An excellent debate from a couple of years ago

I re-read this exchange between J. D. Walters and Blue Devil Knight and was impressed by it. In spite of some acrimony, it is one of the best blog discussions I have seen on the relevant issues. It is illustrative of the difference between a naturalistic perspective and an anti-naturalistic one, and why it's so difficult to resolve the debate surrounding naturalism.

Naturalism without Physicalism?

Doctor Logic asked me what I thought the difference was between naturalism and physicalism. I think for anything to be "naturalistic" in any recognizable sense, it looks as if it has to have the characteristics of the physical that I mention: absence at the most basic level of purpose, intentionality, subjectivity, and normativity. It must be physical in at least these senses if it is naturalism is to have any meaning.

Sometimes people say that a physicalist will not allow abstract entities, but a naturalist can. But that's not going to do us any good in providing a naturalist response to the argument from reason. The AFR is about explaining how we come to have certain mental states. What do those abstract entities have to do with our coming to have mental states of a certain kind?

D. M. Armstrong once wrote; "I suppose that if the principles involved (in analysis at the physical level) were completely different from the current prinicples of physics, in particular if they involved appeal to mental entities, such as purposes, we might count the analysis as a falsification of naturalism."

Why Determinism is irrelevant to the argument from reason

Lewis's account of naturalism seems to imply that it does, although he mentions quantum-mechanical theories suggesting it does not. John Beversluis, in his treatment of Lewis's argument from reason, points out that Lewis does not consider or refute indeterministic forms of naturalism.

However, in dealing with more recent versions of the argument from reason the question of determinism is irrelevant, as I argued in a recent essay:

Exactly what does Lewis mean by naturalism? Very often the terms Naturalism and Materialism are used interchangeably, but at other times it is insisted that the two terms have different meanings. Lewis says,

“What the naturalist believes is that the ultimate Fact, the thing you can’t go behind, is a vast process of time and space which is going on of its own accord. Inside that total system every event (such as your sitting reading this book) happens because some other event has happened; in the long run, because the Total Event is happening. Each particular thing (such as this page) is what it is because other things are what they are; and so, eventually, because the whole system is what it is.”

As a presentation of naturalism, however, this might be regarded as inadequate by contemporary naturalists, because it saddles the naturalist with a deterministic position. The mainstream position in contemporary physics involves an indeterminism at the quantum-mechanical level. Lewis himself thought that this kind of indeterminism was really a break with naturalism, admitting the existence of a lawless Subnature as opposed to Nature, but most naturalists today are prepared to accept quantum-mechanical indeterminism as part of physics and do not see it as a threat to naturalism as they understand it. Some critics of Lewis have suggested that his somewhat deficient understanding of naturalism undermines his argument. Lewis, however, insisted on “making no argument” out of quantum mechanics and expressed a healthy skepticism about making too much of particular developments in science that might be helpful to the cause of apologetics.
However, contemporary defenders of the Argument from Reason such as William Hasker and myself have developed accounts of materialism and naturalism that are neutral as to whether or not physics is deterministic or not. Whatever Lewis might have said about quantum-mechanical indeterminacy, the problems he poses for naturalism arise whether determinism at the quantum-mechanical level is true or not.
Materialism or naturalism, as we understand it, is committed to three fundamental theses.
1) The basic elements of the material or physical universe function blindly, without purpose. Man is the product, says Bertrand Russell, of forces that had no prevision of the end they were achieving. Richard Dawkins’ exposition and defense of the naturalistic world view is called The Blind Watchmaker: Why the Evidence of Evolution Reveals a World Without Design not because no one ever designs anything in a naturalistic world, but because, explanations in terms of design must be reduced out in the final analysis. Explanation always proceeds bottom-up, not top-down.
2) The physical order is causally closed. There is nothing transcendent to the physical universe that exercises any causal influence on it.
3) Whatever does not occur on the physical level supervenes on the physical. Given the state of the physical, there is only one way the other levels can be.

These three claims can be true if "the physical" is deterministic or not. Even if there are no determining physical causes, if all that makes it undetermined and is nothing but brute chance, this hardly introduces libertarian free will or reason.

Dialogue with Shygetz on DC

VR: So when we say mental states are brain states, what do we mean?

Shygetz: We mean that each mental state corresponds to one and only one brain state. However, you labor under the misconception that when you think "apple" and I think "apple" we have the same brain state. We do not--when you think "apple" what color fruit are you imagining? What size, what exact shape, shiny or dull, alone or in a context? If "apple" doesn't refer to a single unique physical state, what makes you think it refers to a single unique mental one.

VR: There are, of course, various chairs, some made of different stuff and some different colors, but there is something that makes them all chairs. Doesn't everyone's thought of an apple have to have something physical in common if it is a physical state.

More, A can correspond to B without being identical to B, so there has to be more to identity than correspondence.

Causal role is determined by physical structure. If there is nothing about the property "being a thought about a pencil" that is identical to some particular physical state-type, then the mental state-type cannot be causally relevant.

Shygetz: And the only way you can do this is to posit something that interacts intimately with physical matter and can be strongly affected by physical matter while remaining somehow distinct from physical matter in some manner you have yet to even attempt to explain. I hope you are not trying to imply that dualism is more simple than physicalism, because it is not by some undefined by doubtlessly large amount. You are positing an entire new branch of physics based on a substance that violates its current laws.

VR: No problem. We need this one in order to preserve the logical foundations of science.

Shygetz: Yet again, you make a bald assertion that actually flies in the face of (admittedly incomplete) evidence. Do you have any evidence that this is true? If so, by all means present it. If not, you are not making an argument--you are declaring by fiat. Argument is necessary, sir; I don't think anyone here will be convinced by raw audacity. Show me a reason to think that physical data are insufficient to determine mental states--otherwise, you merely continue to beg the question.

VR: It's very simple really. Identity claims are necessary truths. In order for physical states to determine intentional states uniquely, it must be logically contradictory to deny the mental state once the physical information is given. Postulate any amount of physicalistic information you want, and you will never get anything that logically entails the existence of a mental state. The only way to get an argument that has a conclusion "X is about B" is to have intentional states in the premises. It doesn't matter how much physical information you give, it will always be logically possible for me to deny the existence of the mental state without logical contradiction.

The irreducibility of intentional states to physical states is held by many philosophers, many of whom, like Donald Davidson, are philosophical naturalists. There is also the argument that intentional-state attributions involve normative elements, and therefore, cannot follow necessarily from the existence of physical states. Many naturalists accept a dualism of properties but try to avoid a dualism of substances. The problem then arises as to how those nonphysical properties fit into a physical world, and also how non-physical properties can possibly be causally relevant.

Shygetz: Ah, now you are at least starting down the right path. Have you ever, and I mean EVER, added, subtracted, or manipulated powers in a mental vacuum? No; you always bring along your "unique perspective" which changes your mental state. Computers can add in a vacuum; if I take two identical computers and have one add 2 + 2, then take another computer and manipulate its physical states so they replicate the first one exactly, the second computer will have added 2 + 2. What is the reason to think that the human brain is different when adding 2 + 2?

VR: Computers have no first-person perspective. Therefore, they do not literally add 2 + 2. They do not perceive the relationship amongst the meanings. We perceive those relationships. However, physical facts are not perspectival. If my perspective determines how atoms go in my brain, we have a non-publicly accessible fact that determines physical states. That's not considered good naturalism.

It's like taking a bunch of indicative facts about the world and concluding the existence of an objectively binding moral obligation. You have to wrong type of facts on the one side to draw the proper conclusions on the other.

You have to go from facts are not subjective or perspectival, not normative, not intentional, and not purposive, and yet these facts have to entail truths that are subjective/perspectival, normative, intentional and purposive. That is a good deal more than just a question about how the bacterial flagellum got engineered.

Some replies to poeple on Debunking Christianity

VR: Because physically identical worlds can have different mental contents in them, and in a physical world identical to this one there are no one with any mental states at all. In that world, everyone is a zombie.

Zilch: Victor, do you have any evidence for this? Unless you can demonstrate that mental contents are not physical states, you are begging the question.

VR: Because, no amount of physical information can entail any definitive conclusion concerning mental content. This is the point of arch-naturalist W. V. Quine's argument for the indeterminacy of translation in Word and Object. Physical facts do not logically entail mental facts, just as physical facts do not logically entail moral facts. Getting an "about" from an "is" is just as impossible as getting an "ought" from an is, and for much the same reason. Even if mental states were token-identical to brain states, the brain facts do not and cannot entail the mental facts. So why do the mental facts exist?

Shygetz: Let's assume that a sense of purpose can possibly be couched in matter, and see if our observations are consistent with such an assumption. If such a sense could be arrived at by incremental change in a reproductive element, and if such a sense would increase reproductive success, then such a purpose would be arrived at through evolutionary processes. When we look at the evolutionary record, we see gradual increases in mental sophistication, which seem to correlate with increases in consciousness (e.g. the most mentally sophisticated non-human animals are also the ones with the most signs of consciousness). Were duality true, then there is no obvious reason for physical brain sophistication to correlate with cosciousness.

VR: Evolution can explain the development of mental states only if mental contents can play a causal role. If mental contents are epiphenomenal, then they are invisible to evolution. If the physical is causally closed, and physical states are insufficient to determine mental contents, that means that mental contents are epiphenomenal. It doesn't matter what they are or whether they exist or not. The physical will go its merry way regardless of them, and evolution, if it is purely physicalistic, will select for the physical substrate regardless of what the mental content is. Therefore the argument that reliable belief-forming mechanisms will be selected for by evolution goes by the boards.

Shygetz: Does consciousness increase fitness? Well, we are reproductively succeeding much more than our closest primate cousins that posess less consciousness, so I would say probably. So, it seems plausible that consciousness would evolve if it were couched in physical matter.

VR: This is considered to be a huge problem, however, which David Chalmers calls the Hard Problem of Consciousness. How can consciousness be physical. Plenty of people, like Chalmers, Colin McGinn, and even Jaegwon Kim, think that this is a complete mystery from the point of view of naturalism.

VR: You have not demonstrated that such a world is possible given the laws of the universe, and until you do you merely beg the question. The philosophical zombie is an impossibility if mental states are couched in physical states, and to simply argue that you can conceive otherwise is pointless. I can conceive of gravity being a repulsive force, but that doesn't demonstrate that gravity is not an attractive force.

VR: What do you mean by "couched in " physical states. Do you mean type-identical to physical states, or token-identical states, or supervenient upon physical states. I can conceive of a philosophical zombie without contradicting myself. If it isn't a self-contradictory idea, then it's logically possible, and we need to know why it is not the case.

Shygetz: If you are driven to postulate God, then you have just failed at science. God explains everything, and therefore nothing; it cannot be tested or disproven, and is worthless as an explanitory unit. God cannot be tested by science because it is not a coherent idea--it changes with the whim of the faithful to always remain a step away from the edges of science.

VR: One can conceive God in such a way that one can make testable theistic hypotheses. Lots of people say that theistic claims are untestable, but no one ever proves it. There are circumstances under which I would predict a miracle. And how about this "If God were to resurrect someone today, it would be more likely to be Mother Teresa than Adolf Hitler." That's a probabilistic expectation. If God resurrects Hitler, that disconfirms my theory.

Lewis on Supernaturalism

What Lewis means by "supernatural"
To call the act of knowing--the act, not of remembering that something was so in the past, but of 'seeing' that it must be so always and in any possible world--to call this act 'supernatural', is some violence to our ordinary linguistic usage. But of course we do not mean by this that it is spooky, or sensational, or even (in any religious sense) 'spiritual'. We mean only that it 'won't fit in'; that such an act, to be what it claims to be--and if it is not, all our thinking is discredited--cannot be merely the exhibition at a particular place and time of that total, and largely mindless, system of events called 'Nature'. It must break sufficiently free from that universal chain in order to be determined by what it knows. From Miracles, Chapter 3.

Is God supernatural?

I wouldn't even necessarily call God supernatural. There could conceivably be a science studying God's actions, based on which we could make predictions. If God would let us, we could even perform experiments on Him. What's wrong with this idea?

A response to some people on Debunking Christianity

I was explaining the structure of the argument, not attempting to defend the premises. I was making the rather narrow point that Parsons had the structure wrong. At least the argument I have endeavored to defend does not have that kind of structure, and I don't think Lewis's did either.

I dislike using terms like "magical" or "supernatural." I prefer to argue that if there is to be reason in the world, intentional explanations must be basic explanations. Nor am I denying that physical states can be correlated with mental states, or that physical changes can cause mental changes. What I am saying is that when you add up all the truths about how physical states are arranged, they don't entail any unique truths about what the mental states are. Physical states don't, and can't entail mental states, in much the way they don't and can't entail moral truths. Naturalists like Quine and Dennett agree with me on this. Do you think they are wrong?

Physical states, including states of a computer, are indeterminate with respect to mental states. This includes states of a computer playing chess. The programmers create a physical system which mimics proper chess-playing given a framework of meaning provided by humans. The move Rf6 on my computer screen, played by Fritz (who kicks my butt on a daily basis, in case anyone is wondering) has a meaning relative to my understanding of chess, which it itself lacks. It is only by anthropomorphizing the silicon monster do we get determinate meanings for its moves. The laws of chess have nothing to do with what the computer does, but human programmers give it the physical motions of a computer a context of meaning that allows is to see those moves as chess moves.

But if physical states are indeterminate with respect to meaning, can it be that we have no determinate mental states or proposotional attitudes? If so, then it is never literally true that we add, subtract, multiply or divide. Ever read Kripke on Wittgenstein? If we literally perform the operation 2 + 2 = 4, then we understand the meanings of 2, +, and 4. What are thoughts are about must be exactly those meanings. But the physical is indeterminate with respect to mental content. This means that determinacy of meaning must come from someplace other than the physical.

Or maybe we don't literally add, subtract, multiply and divide. We only simulate it. But how do we know what we're simulating, if that's the case.

Is the argument from reason a god of the gaps argument?

A. God of the Gaps
Another argument frequently advanced against virtually any piece of natural theology is the God of the Gaps charge. In fact, this is one of the most popular items in the atheist playbook. We know from the history of science that many things were thought in the past to require an explanation in terms of divine agency are now know to have naturalistic explanations. Rainbows, for example, were once thought to have been put in the sky as a sign, we now know that they can be naturalistically explained in terms of light refraction. Various biological systems show a harmony between means and ends which in the past was cannon fodder for the design argument, but is now explicable in terms of random variation and natural selection. So if there is something that we think cannot be explained in physical terms, just give science some time, and they’ll figure it out sooner or later.
An instance where the God of the Gaps objection appears strong is in the case of Newton’s account of the orbits of the planets. His theory would have expected the orbits to go somewhat differently from the way they go, and so he postulated God as the one who keeps the planets in line. Laplace later developed a theory that didn’t require this kind of divine tinkering, and when asked about Newton’s theistic theory he said “I have no need of that hypothesis.”
However, I am not sure that every argument that points to an explanatory difficulty for the naturalist can be effectively answered with a “God of the Gaps” charge. Consider, for example being at a dinner party with someone who is given a large amount of water and creates from it an equal volume of wine. (It tastes like really good wine, not that California cheap stuff). Can we reasonably say that this we just have a gap in our understanding. As Robert Larmer points out, our understanding of how wine is made is precisely what makes it so difficult to explain naturalistically.
What should be at issue in assessing “God of the gaps” arguments is whether they have met these conditions. Claims regarding events traditionally described as miracles and claims regarding the origin and development of life are where “God of the gaps” arguments are most commonly met. In the case of events traditionally described as miracles, it seems very evident that our increased knowledge of how natural causes operate has not made it easier, but more difficult, to explain such events naturalistically. The science underlying wine-making is considerably more advanced today than it was in first century Palestine, but our advances have made it even more difficult to explain in terms of natural causes how Jesus, without any technological aids, could, in a matter of minutes, turn water into high quality wine. Indeed, it is the difficulty of providing a naturalistic account of such events that leads many critics to deny that they ever occurred; though this looks suspiciously like begging the question in favour of naturalism. It is clear that if such events have occurred, the advance of science has made them more, rather than less, difficult to explain in terms of natural causes. Employing a “God of the gaps” argument that the occurrence of such events would constitute good evidence for supernatural intervention within the natural order seems entirely legitimate.
Perhaps even Newton has been given a bad rap, as Plantinga points out:
Newton seems ... to have suffered a bum rap. He suggested that God made periodic adjustments in the orbits of the planets; true enough. But he didn’t propose this as a reason for believing in God; it is rather that (of course) he already believed in God, and couldn’t think of any other explanation for the movements of the planets. He turned out to be wrong; he could have been right, however, and in any event he wasn’t endorsing any of the characteristic ideas of God-of-the-gaps thought (“Methodological Naturalism” Pt. II, Origins and Design, Vol. 18, No. 2, Footnote 52).
So, I would maintain that there are gaps and there are gaps. It’s not just pointing to an unsolved engineering problem in nature. First of all, the categories of the mental and the physical are logically incompatible categories. You start attributing mental properties to physics and you might end up being told that you are no longer describing the physical at all. Purpose, normativity, intentionality or about-ness, all these things are not supposed to be brought in to the physical descriptions of things, at least at the most basic level of analysis.
Let’s consider the gap between the propositional content of thought and the physical description of the brain. My claim is that no matter in how much detail you describe the physical state of the brain (and the environment), the propositional content of thought will invariably be undetermined. This isn’t my claim of C. S. Lewis’s, this argument was made by the arch-naturalist W. V. Quine. Now of course that doesn’t make it true, but nevertheless it’s not a matter of getting a physical description that will work, In my view the logico-conceptual gap is always going to be there regardless of how extensively you describe the physical. As I said earlier, bridging the chasm isn’t going to simply be a matter of exploring the territory on one side of the chasm.
Second, to a very large extent the gap between the mental and the physical was caused by science in the first place. The way one got physics going in the early days of modern science was to attribute such things as colors, tastes, smells, to the mind, while explaining the physics of it without having to consider these things. So, for example, in reducing heat to the mean kinetic energy of gases, science “siphoned off” the feeling of warmth caused by heat to the mind, and explained heat without reference to how heat feels to us. As Swinburne put it.
There is a crucial difference between these two cases. All other integrations into a super-science, or sciences dealing with entities and properties apparently qualitatively distinct, was achieved by saying that really some of the entities and properties were not as they appeared to be; by making a distinction between the underlying (not immediately observable) entities and properties and the phenomenal properties to which they give rise. Thermodynamics was conceived with the laws of temperature exchange; and temperature was supposed to be a property inherent in an object. The felt hotness of a hot body is indeed qualitatively distinct from particle velocities and collisions. The reduction was achieved by distinguishing between the underlying cause of the hotness (the motion of the molecules) and the sensations which the motion of molecules cause in observers. The former falls naturally within the scope of statistical mechanic—for molecules are particles’ the entities and properties are not of distinct kinds. But this reduction has been achieved at the price of separating off the phenomenal from its causes, and only explaining the latter. All reduction from one science to another dealing with apparently very disparate properties has been achieved by this device of denying that the apparent properties (i. e. the ‘secondary qualities” of colour, heat, sound, taste, etc.) with which one science dealt belonged to the physical world at all. It siphoned them off to the world of the mental. But then, but when you come to face the problem of the sensations themselves, you cannot do this. If you are to explain the sensations themselves, you cannot distinguish between them and their underlying causes and only explain the latter. In fact the enormous success of science in producing an integrated physico-chemistry has been achieved at the expense of separating off from the physical world colours, smells, and tastes, and regarding them as purely private sensory phenomena. The very success of science in achieving its vast integrations in physics and chemistry is the very thing which has made apparently impossible any final success in integrating the world of mind into the world of physics.
If Swinburne is correct here, the very thing that made reduction possible in many historic cases is going to make it impossible in the case of the mind and matter.
I conclude, therefore, that “God of the gaps” or even a “soul of the gaps” response to the argument from reason does not work. I am not saying that we just cannot figure out right now why the mental states involved in rational inference are really physical, I am suggesting on principled grounds that a careful reflction on the nature of mind and matter will invaribly reveal that there is a logical gap between them that in principle can’t be bridged without fudging categories.

Reply to a point in Loftus' review of Beversluis

From John Loftus' Review of Beversluis

The Argument From Reason, as best seen in Lewis’ book, Miracles, “is the philosophical backbone of the whole book,” from which “his case for miracles depends.” (p. 145). Lewis champions the idea that if naturalism is true such a theory “impugns the validity of reason and rational inference,” and as such, naturalists contradict themselves if they use reason to argue their case. If you as a naturalist have ever been troubled by such an argument you need to read Beversluis’ response to it, which is the largest chapter in his book, and something I can’t adequately summarize in a few short sentences. Suffice it to say, he approvingly quotes Keith Parsons who said: “surely Lewis cannot mean that if naturalism is true, then there is no such thing as valid reasoning. If he really thought this, he would have to endorse the hypothetical ‘If naturalism is true, then modus ponens is invalid.’ But since the consequent is necessarily false, then the hypothetical is false if we suppose naturalism is true (which is what the antecedent asserts), and Lewis has no argument.” (p. 174).

In response to Parsons' comment, that's not how the argument from reason goes. If naturalism is true, then no one ever performs a modus ponens inference, and this can be for a number of different reasons.

1) If naturalism is true, then there are no propositional attitudes. Propositional attitudes are necessary for modus ponens inferences, so no one would actually ever perform a modus ponens inference if naturalism is true.

2) If naturalism is true, then there is no mental causation. One mental event cannot cause the occurrence of another mental event in virtue of its content, if naturalism is true.

3) If naturalism is true, then logical laws have no psychological relevance. Only physical laws can be relevant to physical events if naturalism is true; logical laws will be followed only if the physical order to disposes the brain to follow them. There could be arguments in accordance with reason but never from reason, to use Kantian terminology. I'm not saying that if naturalism is true there would be no logical laws, but rather those laws would not and could not have anything to do with what anyone things.

In other words, the argument says that if naturalism is true, then no one reasons validly. Modus ponens would be eternally a valid form of inference, but that fact would be completely irrelevant to any actual reasoning processes, and would be inoperative.