mathematical Platonism’s belief that there is a categorically different reality beyond the world science accesses is not incompatible with scientism.  Nor is the theist’s analogous belief that there is a deity.

However, the theist is in a more comfortable position vis-à-vis naturalism than the mathematical Platonist. The latter faces a fairly serious problem of how the human mind can know anything about the mathematical objects his theory postulates.  On the plausible assumption that these eternal non-physical realities are causally inert they can have no effect on the physical world and the evolved material minds it contains. This constrains the possibility of knowing it in ways analogous to perception, which, as it happens, is often embraced by Platonists as a way to conceive mathematical intuition. The Platonist is more at home with the anti-naturalist dualist view of the mind as transcending physical reality. The theist (assuming that he dispenses, as he ought, with divine timelessness and immutability) has no parallel problem: if there is a God then he can make things happen in the material world and reveal himself to the likes of us. We have no need to posit powers of mind foreign to scientific knowledge of our evolved brains.  Mathematical Platonists and theists can accept Rosenbergian scientism (and naturalism), but it’s easier for the theist. There are, or might be, good reasons to believe in realities beyond the ken of the sciences, and to believe so is not at odds with scientific naturalism.

Anyway, the interesting question is not about the logical consistency of science and theism, but whether what science tells us about the world is at all likely on the supposition that God exists.  If what science describes is a world not much like any world theists could reasonably anticipate, then theism is unreasonable. I assume that Rosenberg, and many others happy to call themselves naturalists, assume that:

                Prob(S|G) = low

Where S is our scientific knowledge of the world and G is theism.  But there is no reason to believe this. So far as bare, generic theism goes, with no specification as to the nature of God or the reasons for which he creates

                Prob(S|G) = imponderable.

If we think there is a God but have nothing further to say about him we have no basis for regarding the claims of science as either likely or unlikely.  All we can say is that

Prob(S|G) ≠ 0

i.e., God could have created a world exactly like the one science reveals to us.

Once we add beliefs about God, we can easily get the low-probability judgment, e.g., if we believe not just that God exists but that he would have designed the human species, then

                Prob(S|G & D) = very low (if not 0).

As we have seen, Rosenberg (along with any number of theists) believes that this is a relevant judgment of prior probability, and it is, obviously, one on which theism comes out as not cohering with science, and thus as showing that there is no God.  But should those of us who believe G also believe D? Does theism (of the type we take to be true) really imply divine design? On my view it does not.  This is one of the ways in which a consideration not of generic theism, but of the particularities of biblical, Christian theism, brings us to a quite different conclusion about science: the world science describes is the kind of world we could have reasonably expected to find, assuming that the God of Christian faith is its creator. The crucial claim, not defended here, is that that God would not have chosen to design his creatures, but to bring them into existence by means of natural processes of the kind science describes.