MUH is not incompatible with physicalism (it just reframes what physical things are), and if physicalism is compatible with phenomenal consciousness (which it is; philosophers like Galen Strawson actually argue panpsychism about phenomenal consciousness is entailed by physicalism) and MUH encapsulates a physical world then it also encapsulates phenomenal consciousness.

Why would MUH prima facie be incompatible with phenomenal consciousness?

This may be relevant:
https://www.youtube.com/watch?v=qTx98PUW6lE

I didn't mean to imply that MUH is incompatible with physicalism. Only that physicalists have typically assumed that there is more to the existence of the universe than just the fact that the math to describe it exists. E.g., it's usually considered that the existence of the universe and the particular way that it is, is contingent. While if MUH is true, then it is necessary instead. (Of course, if you buy into Lewis' Modal Realism, then everything is really necessary too. But in my journeys, I haven't noticed many philosophers who champion Modal Realism.)

As for why MUH would be incompatible with phenomenal consciousness, as I already stated, I believe it to be a category mistake to assert that phenomenal consciousness is purely mathematical. Clearly Tegmark disagrees with me. I suspect, however, that most philosophers would agree with me. Only I don't know for sure, since I've never seen a professional philosopher mention MUH. (Not that I'd really know where to look. I haven't studied philosophy seriously for quite some time now.)

|>ouglas

That talk looks to be very interesting! But does it have anything at all to do with MUH?

Your question ought to be addressed to professional philosophers. It is futile to ask dilettantes what a professional thinks. It's a little like "what do you think Jesus thinks" on some certain topic.

Only Jesus knew what he thought, and only a professional philospher is in a postiion to reveal what he or she thinks. As a professional, however, will charge you a fee for this. Otherwise he or she sinks to the level of an amateur.

I’m a mathematicist (what Tegmark’s MUH is a form of) and a modal realist and a physicalist and a panpsychist, myself. As I understand modal realism, it doesn’t so much imply that everything is necessary, because necessary means true at all possible worlds, and just because all possible worlds exist doesn’t mean anything in particular is true at each of them. The same distinction extends to the other mathematical structures of a mathematical multiverse; in fact I like to draw an analogy between the two and say that just as in modal realism “actual” is indexical (the only thing that makes this world the actual world is it’s the one we’re in), likewise “concrete” is indexical (the only thing that makes this mathematical structure “concrete reality” is that it’s the one we’re part of).

I also think that the mathematical nature of the universe lends itself very nicely to a panpsychist view of phenomenal consciousness. If everything is mathematics then everything is basically information signals moving between mathematical functions, in a way very similar to Whitehead’s process philosophy’s ontology, and on the account of physicalist panpsychists like Strawson, to be phenomenally conscious is just to be on the receiving end of a physical interaction, which is a lot easier to take in if those interactions are already being seen as just transmissions of information. Mathematical structures are very “mind-like” in a loose way, much more than the conventional lay view of physical structures as being made of little bits of dumb rock.

Who cares what philosophers think? What of professional mathematicians?

Well, many think of MUH in the same way they think of ZFC: Not a lot. :cool:

Where can I do that?

Btw, I didn't ask what people's opinions here are. I was trying to ask if anyone knows of any published debate amongst professional philosophers on the subject.

Well, professional philosophers actually work right across the street from where I work, and sometimes I have gone and bugged them. But since they're rather busy, they're often not so chatty. Unless I sit in on a class, which I could do were I feeling very motivated.

They don't actually charge, and I've yet to have one object to letting me sit in on a class for free. In fact, in one class, the professor was even willing to grade my papers, even though I wasn't paying. (Or rather assign the job to his graduate student.)

I suppose I might also write to David Chalmers to ask if he can point me at any literature. He might actually answer me, since I have a Philosophy degree from MIT and wrote a graduate-level term paper on a published critique of his 2Dism.

|>ouglas

Well, I have a degree in Philsophy, so I guess I have an interest and a bias.

|>ouglas

Do professional philosophers ever debate over Tegmark's MUH? Or is it not really on their radar? — Douglas Alan

It's a separate department, down the hall, to the left, along the corridor, marked 'Physics'.

But seriously - I think most philosophers are extremely reticent when it comes to these matters, unless they also have degrees in mathematical physics (which some do). I mean, anyone can wax philosophical about quantum strangeness - I've been known to do that myself! - but if they're, as you say, 'professional', then presumably they have a reputation to look after and don't want to rush in where others might withhold judgement.

Personally, from what I've read about Tegmark's books, most reviewers take his mathematical speculation about the various levels of multiverse with a pretty major grain of salt. I think the interesting philosophical question that should be asked is: what difference does it make if it were true?

(There are some physicists who are philosophically literate - Bernard D'Espagnat is one. Werner Heisenberg's 'on physics and philosophy' is still a pretty good read. I've heard that Lee Smolin is pretty well-regarded in philosophy of physics, and also Tim Maudlin. Oh, and Paul Davies on the popular philosophy level. Oh, and BrIan Greene - I seem to remember his last book was specifically about multiverses.)

Well, yes, I actually have a degree in Philosophy, so I understand this. It's just that being very precise is very verbose. Things that I might try to state in two sentences here, I might devote 5 pages to if I were writing a Philosophy paper.

Modal realism, if you accept it, removes any mystery about why the contingent facts are what they are. Forget about modal realism for a moment and then ponder on how it would be much more elegant (or so it seems to me) if all facts were necessary and no facts were contingent. Modal realism accomplishes this goal. It removes the mystery of why things are they way they are and not some other way, and provides the same elegance as if all contingent facts were necessary. I.e., it's necessary that all possibly true facts that are contingently false in our world are true in some real world. The mystery of why the contingent facts are what they are reduces simply to which world we happen to be located in. And there's no mystery in that.

MUH accomplishes the same goal, of course, for similar reasons. I.e., they are somewhat similar theses. Modal realism is less constrained, however, because in modal realism there are worlds with things in them that can't be described by mathematics.

Well, I really should devote another five pages to the above, but I hope I'm being clear enough so that I don't have to.


We're just going to have to disagree on this. For me, it's a Moorean fact that real phenomenal consciousness cannot arise from nothing but pure math.

I understand that some people are going to disagree with this. E.g., Max Tegmark, my friend Greg, who's a professional mathematician at an Ivy League university, you, etc. On the other hand, I suspect that the vast majority of professional philosophers would agree with me on this. If they think about anything like MUH at all, that is. They certainly didn't the last time I chatted with any professional philosophers. But at the time Tegmark hadn't published an entire book on the subject.

I did once go to a lecture at MIT given by a philosophical logician, and I tried to explain MUH to him after the talk, I was having a hard time until I described it as "radical Platonism". Then he was very receptive. So maybe there's one professional philosopher who would endorse MUH. On the other hand, he seemed more of a logician than the kind of philosopher who would OCD on why there's anything like the feeling of redness in the universe.

Back before Tegmark's book, I also tried to explain MUH to a professional philosopher, and his only reaction was something along the lines of, "Well, he seems to be suffering from some profound misconceptions." But then he immediately wanted to extricate himself from the conversation without providing any more reasoning.

|>ouglas

If there is existing Philosophical literature that addresses any of this, I would be greatly interested — Douglas Alan

Here you go:

https://scholar.google.com/scholar?&cites=6942634181980308378

These are the Google Scholar cites for his original paper The Mathematical Universe (2008). And these are the cites for the book Our Mathematical Universe (2014):

https://scholar.google.com/scholar?cites=3221947870983275224

You can add to these the cites for the 2003 paper Parallel Universes, which is perhaps the first publication where he broached the idea (the "mathematical universe" would be what he calls "Level IV universe" in that paper):

https://scholar.google.com/scholar?cites=11792485456341973819

Some of the links are spurious, and many cites are not from philosophical literature, but you can still find what you are looking for in these three lists. For example, Ladyman discusses Tegmark's view in his SEP entry on Structural Realism.


By the way, you can include a quote from someone's post by selecting the text and clicking on the quote prompt.

I actually have a degree in Philosophy — Douglas Alan

Welcome to the club. :-) You should post in this poll thread if you haven't already. (Also I could use some more educated eyes of at this project if you have some time).

The mystery of why the contingent facts are what they are reduces simply to which world we happen to be located in. And there's no mystery in that. — Douglas Alan

Okay, it wasn't clear that that's what you meant before. Sounded more like you just didn't understand modal realism (which you clearly do, now).

We're just going to have to disagree on this. For me, it's a Moorean fact that real phenomenal consciousness cannot arise from nothing but pure math. — Douglas Alan

I'm guessing you're referring to something like the Open Question Argument here? I'm a big fan of that line of argument in its original use but I've never heard that applied to the topic of phenomenal consciousness before, only moral semantics. I don't see how it could clearly apply to the topic of phenomenal consciousness either. Moral questions are asking a different kind of thing to which no descriptive fact can be an answer, so giving a descriptive answer to a question of prescription is a non-sequitur that just leaves open the original question entirely. ("Is it good to save people from torture?" - "It decreases their suffering." - "And is that good?") I don't see how something like that applies to phenomenal consciousness. I'm guessing you're thinking something along the lines of how no functional account of the objective behavior of a thing can tell us anything about whether it has a subjective experience; that is a point I've made here over and over again, and used as a crucial part of an argument for panpsychism. But just because an account of function doesn't account for experience doesn't necessarily require there to be, for example, something non-physical to have the experience, or something non-mathematical in this case.

Here's a very loose argument (I'm winding down for bed and therefore lazy) for why mathematicism actually meshes better with the existence of phenomenal consciousness than a more conventional kind of physicalism: mathematical stuff is easily understood as mental stuff, as ideas in the mind. (Your comparison to Platonism below makes this clear). If the physical world is made up of math, and human minds are instantiated in physical structures, it's much less weird that those physical structures should be able to do mental things, given that they're actually made of mental stuff to begin with. In the stricter, less dualistic terms that I would prefer to think of it, if everything is informational at its base, of a kind akin to what thoughts are composed of, so physical structures are informational structures, physical processes are informational processes, then it really shouldn't seem so weird that some of those informational processes should constitute thought processes as we're familiar with them. It would be weird if only human brains had anything mind-like about them when everything was made up out of the same mind-stuff... but panpsychism gets around that, by saying yeah, everything is kinda mind-like, everything has something like the phenomenal consciousness that we do, some kind of subjective experience or another, most of it radically less complex and interesting than ours, but the more like us they are in function, the more like ours is their subjective experience too.

I tried to explain MUH to him after the talk, I was having a hard time until I described it as "radical Platonism". — Douglas Alan

"Mathematicism" seems to be the usual term used in philosophy circles, so maybe that would get more people's comprehension. And IMO it's more Pythagorean than Platonic, though I've heard it described as "radical Platonism" too. But I don't like that: I'm strongly anti-Platonist, as he separates the ideal from the physical, and debases the physical as not living up to the ideal, while I don't see mathematicism (whether ancient Pythagorean or modern Tegmarkian) as doing that. It's much like how I'm strongly anti-dualist but partial to something like (a more Berkeleyan, not Platonic) idealism, because it doesn't say that the mental is something apart from the physical, but that the physical is subsumed within the mental; likewise, mathematicism, unlike Platonism, doesn't separate the mathematical or ideal from the physical, but subsumes the physical within it.

You can add to these the cites for the 2003 paper Parallel Universes, which is perhaps the first publication where he broached the idea (the "mathematical universe" would be what he calls "Level IV universe" in that paper): — SophistiCat

Weird, I could swear that that paper was from 2002 or earlier, as I clearly remember referencing it in a college paper I wrote in early 2002.

But in my journeys, I haven't noticed many philosophers who champion Modal Realism. — Douglas Alan

At a guess, there are probably even fewer philosophers who accept MUH (which Tegmark himself readily acknowledges), and Tegmark is probably its only champion so far.

As for why MUH would be incompatible with phenomenal consciousness, as I already stated, I believe it to be a category mistake to assert that phenomenal consciousness is purely mathematical. Clearly Tegmark disagrees with me. I suspect, however, that most philosophers would agree with me. — Douglas Alan

As I said, most philosophers would share your reservations about MUH, but not necessarily for that reason (the more common criticisms would be the same ones that are leveled against structural realism). Some, like Dennett, just don't accord "phenomenal consciousness" the kind of autonomous metaphysical status that philosophers like Searle, Nagel and Chalmers think it ought to have.

Weird, I could swear that that paper was from 2002 or earlier, as I clearly remember referencing it in a college paper I wrote in early 2002. — Pfhorrest

You may have read an arXiv preprint. Ladyman also cites an earlier date for the Mathematical Universe paper, following its arXiv entry.

I feel like I saw it in some kind of popular science publication. I don't think I was even aware of arXiv yet back then, if it even existed. But my memory of that time is pretty fuzzy now, so I could be wrong about all of this.

Where can I do that?

Btw, I didn't ask what people's opinions here are. I was trying to ask if anyone knows of any published debate amongst professional philosophers on the subject.

Well, professional philosophers actually work right across the street from where I work, and sometimes I have gone and bugged them. But since they're rather busy, they're often not so chatty. Unless I sit in on a class, which I could do were I feeling very motivated.

They don't actually charge, and I've yet to have one object to letting me sit in on a class for free. In fact, in one class, the professor was even willing to grade my papers, even though I wasn't paying. (Or rather assign the job to his graduate student.)

I suppose I might also write to David Chalmers to ask if he can point me at any literature. He might actually answer me, since I have a Philosophy degree from MIT and wrote a graduate-level term paper on a published critique of his 2Dism. — Douglas Alan

You actually did, what you deny you did. Assuming we are not professional philosophers, we can only have OPINIONs on what the opinions of professional philosophers are. If we KNEW (beyond mere opinion) what professional philosophers think, we would have the same knowledge as professional philosophers, which would only be possible if we were professional philosophers.

You may have wanted to ask what you iterate in the italic, but you did not try to ask that.

-------

The rest of your post is enviable for me. I wish I had access to philosophy classes and more importantly, debates in words or voicing my opinion in words. I took two philosophy classes, beginners' level, at universities, and got the possible highest mark in both (A+). I attended two series of lectures in beginning levels of classes back in another city, auditing, without paying, both of which ended in a scandal.

I think of myself as a born philosopher, but without any sizeable education in it. My mind is set up for it, but there is no nurturing.

I appreciate other venues are available for me to educate myself: free lectures on the Internet, Youtube videos, Wikipedia. I admit I don't take part in those because I feel lazy and listless. I can't get motivated, and I don't regret that: Life is not to be lived in fear and loathing, life is not to be lived in counting the ways in which I "ought", but instead just do it, go for it, leave the guilt and scolding others throw at me behind. And most importantly, leave the guilt and scolding I, myself, throw at myself, behind.

Platonism, (...) separate(s) the mathematical or ideal from the physical, — Pfhorrest

I thought that the very idea of Plato's ideals was that they were actually existing, physical things, that embodied the perfect, everlasting, structure of what we only imitate in our building of objects in our lives.

At least this is what I got out of the Republic. I may be wrong.

Plato does think they are actually existing, but in some different realm from the physical things that exist in space and time, sometimes half-jokingly called "Plato's heaven". In contrast, mathematicism like Tegmark's essentially says that "Plato's heaven" is all that exists, and space and time as we know them are features of the mathematical structure (in that "heaven") of which we are a part. So there's not the realm of space and time that we experience and then separately the realm of ideas: there's just the ideas, and space and time and everything in them that we experience (including ourselves) are ideas.

Thanks. Very interesting. I hope you won't take offence, but I don't buy this. I am an existentialist; I believe that existence exists. Cogito ergo sum. I exist. What my matter or consistency, or state, protoplasm, proteins, or essence is, who knows. But I exist, and that's good enough for me. No math can disprove that for me.

Plato does think they are actually existing, but in some different realm from the physical things that exist in space and time, — Pfhorrest

Can you name a page number reference on an easily accessible copy on the Internet to this notion in the book? I am not challenging you, I am challenging myself.

I know Plato insists they are everlasting, and perfect. But I don't recall them existing in world where everything is everlasting and perfect. But then again, my memory is crappolo.

What you're saying about your beliefs doesn't sound like anything contradicting either Plato or Tegmark.

Sorry I don't have a reference like that handy, but searching for Hyperuranion might be a good place to start.

Edit: that Wikipedia link actually gives a handy reference to Phaedrus 247b-c:

But of the heaven which is above the heavens, what earthly poet ever did or ever will sing worthily? It is such as I will describe; for I must dare to speak the truth, when truth is my theme. There abides the very being with which true knowledge is concerned; the colourless, formless, intangible essence, visible only to mind, the pilot of the soul. — Phaedrus

As I said, most philosophers would share your reservations about MUH, but not necessarily for that reason (the more common criticisms would be the same ones that are leveled against structural realism). — SophistiCat

I'm not sure that I understand structural realism, but wouldn't most philosophers be realists about numbers? And subsequently realists about mathematical entities in general?

Unfortunately, my background in general philosophy is not so strong. I have an S.B. in Philosophy, but it's in "Language and Mind", so other than Philosophy 101, I skipped over most of Philosophy that wasn't directly relevant to Philosophy of Mind. (Strangely, whether the term "water" means the same thing on Earth and Earth 2 was deemed a hugely important part of the debate on phenomenal consciousness back in the day. I wonder if it still is.)

Some, like Dennett, just don't accord "phenomenal consciousness" the kind of autonomous metaphysical status that philosophers like Searle, Nagel and Chalmers think it ought to have. — SophistiCat

Yes, that's for sure! But I still find it amazing when people seem to believe that phenomenal states could be purely mathematical. I'm no fan of physical identity theory for phenomenal states, for instance, but that makes more sense to me than phenomenal states being purely mathematical. I find that idea completely incredulous.

|>ouglas

"Mathematicism" seems to be the usual term used in philosophy circles, so maybe that would get more people's comprehension. — Pfhorrest

Perhaps so. At the time I was trying to have these discussions, Tegmark only had a single published paper on the topic. Maybe it hadn't been even been published at the time. I'd never heard anyone talk about it back then. I think I just stumbled upon it on Tegmark's web page.

And IMO it's more Pythagorean than Platonic, though I've heard it described as "radical Platonism" too. — Pfhorrest

Tegmark referred to his position as "radical Platonism" in the paper I read.

But I don't like that: I'm strongly anti-Platonist, as he separates the ideal from the physical, and debases the physical as not living up to the ideal, while I don't see mathematicism (whether ancient Pythagorean or modern Tegmarkian) as doing that. — Pfhorrest

Well, I guess that's where the "radical" comes in. Tegmark reduces everything that exists to only the ideal. What can be more ideal than pure math?

It's much like how I'm strongly anti-dualist but partial to something like (a more Berkeleyan, not Platonic) idealism, because it doesn't say that the mental is something apart from the physical, but that the physical is subsumed within the mental; — Pfhorrest

Okay, well I can certainly see phenomenal consciousness existing in a world where idealism is true, but I personally can't reconcile idealism and mathematicalism. To me, math is real and it is not ideas. All of math would exist even if there were never any intelligent beings to discover it.

To be honest, idealism doesn't really make any sense to me. Not unless we were to stipulate a form where the fundamental building blocks of physical existence are phenomenal or proto-phenomenal, and everything that's "physical" arises directly from that.

But I just can't buy mathematics alone, all by itself, doing that. Math is formal, eternal, discovered, unchanging, beautiful, and even more dead than a rock.

|>ouglas

Tegmark reduces everything that exists to only the ideal. What can be more ideal than pure math? — Douglas Alan

To me, math is real and it is not ideas. — Douglas Alan

These two statements seem to be in contradiction.

To me, math is real, and all ideas are reducible to math upon sufficient analysis.

All of math would exist even if there were never any intelligent beings to discover it. — Douglas Alan

I agree completely.

To be honest, idealism doesn't really make any sense to me. Not unless we were to stipulate a form where the fundamental building blocks of physical existence are phenomenal or proto-phenomenal, and everything that's "physical" arises directly from that. — Douglas Alan

That's exactly what I think. Everything is informational, formal, of a kind amenable to being described and worked with mathematically. All physical processes are interactions, signals being passed, between informational objects, which are defined entirely in terms of their function, which is to say how they map inputs to outputs (which become the inputs of other things). Being the recipient of such a signal, having informational input, is proto-phenomenal experience, so all physical things have such proto-phenomenal experience, and those experiences are ontologically the same events as the empirical properties they are experiences of, just seen from a different perspective, first person instead of third person. Proper consciousness like humans have, access consciousness, and intelligence, etc, are just particular kinds of complex, reflexive functions, physical functions like everything else, but like all physical things, made up of these informational functions, with their proto-phenomenal experiences, at the bottom. The phenomenal, the physical, the mathematical, is all the same stuff on my view.

All of math would exist even if there were never any intelligent beings to discover it. — Douglas Alan

This statement might be true if known mathematics were entirely discovered. But mathematicians have long pondered the question of mathematics being discovered or created. All the years I've studied and researched the subject have left me without a strong opinion in this regard. I would speculate that mathematics is both discovered and created, and if the latter, then non-existent prior to its creation.

It might be that one has to actually do research in the subject to understand the issue. Plato or no Plato. Maybe not.

There are a few other math guys on this forum, and they might provide their opinions. :chin:

This distinction between discovery and creation is actually very relevant to mathematicism. I hold that there isn't really a strong distinction between discovery and creation in the first place, when it comes to purely ideal things at least, discovering or creating mathematical or fictional or otherwise purely abstract things. Both creation and discovery of such things are the product of exploring an abstract space of possibilities. And if mathematicism like Tegmark's is correct, than that abstract space is actually a real space in a sense -- all those possible abstract constructs that could be invented already existed waiting to be discovered. Every story or song or image that is possible already "exists" in abstract sense, waiting for someone to find it worth writing down or recording or whatever; in much the same way that every number already "exists" in an abstract sense even if nobody's ever need to count exactly that many things or whatever so no human has ever used that number.

These two statements seem to be in contradiction. — Pfhorrest

The world "idealism" may have the word "ideal" in it, and I'm sure there's philosophical history as to why that's the case, but my statements do not contradict each other.

When I see the term "idealism" in the context of a discussion of consciousness, I infer that a Berkeleyesque subjective idealism is being referred to. This is the thesis that the fundamental building blocks of reality are minds. I.e., minds form reality, rather than reality forming minds. Or something along those lines. (I'm certainly no expert in this area of Philsophy.)

Platonic idealism, on the other hand, is the thesis that the world we live in is composed of imperfect instantiations of entities from another world where everything there is ideal (i.e., perfect).

I'm also no expert on ancient Philosophy, and it may be true that Plato believed that these perfect entities existed as ideas. But I'm pretty sure one could be a Platonist of a sort who believes that the world of perfect forms is not made up of ideas. And that reality is not formed by minds.

To me, ideas are things that exist in minds. Without minds there are no ideas. But the domain of perfect forms would exist, even if there were no minds to ponder on them.

Or at least that's how it seems to me.

|>ouglas

I doubt Tegmark's claim that "everything is mathematics" since, first of all, how could abstract mathematics per se generate any sort of physical reality? Seems preposterous to me.

And secondly, it seems even more preposterous that mathematics alone could give rise to consciousness, which we know is real because we experience it.