An Interesting Challenge to Physicalism, 2022

Standard disclaimer, I'm not an expert, just an amateur who enjoys learning about and sharing this stuff.

Arguing metaphysics with Mark P Xu Neyer. [link]. His most recent response to me looks like it would require me to write about three different essays! I'll sort of summarize and link to further reading for now. Especially since further conversation might reveal things that I can't anticipate, so I can't answer it all right now, even if I had the time and motivation.

Might be best to go in this order:


 * 1) Objective beliefs, and objective values
 * 2) Ontology of numbers on physicalism
 * 3) What about Max Tegmark, etc.?

Beliefs and Values
(a lot of the following discussion of beliefs and values can be accepted whether or not someone accepts physicalism)(after all, this is the place I'm starting, it makes sense that it should potentially be a kind of common ground we can share)

Of course to choose some belief as “better” requires some evaluation. That means some values, or desires. Normally people assume that truth is valuable, but you might ask: "is it really?" But notice what this is really asking: "is it true that truth is valuable?". So you can't really escape it, even by questioning it. See my musings on what is most important (figuring out "what to value" is itself kind of the most valuable thing), as well as the equivalence of figuring out what is true and figuring out what to do. As well, my notes on truth, and whether we can use something other than truth (like, in Mark's comment, entrails or whatever). Putting this together, I think we have at least a bit of a foundation for evaluating differetn beliefs to see which is a "better choice": based on truth.

Questioning our values is one way to avoid "smuggling" them in. But I also think that, to an extent, what we like is an immediately observable fact. Like seeing what color something is with our own eyes. So questioning is only necessary to be sure our "eyes" are not deceiving us (which they sometimes do). We don't have to start from nothing.

There's also plenty of writing by people other than me that is relevant to this subject:


 * Richard Carrier's writings:
 * Epistemological Endgame digs down to the root of this:
 * "We are thus faced with an ultimate choice: K or ~K? Which principle do I follow? I can try them both out right now, and immediately see that following K leads to correct predictions and the satisfaction of my desires and the fulfillment of my plans, while following ~K does much poorly in all three respects."
 * his more recent "The Objective Value Cascade" also seems quite relevant. This time going down to a kind of root of "should we value anything at all?"
 * his "Epilogue to the Sam Harris Moral Facts Contest":
 * "Even at the level of choosing not just actions, but values. An “ideal you” would choose a set of values that might differ from the values you have now, and that is a statement of fact about how a machine (your brain) will operate in a given factual condition (being rational and possessed of true beliefs)."
 * "In the most reductive sense, all moral propositions, of the form “you ought to do A,” are predictive hypotheses about how your brain would function in an ideal condition. If your brain was put in a state wherein it made no logical error (no step of reasoning in its computing of what to believe, value, or do was fallacious) and had all requisite information (no relevantly false beliefs, and all relevant true beliefs), then it would in fact do A. And in telling someone they ought to do A, we are really saying they are acting illogically or ignorantly if they don’t; that even they themselves would recommend they do A, if they were more informed and logical."
 * his deep dive into the "Argument from Reason" discusses how all of this reasoning stuff can be physical, rather than supernatural. (this might be more relevant later, when discussing "how numbers can be physical").

Just in case there is a question about how values are physical: it's easy enough to think of physical cause and effect. Having a particular value can cause you to do something different than if you didn't have that particular value. I don't know if these come down to individual neurons, or structures of them, or what, but some physical explanation seems possible, and quite likely to be found. (beliefs can also be described and explained in a similar way)
 * Eliezer Yudkowsky's “The simple truth" is one I come back to a lot. It's an allegory for the technology of truth/belief.  And it even outlines how it can work as a physical system.  It's very enjoyable to read, but the ending of the story always feels a bit mean to me.  [oh dear, the character's name is Mark!  So in this case it's especially awkward]
 * it is very much talking about stuff like Mark's "entrails" comment: "I try several methods: I toss the divination sticks of my tribe; I train my psychic powers to locate sheep through clairvoyance; [...]"

Ontology of numbers on physicalism
Personally I find it a bit difficult to see the difficulty of explaining numbers on physicalism. Some of our most well-known physical technologies, such as computers and calculators, seem to handle numbers even better than they handle other things. It's within reach for me or you to learn how these objects physically do what they do. Even at the stage of counting things, we have computers capable of pattern recognition, identifying objects, and counting how many of them there are (see Object Counting in computer vision, for example at this link). It's not always as easy to see what the human brain is up to, but we can both imagine how it might work, and see some neuroscience that looks a lot like what I would have expected. While writing this I use a hand-held measuring tool, like a physical ruler, as an analogy. Then I was going to say we would expect to have something similar in our heads. Then I searched on google for neuroscience of counting, and my idea looks a lot like what this link claims. Here's another link on some neuroscience of counting.

Googling Richard Carrier and the Ontology of numbers will also bring up numerous results:


 * How My Philosophy Would Solve the Unsolved Problems
 * Plantinga’s ‘Two Dozen or So’ Arguments for God: The Onto-Metaphysical Arguments
 * How Can Morals Be Both Invented and True?, also referenced in Eight Philosophical Questions We’ll Never Solve?
 * Defining Naturalism

My attempt to define numbers years ago:


 * A label selected from a series of unique labels that are in a fixed order, with a beginning.  For a given set of items, each item receives a unique label given out in the same order as the list of labels is defined, beginning with the beginning label.  A set itself can receive a label that is the same as the final label applied to the items in the set. Then you just have to invent names for those labels.  The beginning we call "one", and so on.

What about Max Tegmark, etc.?
I’m not very familiar with Tegmark’s views. It appears that most of it will work a lot like physicalism. I’ll trust your perspective to find any unanswered questions.

While Tegmark's views appear very similar to physicalism, the emphasis is on "reality is mathematical" or "reality is a mathematical structure", and I confess I don't know what that means. First step would be to find out what a mathematical structure is. But I confess the statements seem wrong on an entirely different level. They almost appear grammatically incorrect to me. Another thought that comes to mind is that it seems a bit like saying that "reality is scientific", or that "the nature of the universe is that it is a scientific theory". It just doesn't sound right at all. Sounds mixed up like that to me.

From my discussion of numbers, it should t least be clear that all of reality is not the same as this part of our brains that measures quantities and keeps track of them and stuff. No more than all of reality is a ruler in your hand. We do our best to create a "map" in our heads that matches reality [that map is our beliefs, theories, etc.]. And it seems to me that the word "mathematics" really refers to this tool kind of thing.

On his website, he replies to stuff like this:


 * Q: Aren't you conflating the description with the described when saying that our physical reality *is* mathematical rather than just being *described* by math?
 * A: [...] Our language for describing the planet Neptune (which we obviously invent - we invented a different word for it in Swedish) is of course distinct from the planet itself. Similarly, we humans invent the language of mathematics (the symbols, our human names for the symbols, etc), but it's important not to confuse this language with the structure of mathematics. For example, as mentioned above, any civilization interested in Platonic solids would discover that there are precisely 5 of them (the tetrahedron, cube, octahedron, dodecahedron and icosahedron). Whereas they're free to invent whatever names they want for them, they're *not* free to invent a 6th one - it simply doesn't exist. [...] The possibility that I explore in the book is that one of the structures of mathematics (which we can discover but not invent) corresponds to the physical world (which we also discover rather than invent).

He's right that the language of math is different from the structure of it. Just like our name for a ruler" is different from a ruler in our hands. And even with numbers and math in our own heads:  the part of the brain actually doing the math stuff (like counting, subtracting, multiplying, etc.) is also not the same part that has names for all of those numbers and operations and so on.  But it's still a thing in there, and when we say "mathematics", we are talking about this kind of thing.  Just like with a ruler.  The ruler might not be the same as our language to describe the ruler, but the ruler is still not the same as the stuff we are measuring.  So there's three things.  The language, the measuring device, and the thing we are measuring.

At that last part, he says that "one of the structures of mathematics (which we can discover but not invent) corresponds to the physical world", and this sounds much more comprehensible. The measuring device (a mathematical structure) can be compared to the universe, and maybe we see that they match. That's what I'd say. But based on his other statements, maybe when he says "corresponds", he means something else, and is once again mixing things up.