From Victor Reppert:
I am convinced that a broadly materialist view of the world must possess three essential features.
First, for a worldview to be materialistic, there must be a mechanistic base level.
Second, the level of basic physics must be causally closed.
Third, whatever is not physical, at least if it is in space and time, must supervene on the physical.This understanding of a broadly materialistic worldview is not a tendentiously defined form of reductionism; it is what most people who would regard themselves as being in the broadly materialist camp would agree with, a sort of “minimal materialism.”
To the atheists:
Some of you know you’re materialists, some of you suspect it, others try to deny it or don’t like to be identified as such. But if you’re an atheist what else do you have?
Entirely my fault I’m sure. Really I just wanted to offer a clear presentation of what it might mean to say someone is a materialist, and explore possible objections to Reppert’s three essential features.
I threw the whole atheism thing in gratis. 🙂
But it seems to me they are connected.
This thread is a follow up to a couple earlier threads here in which the subject of materialism came up. Elizabeth doesn’t care for the word and thinks it’s basically meaningless. Even the link given by fG takes that stance:
But it’s the edge cases that can make or break a thread in terms of interest. So I didn’t want to make it too narrow. Someone might say, I’m an atheist but I’m not a materialist. Or someone else might say, I am a materialist, but I am not an atheist.
I found your question about what a Christian might believe interesting. It made me think. To me Christian theism would differ mainly around the second element.
Hmmmm. I think one would have to be pantheist, and also hold that everything that is mental is also physical to be a theistical materialist.
But maybe there are some other possibilities that have eluded me.
I guess the difficulty I am having with your question is what would it even mean for physical entities to behave irrationally, unintelligibly, abnormally, purposelessly, chaotically? I guess a Christian could believe that there is no purpose at that level of reality but why on earth would they, or better yet, could they coherently claim to?
But basic physics is nothing if not rational and intelligible and normative. (Not saying there’s consciousness at that level.)
I think this is where I part ways with KN wrt teleology. He finds purposiveness in living systems and I find it at the most fundamental levels of physics and chemistry.
So perhaps your question is whether an additional premise is required for the Christian view.
God upholds the existence of all contingent beings and makes them intelligible and provides them with purpose. Then your question might be, must a Christian believe this? Am I getting closer?
Mung,
This all depends on what’s meant by “materialism” or “physicalism,” I think. A physicalist might be somebody who holds that everything in the universe is a physical object or process. But s/he might also hold that some of the physical objects or processes in the world are also mental. Such a one might be a property dualist, for example.
So materialists need not deny the mental, although some do–or at least seem to.
I think it is important in these questions to define not just what something is, but more importantly a way of distinguishing the two. What sort of event would be allowable in physical but not non-physical worlds? Often times this is the point where there is contention. Much of what was previously considered non-physical is now part of physics. Does this mean that physics is non-physical, or that our previous conception of physical was wrong? How does one decide, a priori, what counts as a physical vs. non-physical cause? I have my own answer, but I think first it is important to float this out there because I think this is more foundational than the arguments we have about it.
Yes indeed. Unless I am clear what the questioner’s answer is to this, I cannot easily answer the question as to whether I am a materialist/physicalist or not.
If information by which I mean pattern or configuration counts as what is physical then I would count myself a physicalist o guess.
I agree that causal closure of physics is an important dimension to characterizing positions.
I understand that all Christians would agree that God intervenes in the world in ways inconsistent with physics. But there would seem to be a large range to that position: everything from the deist Christian who would say just once at the start to those Christian footballers who pray for personal success at the start of each football game.
I think you’d find the same sort of variations in positions on causal closure of physics and how that speaks to physicalism and materialism. For example:
– What is the difference between materialism and physicalism? I personally don’t use “materialism” at all to avoid confusion, some use the terms as synonyms, some see them as different
– what does it mean for an event/entity to be physical? What does the position say to Hempel’s dillemma (which johnnyb alludes to below)
– do causes supervene? That is, do the causal powers of emergent entities supervene on the causal powers of their physical realizers? Or are emergent causes as real as base physical causes? If so, how is overdetermination addressed? Or does the concept of supervening not apply at all, in which as all causes endorsed by science have equal claim to reality (perhaps none!)
In general, I think there are too many variations and combinations to make possible your goal to “Stake out a position to which I (and others) can refer to just in case that I call someone here a materialist”. Better to have an overall understanding of the pros and cons of each major position and to seek clarification of where someone stands with regards to the issues listed above, plus others he or she thinks are relevant.
Hempel’s Dilemma
I’d probably start from a minimalist position: explanations must not postulate anything inconsistent with our best physics. But I’d add a fallibilist proviso: it is possible that our best physics can change, so I’d look at any particular issue on its individual merits. In doing so I’d take a Bayesian approach: my prior for explanations inconsistent with current physics would depend on the scientific consensus regarding the reliability of the relevant physics.
That is just about explanations being consistent with physics. The issue of whether science tells us anything about ontology/what is real has been explored many times on TSZ; probably too far off topic to revisit here.
I’m interested in your ideas.
I was thinking in terms of extrinsic purpose versus intrinsic purpose.
One approach to purpose in evolution is teleonomy. Roughly that there is no purpose intrinsic to mechanisms in living organisms; rather any purpose is extrinsic in the sense that it results from evolution. I’m excluding purposes at the whole agent level. (KN does not believe extrinsic purpose is real purpose).
Can we apply the same idea to physics? Reppert can be interpreted as saying there is no intrinsic purpose in fundamental physics. Perhaps a Christian could accept that but add that God endows physics with an extrinsic purpose; that is, the purpose in physical entities comes from God. Both Reppert and a Christian could still agree that people as whole agents have intrinsic purposes.
I think that norms only apply if wrong choices can be made.
Fundamental physical entities can be said to obey the laws of science, but they can never act wrongly in doing so. So they do not act in a way that norms apply to the entities themselves.
Norms apply to (eg) rational or moral choices because such choices can be wrong.
So norms might apply to what we calculate entities will do, but not to the entities themselves.
BruceS –
On the “modern physics” view, there would be no rational reason to be a physicalist today because physics provides no explanation of how consciousness comes about physically – not just that it is unsolved, but even the terms of discussion do not appear amenable to conscious activity.
The way i distinguish them is being calculable vs non-calculable. I don’t know that this is a be-all and end-all way to do it, but at least it makes an understandable and usable distinction.
I defend and make use of that definition in this paper on the subject –
http://www.blythinstitute.org/images/data/attachments/0000/0041/bartlett1.pdf
Thanks for posting that. It’s is a very good question, and is, as Bruce said, connected with (if not identical to) Hempel’s Dilemma. I don’t myself think that it’s possible to define “physicalism” without appeals to methodology (i.e., successful investigation in what we call “the physical sciences”).
I’ve noted before that Sondheim told Rorem that, ultimately, the only way to distinguish operas from musicals is to say something like “operas take place in opera houses.” That, like, “physical objects and processes are what physicists investigate” seems a cheat. And if the physicists maintain that they investigate EVERYTHING, it seems to put non-physicalists in a difficult position. They have to say something like “Well you try, anyhow–but until you succeed in explaining X and Y, you’re missing those things in your itemization of everything in the world.”
But “explain” and “succeed” are themselves quite difficult to define.
Anyhow, great post, and welcome to the site.
Physics doesn’ t but I suggest that neuroscience does. Physics is too fundamental. Consciousness by which I mean the capacity to be aware of aspects of the world and possibly to intentionally act within it, inheres in the configuration of fundamental entities not in their bases properties as it were.
That’s an interesting hypothesis. Thanks.
Well, we’ll have to disagree on that.
However, I do agree there is intuitive appeal to “explanatory gap” arguments or arguments that science cannot explain first person perspective.
Whether that intuition is justified is an open, empirical question, IMO.
Again, I have not read this in detail, but using the halting problem to show humans cognition cannot be computable sounds similar to, and perhaps even equivalent to, using Godel’s results to show human cognition must transcend finitist mathematics.
But that argument is general considered to fail. (although I recognize some experts like Penrose don’t agree). How does your argument differ?
As I understand the Turing Oracle argument, you are saying that perhaps minds can solve Halting Problems by using something like Turing Oracles, and since best evidence is that Turing Oracles are not physically possible, we can conclude that the mind must be non-physical. Is that fair, or have I butchered your argument by not reading in detail.
ETA: Scott Aaronson has a nice paper on Godel’s results, Penrose’s claims, Turing Oracles, and human cognition.
AFAIK, the halting problem and Godel’s Incompleteness results are two different ways of capturing the same idea. But I am not a mathematician. However, Scott A is, and he discusses the close relationship here.
I am. And I pretty much agree with you, including this part: “But that argument is general considered to fail.”
I know I don’t follow any of the technical info, but I’m pretty sure I understand this part:
And now I’m in love with Scott Aaronson. 🙂
Me too, for exactly the same passage!
A few quick notes.
1) Most of the time, the reasons that Godel arguments tend to fail are either (a) it is assumed that the brain is a machine, machines can’t solve Godel problems, therefore the brain can’t either, or, (b) brains aren’t perfect oracles for Godelian problems, therefore the argument fails.
Now, it would be a better argument for the materialists if the materialists can show that computers are as good or better than humans at solving Godelian-type problems. However, despite a century of research, they still are not. Humans still do much better at these problems, while computers all but can’t approach them. While I wasn’t arguing for it as the end-all, be-all solution to the problem, in my paper I suggested a more limited oracle which humans had partial access to. That is, rather than a general oracle for solving halting problems, humans have an “axiom” oracle. Let’s say, for instance, that there are a set of axioms (I call them bottom-up axioms) which can be built up for solving a problem (NOTE – I understand that the idea of bottom-up axioms is not a standard idea in mathematics, and would probably require an entire career to develop; nonetheless, please bear with me as a direction rather than a destination). My suggestion is that these axioms are somewhat orderable, or at least have a number of precursor axioms. My suggestion is that, given a problem P, if you have a set of axioms A, which contain all of the axioms but one, the mind is able to generate (though not perfectly) the single missing axiom. This explains both the way that humans appear super-computational, but also the way that we often have simultaneous discoveries in science – both how humans are creative and how the creative process builds from previous creative processes.
Now, the main emphasis of the paper is not that particular modeling of the mind (though I think it a good one that deserves some consideration), but rather that it has been commonly thought that if something is non-physical that means it is not amenable to modeling. My primary point in the paper is that mathematics already has the types of tools needed to model non-physical processes. They aren’t predictable in the normal sense, but they can be described in interesting ways (much like we can describe but not predict the outcome of a random number generator).
So, whether you like my model of the mind or not, the primary goal of the paper is to demonstrate to both physicalists and non-physicalists that having a non-physical conception doesn’t necessarily imply that there is no usable model. I have seen some people argue for non-computational cognitive activity using Godelian arguments, but fall short of *making use* of that aspect.
hotshoe_one – “The obvious response is equally old: “what makes you so sure that it doesn’t feel like anything to be a computer?””
The problem with this response is that it misses the point. It may feel like something to be a computer. However, if such a feeling-like were physical, shouldn’t physics tell us what that feeling is?
Why would you think that? Can physics predict the properties of water from the properties of hydrogen and the properties of oxygen?
No, the computer would tell you.
That actually isn’t a joke 🙂
Physics can’t tell me how you are feeling, but you can, by virtue not only of the physics that govern the particles of your body, but by the configuration of them as you, an organism, with a brain that subserves the capacity to feel and report your feelings.
Having said, that, if we want to build feeling-things, we will start, IMO, with robots, and probably let them largely evolve.
“Why would you think that? Can physics predict the properties of water from the properties of hydrogen and the properties of oxygen?”
I would hope that would at least be a goal of physics, and that someone would have some idea of a process to go about it. If not, then I have been holding physics in much too high esteem for my whole life. If physics is this bad at describing basic properties, perhaps then the question should not be whether physicalism is true, but rather if physics needs rethinking in terms of the spiritual rather than the physical.
“No, the computer would tell you.”
How would you, epistemologically, establish that the computer was correctly telling you its feelings?
In exactly the same way that I would establish that you are correctly telling us your feelings. That is to say, no way at all. That’s why we say it is subjective.
USE blockquotes, johnnyb.
It’s rude not to.
It makes your communication with us unclear, which is a bad thing unless you have some reason to deliberately wish to be unclear.
And it’s way too easy to use blockquoting for you to have any other excuse not to. You are definitely smart enough to figure it out.
If you need help, be brave enough to ask.
Don’t act rude.
Same method as I’d use with you – from its behaviour.
But let me be clear: I don’t think our current generation of computers have anything resembling feelings. I think the nearest we’ve got is with robots. And once we’ve got robots who can behave like people with feelings I will have no difficulty in saying that they have feelings. Which is a long-winded way of saying that I think that p-zombies are a nonsense 🙂
There is no rule at TSZ that you have to use blockquotes.
But we do have a neat plug-in (I think it’s a plug in) that lets you select part of someone’s post, and include it in your reply, and it puts in a link to the original.
Each of us come to identity ourselves as having the beliefs and desires we do as a result of our ongoing dialogical encounters with each other — a process that, for each of us, begins as infants being cared for by others. We are socialized into taking ourselves as subjects. If a synthetic being with an artificial mind were sufficiently complicated that it could participate in our discursive activity, it would have beliefs and desires as well.
To the person who says, “it can’t really have beliefs and desires because we can look at the logic gates!”, one might as well respond, “well, you can’t really have beliefs and desires because we can look at your synapses!”
I doubt that complete knowledge of the properties of hydrogen and oxygen would allow one to predict any or all of the properties of water — but if you understand the properties of water, and you also understand the properties of hydrogen and oxygen, physics does allow you to explain the former in terms of the latter.
The problem here, however, is that explaining the properties of water in terms of the properties of hydrogen and oxygen (and those properties in terms of the properties of electron orbitals and atomic nuclei, etc.) isn’t really the same kind of thing as trying to explain phenomenology in terms of cognitive and affective neuroscience. That’s the point Nagel is making in “What is like to be a bat?”, and he is correct. (There’s some quibbling over the details.)
The explanatory gap between the first-person perspective (subjectivity, consciousness, the content of phenomenological descriptions) and the third-person perspective (objects and their publicly available behavior, functioning, mechanisms, etc.) is a real gap. It cannot be made to disappear. The question is, why is there an explanatory gap, and what is the significance of that gap?
How do you know that it cannot be made to disappear?
I’ve posted a link Price’s Should We Expect To Feel As If We Understand Consciousness?
But it is worth a repost to share this summary of his argument: The gap, dear KN, lies not in our explanations but in ourselves.
Sure, there’s no rule.
But it’s the local culture – and I warrant it’s the culture anywhere that the architecture allows it – because it makes communication immediately better and more clear.
Refusing to learn/use that simple skill – especially when, as you say, the site does half the work already with the “quote in reply” feature – is an unattractive stance.
It’s either rude, or stupid, or both, or perhaps something else I haven’t identified. But since we know johnnyb isn’t stupid …
It’s no different from going to someone’s home and noticing that they take off their shoes by the door and that there’s a box there labeled “guest slippers”. There doesn’t have to be a rule. It’s just polite to pay attention and go along, and it’s especially smart to be polite when it costs one nothing while potentially gaining one something as well (be that more clear communication or more relaxed feet).
I’ll delete this and repost it in Moderation if you think I should, or you can feel free to move it if that seems right. Or I could just promise to shut up about this particular issue re this particular poster. I promise. Sorry for the derail.
Indeed. Chemistry is not reducible to physics. But it’s not the fault of physics that it’s been held in high esteem.
It seems to me at least that Reppert avoids a lot of the issues that have been raised.
The objections I am familiar with to applying Godel’s results to the question of computational brains turn on the issue of consistency of the system. Do humans have some special, non-computational ability to prove Godel-sentences? Scott Aaronson notes two points:
In other words, why assume an computational human brain has to be consistent? Or how can we be sure that humans really can “see” system consistency needed to “see” Godel-type sentence in the general case.
Yes, computers today are limited. But that proves nothing about whether the human brain uses computation.
So you are saying that there exist models for non-physical brains. Fair enough. But do we need them? We first have to show brain processes are not consistent with physics. Which is more than showing they are not computational. And even that is still an open question.
Others have responded to your points on feelings and computers. I’d only emphasize that very few, probably no, physicalists would expect a cogent explanation of subjectivity in terms of physics; explanations would be likely in some combination of neuroscience and psychology.
Questions of ontology are different, of course.
Is there any particular reason for this post?
From my perspective, the problem is the one hinted at by keiths. Gödel’s incompleteness theorem is a result about formal system. If it has any relevance to physics, then that is far from obvious. As far as we know, the cosmos is not a formal system. And if it is a formal system, then we don’t know the rules of the game.
Likewise, the halting problem for computers is very much a theoretical problem. It doesn’t have any obvious application to actual computers. The halting problem, if described in terms of computer rather than Turing machines, is a problem for computers with an infinite amount of memory and that are so perfectly reliable that they never crash (not even when the power fails). The role of infinity is an important part of the proof.
The OP had just bullet points. I’m filling in some of the details. No particular reason other than his second was next up at the time. Next up will be more on Reppert’s third essential feature of materialism.
It seems like there might be some friction between the Laplacian determinism reflected in that quote and quantum mechanics.
Right. It’s the relationship between the mental and the physical that matters. People can believe they have a mental life, but if they think the mental is something that only emerges from physical events in a big brain, they might be a materialist.
Interesting. I honestly don’t read it the same way. He doesn’t say you would actually be able to predict where the particles will be in the future.
Yeah, I read it again: you’re probably right.
I thought your quote might go with this somehow.
So I’m still wondering what particular issues that have been raised you think Reppert addresses and how you think he addresses them.
Sure, valid points.
But I read johnnyb as referring to the argument that Lucas made to the effect that the mind cannot be computational, ie a formal system, because it can see a proof of the Godel sentence.
The points about consistency, possibly mangled by me, are the counterarguments I’ve seen to Lucas’s argument.
I think johhnyb might want to use that argument to buttress a case for non-physicality of the mind, so physically-based failures like some you refer to might be ignorable for him.
Victor Reppert:
Not all “materialists” accept the concept of “supervening on the physical”. But many do. But then when you ask those what that supervening means and what physical means, you find there is not a single answer to either question.
So your OP quest remains quixotic, IMO.
What you think is “materialism” is actually a misunderstood Strawman based on an exaggeration of the significance of something that’s not even a theory and barely counts as an observation:
Things are made of stuff.
I’m not talking about atomic theory or the periodic table, those are actual theories that are actually scientifically interesting and they’re not just completely stupid. No, you have somehow turned “all objects and living things are made of substances” into an all-encompassing philosophy and I’ve seen you guys try to use it to argue against logic itself.