Sunday, July 15, 2007

Mapping Dualism and Materialism

This post is redated and expanded. Sometimes, when I hear discussion of dualism vs. materialism, I have to wonder how, exactly, the map is being drawn between those positions. What exactly is going to count as dualism or materialism. Just as materialists wonder if defenders of materialism have read or understood the major figures in materialist philosophy, so I sometimes wonder if defenders of materialism are familiar with the different varieties of dualism that have been defended in recent years. For example, William Hasker's defense of dualism, found in The Emergent Self, is certainly far from insensitive to the developments in neuroscience, and is attentive to the close correlation between mental states and brain states that have been mapped by neuroscientists. In fact, neuroscience provides the primary basis for Hasker's defense of an "emergent" dualism as opposed to a traditional Cartesian dualism. See especially the discussion on pp. 153-157 and 197-198, and there is even a footnote reference to D. Frank Benson's The Neurology of Thinking (Oxford 1994). I have yet to see anyone grapple with Hasker's book from a materialist perspective, which is too bad. I guess I've done more to solicit materialist response than he has, but he really does offer an across-the-board case against materialism and a well-developed anti-materialist theory to challenge it, and I really didn't do that. It isn't clear to me that we know, without further clarification, what is meant by terms like "materialism," "substance dualism," "property dualism," and other terms that have been used so often that we are lulled into thinking that we know exactly what they mean. I provided a typology of positions in the philosophy of mind in my review of Kevin Corcoran ed. Soul, Body and Survival (Cornell, 2001). (Faith and Philosophy July 2004, 393-399. Standard or Cartesian dualism is committed to these four claims: 1. The mental is sui generis, existing independently of the physical and not in any way reducible to it. 2. Mental states inhere in a thinking thing or substance, not in a bundle. 3. Mental states do not have a location in space. 4. Souls are created individually by God ex nihilo,; they do not emerge from pre-existing material states. However, I would consider myself a dualist and have some doubts about both 3 and 4. William Hasker and Brian Leftow would be examples of non-standard dualists whose views are represented in the Corcoran volume. Hasker is an emergent dualist and Leftow is a Thomistic dualist. Standard materialism requires three theses: 1. Physics is mechanistic and is to be described in purely non-mental terms. 2. Physics is causally closed. 3. All states that are not physical supervene on physical states. Typically a materialism, for example, should not maintain that there is such a thing as libertarian free will, because libertarianism requires the existence of fundamental purposive explanations. But Peter van Inwagen, for instance, calls himself a materialist in the philosophy of mind but also is a defender of libertarian free will. Lynne Baker calls herself a materialist but her first book on the philosophy of mind was an attack on physicalism. So there are nonstandard forms of materialism, as well as nonstandard forms of dualism, and many "Christian materialists" actually reject one of more of the central theses of standard materialism. Good examples would be Lynne Rudder Baker, who calls herself a materialist but whose first book on the philosophy of mind was an attack on physicalism, and Peter van Inwagen, who believes in libertarian free will, (See his book An Essay on Free Will, from which is inconsistent with strict physicalism. I keep having to say this over and over again, especially when Babinski keeps pointing out that there must be something wrong with my arguments against physicalism because there are Christian philosophers who believe in a materialist philosophy of mind. First of all, if this were true then you could refute any argument for materialism on the ground that some atheist philosophers, like C. J. Ducasse and J. McTaggart believed in life after death, and that atheist existentialist philosopher Jean-Paul Sartre was a Cartesian dualist, or that my college metaphysics teacher, Ted Guleserian, is both and atheist and a mind-body dualist. Now any of these may have good arguments for what they believe, but merely pointing out that they exist does not provide evidence for anything at all. In my book there is a detailed definition of physicalism, and a slightly broader defintion for naturalism. My arguments are directed against just those positions. Until I get a clear idea of what a person holds, it will not be clear to me if that person is a materialist or a dualist, or maybe a little of both. I keep pointing out, but apparently some people choose not to pay attention, that I could qualify as a materialist on some definitions. (In fact I once heard a paper by a dualist accusing C. S. Lewis of being a non-reductive materialist!) The kind of dualism William Hasker defends in his book The Emergent Self is called Emergent Dualism. I would appreciate it if people would kindly refrain from stereotyping my positions.

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21 Comments:

At 7/16/2007 06:44:00 AM , Blogger Darek Barefoot said...

Victor

The last segment of Nova Science Now invoked emergence to explain consciousness. Physicalist "emergence" (not Hasker's variety) is a strategy for offering dualist-style explanations while avoiding dualist ontological commitments. Nancey Murphy resorts to it as well. This tactic always asserts that we cannot predict the properties of the whole from the properties of the constituents in isolation. Left dangling is the question, Does this mean that the properties of the whole are not fully determined by the properties of the constituents?

Perhaps it is more useful to take up the issue in terms of supervenience of bodies of rules rather than properties. The laws of chemistry, optics, genetics and aerodynamics (to name just a few) supervene on the laws of physics. A change in the laws of physics is conceivable as a result of which the laws of chemistry would necessarily change. A change in the laws of chemistry is conceivable as a result of which the laws of genetics would necessarily fail to obtain. Are there conceivable changes in the laws of physics or chemistry as a result of which the rules of logic would cease to obtain? If not, then there is a hard explanatory dividing line between the mental and the physical. And the what dualism demands at a minimum, I think, is just such a hard dividing line.

 
At 7/16/2007 08:27:00 PM , Blogger Blue Devil Knight said...

A change in the laws of physics is conceivable as a result of which the laws of chemistry would necessarily change.

Technically, supervenience only means that if the laws of chemistry were different, the laws of physics would have to be different. This allows for the multiple realizability of chemistry.

 
At 7/17/2007 06:39:00 AM , Blogger Darek Barefoot said...

BDK

Thanks for the correction. By bringing up supervenience I invoked a field who subtleties I can't pretend to have mastered. More modestly put, there does seem to be a interdependence between the laws of physics, chemistry and genetics that underwrites the standard scientific accounts of chemical reactions having emerged in time from more basic physical interactions between particles, and of genetic mechanics having arisen from more basic chemical interactions. On the physicalist account, shouldn't we expect the same kind of interdependence between the laws of chemistry and physics and the rules of logic? But I don't think we see it in the last case. The rules of logic seem to stand aloof. However the rules of logic should be formulated, the proper formulation would hold even if physics, chemistry, genetics and metabolic processes worked differently, wouldn't it?

 
At 7/18/2007 04:10:00 PM , Blogger Blue Devil Knight said...

On the physicalist account, shouldn't we expect the same kind of interdependence between the laws of chemistry and physics and the rules of logic?

I don't see why, unless you have a foundationalist view with logic at the bottom, which I don't have.

Also, note that supervenience formulations of physicalism were specifically developed to avoid the various complications associated with debates about reductionism. Many, if not most, naturalists are nonreductive materialists, but believe that biological and other properties supervene on physical properties (as opposed to believing that biological theories are reducible to physical theories). I am not aware of any consensus view about logic/mathematics amongst naturalists, other than antiplatonism (which is essentially restating a commitment to naturalism).

My take on the relation between logic and the rest of the sciences is strongly influenced by Gila Sher's wonderful work, two examples of which are Is logic a theory of the obvious? and Logical consequence: an epistemic outlook.

Gila makes a place for the specialness of logic, its relative stability compared to the empirical sciences. At the same time she allows for the possibility of empirical modifications of logic, of developments in logic that are driven partly by science and not just conceptual considerations.

 
At 7/19/2007 09:07:00 PM , Blogger Darek Barefoot said...

BDK

I had to read those articles pretty quickly. Nevertheless, I have not so far seen how Sher's points undercut my own. For example, she says:

"Consider any scientific discipline, say, physics or biology. Due to the generality of logic, the laws of logic hold in biology. But, since formal properties--and hence logical constants--do not distinguish the biological features of objects, our theory of formal structure--hence logic--is independent of biology. Our biological theories have to respect the laws of logic (to be 'logically sound'), but our logical theories do not have to respect the laws of biology (to be 'biologically sound'). Since biology is dependent on logic but logic is independent of biology, logic appears to be more basic than biology. The same relation holds between logic and other sciences."

I haven't yet seen where she addresses the possible problem this poses for naturalism.

Scientists seem to believe that that the actual laws of chemistry are determined by the actual laws of physics. It is counted as evidence for the truth of quantum theory, for example, that it entails the laws of chemistry. Even if there are alternate physical laws that also would entail the actual laws of chemistry, all conceivable alternate laws of physics would not do so. Even supervenience implies this. If there are conceivable alternate laws of chemistry that would require alternate laws of physics, then the actual laws of chemistry would not obtain under all conceivable physical laws.

But logic is troublesomely exceptional. Whatever the actual rules of logic are, they are not determined by the laws of physics as the laws of chemistry or optics are. Otherwise, there would be possible worlds in which the rules of logic did not obtain because of differences in the laws of physics. And that notion is incoherent.

The trouble comes from naturalism's insistence on a single causal context. For example, the assumption of a single causal context embracing both chemistry and physics--combined with the explanatory value of both sets of laws-- is, I think, the reason for the justifiable belief that the laws of chemistry are determined by the laws of physics. The rules of logic have explanatory value for at least some mental processes. Yet the rules of logic do not stand in relation to the laws of physics the same way that the laws of chemistry, optics, aerodynamics, etc. do. No matter how imperfect our grasp of the rules of logic, it cannot be the case that they are determined by the laws of physics (or biochemistry). Therefore those processes for which the rules of logic have explanatory value do not occur within the same causal context as do processes that conform to those other bodies of law. More than one causal context means dualism at a minimum.

 
At 7/20/2007 07:44:00 AM , Blogger Blue Devil Knight said...

Yes, you should read the papers. I don't have time right now to enter this discussion with any depth, unfortunately. The papers form a nice story about the relation of logic to the special sciences. Not only that, I think she is probably right.

 
At 7/20/2007 11:57:00 AM , Blogger Doctor Logic said...

darek,

The problem with your argument is this. Non-contradiction is a property of physics. That is, physics is logical. Therefore, it's perfectly plausible that a system could evolve to be sensitive to that property. That system has evolutionary advantage when it generically predicts what must logically be.

Another way of putting this: you cannot have a lawful system that is not logical. Logic is implicit in any lawful system. So how can you talk about the laws of physics as if they don't have laws of logic built-into them?

 
At 7/20/2007 08:59:00 PM , Blogger Darek Barefoot said...

DL

>Another way of putting this: you cannot have a lawful system that is not logical.<

The mental processes of a psychotic are lawful. It is presumably because the brain of a psychotic is slavishly obedient to the laws of chemistry that the mental processes it produces are not logical.

The naturalistic argument that I have encountered runs something like this. All processes are natural in that they are determined by and dependent upon the processes described by an ideal physics. (Note, this does not necessarily mean that they are all reducible to physics.) But on that assumption, the rules of higher level processes are determined by and dependent upon the rules of an ideal physics. Logic or the rules of rational inference are the rules of a higher order process, namely, rational thought. Therefore the rules of logic are determined by and dependent upon the rules of physics. If the rules of logic are determined by and dependent upon the rules of physics, then there are conceivable changes in the rules of physics that would result in changes in the rules of logic (as is the case with rules of chemistry, genetics, optics, etc.). However, changes in the (actual) rules of logic are inconceivable, therefore the naturalistic argument fails.

Here is another way to come at the question. When a scientist studies a beaker full of reacting chemicals, he does not speculate that the chemicals will combine a certain way because they understand that doing so is rational; the chemicals will combine as they do because the laws of chemistry so dictate. Why is it different when the beaker is a human skull? If all human behavior is the product of chemicals combining, and if chemicals need not bother about the logic of what they are doing in order to combine, then why is logic necessary for any variant of human behavior?

The naturalist replies, metallic elements don't generally fly through the air, but if they get into just the right arrangement--an airplane wing--they do. They then obey certain special laws, too, the laws of aerodynamics. But this is just a surprising result of their more basic physical properties and the outworking of more basic physical laws. The flying of a metallic airfoil and the rules that govern it are entirely determined by and dependent upon the underlying physics. The same is true, they claim, of chemicals in a brain getting together and thinking rationally. But this kind of analogy will not stand up to analysis.

 
At 7/20/2007 09:28:00 PM , Blogger Blue Devil Knight said...

Therefore the rules of logic are determined by and dependent upon the rules of physics. If the rules of logic are determined by and dependent upon the rules of physics, then there are conceivable changes in the rules of physics that would result in changes in the rules of logic (as is the case with rules of chemistry, genetics, optics, etc.). However, changes in the (actual) rules of logic are inconceivable, therefore the naturalistic argument fails.

Changes in the rules of logic are quite concievable. Trivalent logics, quantum logics, and other very strange logics are not only conceivable but actual, with some of the changes generated by considerations in science.

Sher talks about this stuff in both of the articles I mentioned.

To say that the rules of logic are dependent on the laws of physics would be very strange, though. It is more complicated than all that. Sher's article 'Is logic a theory of the obvious' gets at some of these questions. It is clear nobody here has read Sher's work, so I'll just bow out now before I get sucked into something more time-consuming than illuminating.

 
At 7/21/2007 07:40:00 PM , Blogger Darek Barefoot said...

BDK

I may be going out on a limb here, since I have not finished reading Sher's second article. However I don't believe that she is saying that the actual rules of logic could change, only our understanding of the rules. That is why I included the qualifier "actual" in my previous post. This distinction is parallel to that between scientific laws and laws of nature.
There is a difference between saying that our understanding of the rules of logic could change (or be different) and that the rules themselves could change (or be different).

 
At 7/22/2007 10:28:00 PM , Blogger Doctor Logic said...

darek,

You said:

Logic or the rules of rational inference are the rules of a higher order process, namely, rational thought.

Yes, but they are not the rules of human thought. No one thinks purely rationally, just like no one can see light perfectly well.

If you follow your logic, then you would have to argue that there's no reason why eyes should be able to focus. When a falcon focuses on prey, there's a complex process of brain sending messages to muscle via nerves that also return data from the retina. Yet, the laws of optics do not causally force this process to work. Nerve-firing mechanisms in the falcon's brain are not miniature optical focusing events. They are biochemical signals like the ones that account for hearing and flight. The laws of optics merely make it possible for the falcon to focus, and provide a way for the falcon to obtain an advantage.

Likewise, the human brain is not causally forced to think rationally. It consists of chemical and physical mechanisms that approximate rationality because of rationality's evolutionary advantages. Yet, the brain doesn't have to be perfect, nor be causally driven by some abstract logical laws. Just as neurons can't focus by themselves, neither does a single neuron need to be able to look at an abstract logical relation.

All along, you have assumed that the rational thought in our heads is causally controlled by laws of logic. It's as if you think we reach the next step in a syllogism because we must causally do so according to the laws of some platonic logical space.

But that's certainly not the only possible explanation. Indeed, I don't even think it's a valid explanation unless you can make a prediction based on your theory.

A far better theory is that brains are sophisticated physical machines that have been evolved or been trained to recognize abstract logical patterns. Successive steps in a syllogism are reached by a physical process that has been trained or conditioned to model abstract/symbolic relations.

 
At 7/23/2007 07:06:00 AM , Blogger Darek Barefoot said...

DL

Instead of addressing my argument your last post confuses the prescriptive and descriptive aspects of rules. The fact that rules are not merely descriptive does not mean that they have no descriptive value. The rules of optics can be viewed as a description of why a functional eye has a certain structure. The same rules prescribe that any eye must have a certain structure in order to function.

Likewise, the rules of logic describe how human thought proceeds in certain instances, that is, in instances of reasoning. They also prescribe how thought must proceed in order to derive rational conclusions from premises.

The Law of Universal Gravitation says that under certain conditions, apples fall. LUG also dictates to us that if we want an apple to fall, we must find or bring about certain conditions in order for this to occur.

From traffic law we can derive a descriptive statement that when reaching a red light, cars will stop (with a high degree of probability, unless you drive in downtown Rome) and thereby collisions are minimized. It also prescribes that if collisions are to be minimized, cars must stop when reaching red lights.

The rules of logic, to the extent that they are indeed rules, are comparable to other rules such as physical laws. But rules of logic are not connected to laws of nature the same way various laws of nature (higher lower and lower order laws) are connected to one another, yielding at least two related but distinct domains of rules. Note that both of the articles BDK refers to by Gila Sher confirm the first clause of my immediately preceding sentence without going as far as my conclusion.

 
At 7/24/2007 06:31:00 PM , Blogger Doctor Logic said...

darek,

Sorry for the delay. I'll try to tie some things together.

A couple of comments back, you asked:

If all human behavior is the product of chemicals combining, and if chemicals need not bother about the logic of what they are doing in order to combine, then why is logic necessary for any variant of human behavior?

It's not necessary per se. It's advantageous from a survival perspective because it enables humans to model their environment. It's only necessary to the extent that you say that survival is necessary, which it is for us to have reached our present place in evolutionary history.

If you don't contest these facts (you don't appear to do so explicitly), then you would admit that there is a causal connection (if not a well-understood one) between the logical structure of the universe and logical modeling ability (rationality) in humans. In principle, a lawful, logically structured world presents a survival advantage to a species that can think abstractly about logic.

You also said:

But on that assumption, the rules of higher level processes are determined by and dependent upon the rules of an ideal physics. Logic or the rules of rational inference are the rules of a higher order process, namely, rational thought. Therefore the rules of logic are determined by and dependent upon the rules of physics.

I don't know any materialists or naturalists who think that the laws of logic are determined by physics. At least, not unless they think that the laws of mathematics and computation ought to be considered physical laws.

However, in your last reply, you highlighted a distinction between "descriptive" and "prescriptive" laws. I assume then that you mean that physical and computational laws (the "is") do not uniquely determine prescriptive facts (the "ought"). I would agree. Physical and mathematical laws cannot rationally prove that we "ought" to be rational (nothing possibly could).

In order to get from an "is" to an "ought," you need moral axioms. In your recent example, your moral axiom is "we ought to avoid collisions," and that converts the descriptive fact of how lights and traffic function into the prescriptive rule that one should stop at red lights.

But what moral axioms ought one accept? That question cannot be settled except by personal preference, which is non-rational. And in a naturalistic view, that preference is itself naturally determined by physics.

So I fail to see what your objection has to do with our discussion. Your goal is to show that naturalism is broken, but the concept of the absolute ought (which you seem to use in your argument) is non-natural, and so cannot be held against naturalism's self-consistency or sufficiency.

 
At 7/25/2007 04:38:00 PM , Blogger Darek Barefoot said...

DL

Well, things are broadening out here and there is not time and space to develop this in all directions. But for clarification . . .

Let's not confuse thought with behavior. It is behavior that is advantageous in the natural world, not thought as such. To carry this over into computing, say that we keep every chess-playing computer program that consistently wins chess games and discard those that do not. What determines whether the programs "survive" is what moves they make (their "behavior") not what they think in order to make the moves--or even if they think at all.

Given that chess programs work mechanically, most of us would be surprised if we somehow were to discover that they actually think. Even in the case of a program that can beat a chess grand master, we would be surprised to find that rational thought is going into its moves. So its surprising to contemplate that as organisms who only need to make "winning moves" in the context of our environment, we nevertheless think rationally about what we do.

>>I don't know any materialists or naturalists who think that the laws of logic are determined by physics. At least, not unless they think that the laws of mathematics and computation ought to be considered physical laws.<<

Many if not most naturalists are physicalists, and all materialists are. I have tried to point out a necessary implication of what they believe, whether or not that implication has occurred to them. If the ground level of reality is material (or, physical) then all higher order processes depend on more basic physical processes. Would the materialists you know dispute that? But if that is true, it means that the rules that pertain to higher order processes depend on the rules that pertain to basic physical processes, which I identified as the laws of an ideal physics. Mathematical realism is a deep subject in its own right. But I would not think it controversial to say that in physicalism the laws of computation depend on the laws of physics, not necessarily that they are "physical laws" as such. My argument proceeds from there.

>>In order to get from an "is" to an "ought," you need moral axioms. In your recent example, your moral axiom is "we ought to avoid collisions," and that converts the descriptive fact of how lights and traffic function into the prescriptive rule that one should stop at red lights.<<

Hold on! Moral axioms or rules are nowhere in sight here. "Prescriptive" as I was using it does not refer to moral imperatives, but to necessity underwriting predictability. The description that at some particular time cars stopped for red lights and there were no collisions does not in itself tell us that there is a necessary connection between cars stopping for red lights and the probability of collisions, a "rule" holding at all times under similar circumstances. The rule I had in mind was pragmatic, not moral: "To avoid collisions, cars must stop at red lights," not, "To be an ethical person one ought to stop at red lights."

Likewise, it may be ethical to think logically, but logical necessity exists apart from moral considerations. To think rationally, it is necessary to think certain ways (ways that respect logical necessity) and if someone fails to think those ways, the person is not thinking rationally--regardless of the ethics involved. In the case of physical cause-and-effect we have something called nomological necessity, which entails that physical processes must proceed (and are assumed to proceed) in certain ways in order to be intelligible. But physical processes in the brain can proceed intelligibly while associated mental processes may not proceed rationally.

 
At 7/25/2007 08:17:00 PM , Blogger Doctor Logic said...

darek,

Let's not confuse thought with behavior. It is behavior that is advantageous in the natural world, not thought as such.

You started by talking about why a physical system would use reason. I showed that it would because the world is logical, and the application of reason leads to behaviors that have survival advantage. (Behaviors that are all but impossible without reason, e.g., building rocket engines according to scientific principles.)

Are you saying that a system can act as if it has general purpose abstract logical reasoning skills when it doesn't? Or are you raising the bar by saying that reasoning itself is just another behavior? In that case, what are you saying is missing?

I don't think your definition of physicalism is right. By your definition, a physicalist would have to say that the laws of mathematics were also physical. I know of no physicists who would say this, yet I would think of most physicists as falling into the naturalist/materialist/physicalist camp.

Your argument against physicalism is confusing. On the one hand, I showed how the logical structure of physics leads to an evolutionary advantage for animals that can reason. In that case, the reasoning ability of humans is predicted or "prescribed" by the logical structure of physics. That is, should a species accidentally develop correct reasoning, it will have an advantage over a being that doesn't have correct reasoning. IOW, there is a predictive mechanism that accounts for why our reasoning is correct.

So I fail to see what your objection is. You say:

But physical processes in the brain can proceed intelligibly while associated mental processes may not proceed rationally.

Yes, but irrational species have a relative survival disadvantage. So in a population of systems, some of which reason correctly, some of which do not, the correct reasoners will prevail by using their correct reasoning to advantage in their logical environment.

The burden on naturalism is not to show that all humans must use logic, but only to show that they should be expected to have a tendency to do so. And that's all they have - a tendency. Humans do not have a total guarantee of rationality, only a statistical tendency.

"Prescriptive" as I was using it does not refer to moral imperatives, but to necessity underwriting predictability.

Oops. I misunderstood you. :)

 
At 7/27/2007 12:10:00 PM , Blogger Darek Barefoot said...

DL
>>Are you saying that a system can act as if it has general purpose abstract logical reasoning skills when it doesn't?<<

"General purpose" in the above statement is a relative condition, designed apparently to sidestep my example from chess-playing programs. Playing chess at tournament level requires dealing with a complex array of possible inputs. As complex an array as driving a car? or as hunting bison? or as engaging in all activites of humans in Neolithic times? or human activites in the Bronze Ages? or future human activities we are presently ignorant of?

My claim is that computers can now engage in activities that humans can only engage in if they are conscious and rational, but we do not on that basis assume computers to be conscious and rational. We do not even compare the relative flexibility of response of computer programs in their environments with that of human subjects in theirs and then attribute consciousness and rationality to computer programs proportionally. As I believe I have mentioned before, this puzzle is recognized by (among others) Prof. Stevan Harnad, an authority on artificial intelligence who has a thoroughly secular Darwinian worldview.

But all that is beside the point. You cannot simply observe, correctly, that rationally-motivated behavior will be favored in the struggle for survival and then claim that that fact alone proves rational thought to be a physical process.

>>By your definition, a physicalist would have to say that the laws of mathematics were also physical.<<

To the extent that a physicalist denies that the laws of mathematics are physical and yet acknowledges that we are affected by them they are a problem for physicalism. I think that garden variety physicalists would tend to take mathematics as a kind of language needed for referring to physical properties and quantities, so that mathematical laws are "physical" to the extent that they are integral to physical laws. I may be stating it poorly, but I believe that would be the direction of their thinking.

Note, however, that brain functions always respect the mathematical aspects of physical laws, but associated thought processes may or may not respect mathematical rules. The same might be said of rules of logic. There is a logical aspect to laws of nature in that a law of nature cannot simultaneously obtain and not obtain, but brain chemistry always conforms to the logical aspects of laws of nature while thought processes may or may not coform to the rules of logic. So there is no solution here to the independence of rules of logic (i.e., rules of logical thinking) from physical laws.

As for defining physicalism, you might take a look at the Wikipedia article of the same name. Note what the article says about the importance of supervenience to physicalism. Supervenience does not work for rules of logic, however, as I have argued.

>>That is, should a species accidentally develop correct reasoning, it will have an advantage over a being that doesn't have correct reasoning.<<

You have hit upon something crucial. The grist for natural selection is indeed accidental changes to biological structures and processes. The problem is that the nature of a logical sequence of thought is fundamentally non-accidental. Thoughts cannot accidentally (or incidentally) follow one another and yet follow one another because of logical relationships obtaining between them. But rationality demands that thoughts follow one another because of those relationships, not because of a mechanism operating in incidental alignment with them.

Go back for a moment to the chess example. We probably agree that a human chess player can consciously contemplate the strategic value of a certain move and then make the move because of that evaluation. Let's label such a move a "strategically reflective move." Chess programs can make moves that are mechanically aligned with strategic reflection. But unless such programs are conscious, obviously they cannot make moves that qualify as strategically reflective.

The same is true of rationally reflective beliefs/decisions. A chance modification to a neurological process, resulting in a chance change in a thought sequence, cannot yield the kind of non-accidental sequence that constitutes reflective reason--even if such a sequence were to result in an advantageous behavior. In short, you can accidentally come to believe a fact, but you cannot accidentally possess a rational insight that leads you to believe the fact.

 
At 7/27/2007 05:01:00 PM , Blogger Doctor Logic said...

darek,

You cannot simply observe, correctly, that rationally-motivated behavior will be favored in the struggle for survival and then claim that that fact alone proves rational thought to be a physical process.

I'm not arguing that this proves rational thought is a physical process. I'm not the one making the strong claim, the AfR is. The AfR is the strong claim that naturalism is deficient. Yet, the AfR is not an argument that accounts for any of the details of naturalistic models. It's an argument that claims to show that no naturalistic model will ever suffice. My argument is merely that the AfR has no such power because, contrary to the AfR, there is a causal connection between laws of physics and mathematics and our reasoning ability.

As for physicalism, you seem to be attacking a form of physicalism in which:

1) There are physical laws,

2) It is declared that non-contradiction and identity are not physical laws nor separately universal laws,

and

3) Empirically, non-contradiction and identity affect our reasoning.

I think I too would attack such a view because I fail to comprehend what it would mean for there to be physical laws that did not implicitly claim that the laws were non-contradictory. How could I have any laws that said that "X is the case" without implicitly denying that "X is not the case"?

So, I think you are arguing against some sort of straw-man physicalism. Physicalism either has to argue that non-contradiction and identity are laws of physics, or else it must argue that they hold independently as de facto laws of physics. In which case, such laws most definitely affect us.

The grist for natural selection is indeed accidental changes to biological structures and processes. The problem is that the nature of a logical sequence of thought is fundamentally non-accidental.

I find this puzzling. The randomness of the inputs to natural selection is kind of irrelevant, right? Natural selection tames that randomness by selecting only those random entries that give an advantage. (Think of the classic box of shaped blocks with similarly shaped notches. If I shake up the box randomly, the cut outs fall into their notches by natural selection of the random shaking. c.f. "The Delicate Delinquent")

Indeed, even our thoughts work this way. Many of our thoughts proceed by random (or pseudo random) guessing, followed by pruning for logical consistency. (It's true that some thoughts follow by rote, but rote is a process that's even easier to model physically.)

You say:

But rationality demands that thoughts follow one another because of those relationships, not because of a mechanism operating in incidental alignment with them.

That's just what I have just described. Rationality doesn't make the thoughts follow one another as much as it filters out the ones that don't logically follow. Nature need only evolve such a filter in order to result in rational humans.

In short, you can accidentally come to believe a fact, but you cannot accidentally possess a rational insight that leads you to believe the fact.

Think about my example above. The filter evolved over millions of years. In that case, my filtered thoughts today are not random or accidental in your sense of the term. They are no more random than the color of fur on a zebra, or the killing instinct of a lion.

I reach a rational conclusion because my evolved filter eliminates the "insights" (guesses) that are non-rational. That is, my belief is justified by logic.

Chess programs can make moves that are mechanically aligned with strategic reflection. But unless such programs are conscious, obviously they cannot make moves that qualify as strategically reflective.

I don't see how this is relevant without begging the question. Chess programs are not reflective, because they don't think about their thinking. But reflection isn't central to the AfR is it? The AfR is an argument about causality, namely, "how does one end up with rational thought without our being caused to do so?" I have shown how there is a causal link from naturalism to rational thought. The AfR is not an argument about consciousness per se.

Finally, I want to attack the intuition that was the motivation for the AfR.

What do you regard as a rational conclusion? Rationality involves induction (assuming past experience is a guide to future experience), consistency-checking, and so on. Reflective rationality involves you examining your own steps to your conclusion. You recognize brute facts of observation, recognize past regularities, and recognize what an inconsistency looks like. So, after you reach a conclusion, you can state why you reached it, and declare it to be rational.

Deep Blue doesn't do this. It has neither the ability nor the need to waste CPU cycles checking itself. It's programmers do not ask it to question its own rationality. That's why Deep Blue is not reflective. Deep Blue might use Monte Carlo algorithms to make guesses that it later prunes for consistency, or make rote responses based on programmed rules. That is, it follows the rules a human might follow (if she only could), but it has no doubt about its own processing.

To date, we have only conceived of machines that are reflective and emotional, but we haven't built any (to speak of). Yet, we have every reason to believe we can do so, and no good reason to believe that we cannot. If the machine doubts its present inputs, it can randomly devise some test (which it filters for consistency) that confirms or falsifies its doubts. If it doubts its filter, it can use automata (deduction), and see if it gets a contradiction. Finally, if it doubts its inductive inferences, it can test its theories empirically.

IOW, I think that the AfR is implicitly an argument from incredulity.

 
At 7/29/2007 08:09:00 PM , Blogger Darek Barefoot said...

DL
I regret that I just don't have time to continue with the evolutionary/computational aspects of the discussion. Suffice it to say I disagree. I must limit myself to the original point.

>>My argument is merely that the AfR has no such power because, contrary to the AfR, there is a causal connection between laws of physics and mathematics and our reasoning ability.<<

The existence of some kind of causal connection between reason and the laws of physics is hardly proof that reason is a physical process. Is the causal connection "physical" in the ordinary sense of the term? And does this connection occur within a single causal context as naturalism requires? To say that physical objects/states and even the laws of physics obey the laws of logic amounts to saying that these objects and laws may be known rationally. Perhaps that must be assumed; science does assume it. But if anything that puts rationality in a special, priviledged position from the start. The only way to salvage physicalism is to claim that the rules of logic express themselves in nature exclusively through the laws of physics and bodies of rules that depend upon the laws of physics--that is why it is called "physicalism."

Science does not investigate empirically how the rules of logic cause the laws of physics to be the way they are, but it does investigate the brain and its chemistry. Thought undoubtedly depends in some measure on brain chemistry, but does it depend on it entirely? If thought is entirely dependent upon brain chemistry, then the rules according to which thought must proceed in order to be rational must be entirely dependent upon the rules of chemistry. There are rules for cooking food, rules for refining gasoline from crude oil, rules for treating municipal water, rules for the production of sugar by photosynthesis. In all these cases, there are conceivable changes in the rules of chemistry that would require changes in the derivative process rules. Well, there are rules for producing sound conclusions from premises in the mind/brain, too. Why are these different from those other cases?

Are chemical reactions things that can be understood rationally? Yes, that is what we mean by saying that they obey the laws of logic. But we are not here considering whether chemical reactions can be rationally understood. We are asking whether chemical reactions can rationally understand. If a series of chemical reactions is what an act of understanding is, then such an act is governed by rules of chemistry or by rules that depend upon the rules of chemistry. But such dependency is ruled out. Here is where the dilemma lies.

 
At 7/30/2007 07:27:00 PM , Blogger Doctor Logic said...

darek,

The existence of some kind of causal connection between reason and the laws of physics is hardly proof that reason is a physical process.

The burden of proof is yours, not mine. The AfR is intended to show that naturalism is incoherent. It fails.

But if anything that puts rationality in a special, priviledged position from the start.

It is in a privileged position from the start. The laws of rationality cannot be rationally proven, and must be assumed. The same is true for the dualist, BTW.

The only way to salvage physicalism is to claim that the rules of logic express themselves in nature exclusively through the laws of physics and bodies of rules that depend upon the laws of physics--that is why it is called "physicalism."

I'm not sure there's a problem with that. The laws of physics are consistent (non-contradictory). That makes them logical. Everything else could be a matter of physical representation.

In all these cases, there are conceivable changes in the rules of chemistry that would require changes in the derivative process rules. Well, there are rules for producing sound conclusions from premises in the mind/brain, too. Why are these different from those other cases?

They are different because logic requires only non-contradiction and identity. And you cannot have any possible laws without these. Consequently, there is no possible change to the laws of physics that could change the laws of logic/rationality. The laws might not be compatible with life or with machines that reason, but they cannot change the laws of rationality without ceasing to be laws at all.

That's why there is no dilemma.

 
At 7/31/2007 06:44:00 AM , Blogger Darek Barefoot said...

DL

>>They are different because logic requires only non-contradiction and identity. And you cannot have any possible laws without these.<<

You cannot have laws of physics without identity, right? Or laws of chemistry. Or rules of oil refining. All of them obey the laws of logic in the sense you are talking about. But my examples of dependency still hold for the interrelationships among these bodies of rules, don't they? And rational thought processes are still excluded from this type of dependency. Rational thinking doesn't just require that attendant chemical processes are logical the way all chemical processes are logical. Rational thinking requires recognition of the logical nature of one thought pattern as opposed to the illogic of alternates. Recognition. And deliberate adherence to the the logical as opposed to the illogical pattern.

>>Everything else could be a matter of physical representation<<

Chemical reactions lack the force of logical necessity by nearly universal consensus. Chemical A can interact with chemical B to produce chemical C--without logical necessity. But this chemical transformation can be used to represent a logical transaction among premises yielding a conclusion that does have the force of logical necessity. To repeat, interactions which lack logical necessity can represent those that have it. But you cannot turn around then and say that it's easy to see how chemical reactions can have the force of logical necessity because they can represent it!

Let's say there is a boy dribbling a basketball. Every time the ball rises his hand pushes it down again. The sun is casting a shadow of the boy and the ball against a wall. The shadow of the kid's hand appears to be "pushing" the shadow of the basketball. But a shadow cannot actually "push" another shadow. To talk about the shadow ball being "pushed" by the shadow hand is incoherent except in the context of real hands that can actually push basketballs as distinguished from shadows. Likewise, saying that a chemical transaction lacking logical necessity can represent a transaction possessing it is incoherent unless the kind of transaction being represented is distinguished from the merely representative one.

With the nature of representation we have just come around a track that we have already beaten flat in a previous exchange. You are welcome to the get the last word in and close out this one.

 
At 7/31/2007 01:51:00 PM , Blogger Doctor Logic said...

darek,

Okay, my last word on this thread.

The main problem here is equivocation regarding law, rule, force and necessity.

You regard rational thought as being directly caused by some force of rational thought. However, it is actually the case that thoughts are merely categorized as rational when they meet certain criteria. IOW, the rationality of a thought is necessary only for it to be categorized as rational.

Human laws of rational thought are like the rules of baseball. The players on a baseball team do not play according to the rules because the rules directly cause or force them to do so. There is no "force of baseball" that acts to make people play baseball according to the MLB rules. Rather, the players' actions are categorized as legal or illegal according to the way they play the game. A player who breaks the rules is playing illegally. The real reason that players play legally (or at all) is that there are indirect consequences for meeting or breaking the rules, and the players know this. Playing legally is necessary only to have played legally.

Similarly, human thought patterns can be categorized as rational or irrational, but it is NOT the case that some "force of rationality" directly compels us to think rationally. Rather, there are benefits to thinking rationally, and penalties for thinking irrationally, all due to the fact that every system governed by natural laws must be logical.

Both baseball and rational thought can be contrasted with the laws (or, I should say, forces) of physics. Physics relates to inviolable forces, e.g., I cannot pitch the ball legally if you disconnect my tendons and muscles from my bones. And if my muscles and tendons remain connected, I still might not pitch the ball legally. That's because legal and illegal play are categories of physical possibility, and not necessities. The laws of physics alone are necessary, but not sufficient for a person to play baseball. However, some configurations of matter and energy (players, fields, equipment, etc) are sufficient for legal play.

My thinking that 2 + 2 = 4 is necessary only for my thoughts to be categorized as rational. Yet my thoughts are not necessarily rational in this universe. The laws of physics alone are necessary for me to think rationally, but not sufficient. What is (usually) sufficient is the particular configuration of my brain which makes my thoughts, upon reflection, recognizable as rational.

So your "complaint" is that physical minds must necessarily obey physical laws, but physical law is not sufficient for rationality of any given system. However, some systems do have a configuration that is sufficient for rational thought. Indeed most people are configured sufficiently well for rational thought at least some of the time. And that's all that's required for consistency with observation. So you have no argument against naturalism in general.

If your argument showed that rational thought was always impossible under physicalism, it might have some force, but it doesn't show that.

Maybe you're saying that 2 + 2 = 4 is a necessary truth. It certainly is, but only if you first assume the rules of rationality. However, that has nothing at all to do with whether minds are material or not. A physicalist will certainly agree that 2 + 2 = 4 is a necessary truth under the rules of rational thinking because the necessary truth of mathematics is one of the bases of physics and rational thought. However, no one seriously thinks that we are compelled to think rationally by forces of rationality any more than they think we're compelled to play legal baseball by forces of baseball.

Moreover, I can look at necessary theorems in baseball. Under the rules of baseball, it is necessary that a hit into left field that is not caught and which results in a man on third running home earns a point on the scoreboard. This is a necessary truth under the rules of baseball (and rationality). And we can examine a real life play to see if it matches this theorem. However, we would never argue that this theorem stemming from the axioms of baseball is what forced a player to to hit the ball into left field and win a point. No, the play would be necessarily categorized as legally winning a point according to the rules, and that is all. At most, we would say that the player's awareness that he would be rewarded according to this categorization is what caused him to swing his bat. Not the same thing as saying that he was forced to swing by the rules of baseball.

The difference between rules of rational thought and the rules of baseball is that rational thought has advantages in any lawful universe with any history. Whereas the advantages of playing legal baseball depend on accidents of human history. On an alien planet, rational thought should always pay off, but playing legal baseball may have adverse consequences.

 

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