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That other "universe" is just patterns embedded in our brains. That's all you need. You could likewise argue that sounds exist in a different universe, but are

by Retra 8y ago

That other "universe" is just patterns embedded in our brains. That's all you need. You could likewise argue that sounds exist in a different universe, but are only "embedded" into the air using pressure waves, but why would you ever think you needed a different universe of sounds when you've already got pressure waves in air? I mean... what's "not enough" about that for you? >What we call "physical existence" could is also probably just be "math all the way down". This is a needless diversion. Mathematics is the study of structure. Physical reality has structure, and very well could "be structure" in some equivalent sense, but to say it is math is just abject poetic nonsense. This change of language would literally make no significant difference to anybody about anything. You may as well be declaring the world to be flat and asking everybody else to go and change all our language to make it true.

incompatible 8y ago
Yeah, mathematical objects like numbers are concepts in our brains, or imaginary objects. Numbers in particular are imaginary objects used for counting. You can set up an isomorphism between these numbers and real-world objects, e.g., to count them.
roywiggins 8y ago
The strange thing about mathematics, as opposed to other noncorporeal ideas, is that it is nearly uniquely suited to being transmitted between brains. My idea of the number "three" and your idea the number "three" are probably very similar. This sort sensation that they have an independent existence leads people to the Platonic notion of a mathematical "realm" or "universe". (personally I think mathematics exists in our brains, but also and crucially in the interactions between our brains, since a proof is never accepted until it is reviewed and so on. A proof that's just in my brain is no proof at all, even if it happens to be correct)
- Retra 8y ago
  You could say that about most language we use: it's meant for transmitting thoughts between human brains. Why would it be bad at it? Besides, there are plenty of mathematical concepts which are hard to understand. I don't see any uniqueness to math here.
kazinator 8y ago
> abject poetic nonsense. No it isn't! Either it is math all the way down, or else it isn't. If it isn't, then what is at the bottom? So this is actually an existential question. Suppose we reach a final description of reality that is entirely accurate (no longer an approximation that fails to account for some structures and processes). Won't that description consist of nothing but math? Then, if it is complete, how does that description account for the fact that reality isn't math? If there is a difference between reality and math, can't that be described with math, so then it goes away? If you want math to just be a description of a structure that itself isn't math, then the structure has to have attributes that are not covered by the math. The math is then using a substitute structure with fewer properties as a proxy for that structure. Once all the attributes are rolled into the math, there ceases to be a difference between that target structure and the math; it is that mathematical object. To prove otherwise requires one to name the difference. If two entities are completely described and found to be the same, they are just one entity. > You may as well be declaring the world to be flat. It is testable that the world isn't flat.
- jakeinspace 8y ago
  My guess is that eventually, if we manage to ever reach that point of total knowledge, there are certain properties of the universe that exist for no reason; they just are. Whether that's at the level of today's fundamental particles/qft or much deeper is anyone's guess. Example: space-time exists in n(>=4) dimensions, there are several quantum fields that exist in that space-time and evolve/interact according to the equations of qft, gravity has some mathematical description (better than the ones we have now). And that's it, there's nothing else for us to know. Of course, we can never know for certain whether we've bottomed-out our description of reality, so physicists will always have some hope. Now, if the universe is described entirely by mathematics, bootstrapped by a few base cases (the existence of fields/particles/space-time/strings/etc), I'd be comfortable with that. I'm not sure what a truly satisfying understanding of reality would look like beyond that.
  - kazinator 8y ago
    > there are certain properties of the universe that exist for no reason; they just are. But we have that in math and logic: axioms! > Of course, we can never know for certain whether we've bottomed-out our description of reality That we do not know is a fact; but is it a fact that we can never know? What if one fine day we do know?

by Retra 8y ago

incompatible 8y ago

Yeah, mathematical objects like numbers are concepts in our brains, or imaginary objects. Numbers in particular are imaginary objects used for counting. You can set up an isomorphism between these numbers and real-world objects, e.g., to count them.

roywiggins 8y ago

The strange thing about mathematics, as opposed to other noncorporeal ideas, is that it is nearly uniquely suited to being transmitted between brains. My idea of the number "three" and your idea the number "three" are probably very similar. This sort sensation that they have an independent existence leads people to the Platonic notion of a mathematical "realm" or "universe". (personally I think mathematics exists in our brains, but also and crucially in the interactions between our brains, since a proof is never accepted until it is reviewed and so on. A proof that's just in my brain is no proof at all, even if it happens to be correct)

Retra 8y ago
You could say that about most language we use: it's meant for transmitting thoughts between human brains. Why would it be bad at it? Besides, there are plenty of mathematical concepts which are hard to understand. I don't see any uniqueness to math here.

kazinator 8y ago

> abject poetic nonsense. No it isn't! Either it is math all the way down, or else it isn't. If it isn't, then what is at the bottom? So this is actually an existential question. Suppose we reach a final description of reality that is entirely accurate (no longer an approximation that fails to account for some structures and processes). Won't that description consist of nothing but math? Then, if it is complete, how does that description account for the fact that reality isn't math? If there is a difference between reality and math, can't that be described with math, so then it goes away? If you want math to just be a description of a structure that itself isn't math, then the structure has to have attributes that are not covered by the math. The math is then using a substitute structure with fewer properties as a proxy for that structure. Once all the attributes are rolled into the math, there ceases to be a difference between that target structure and the math; it is that mathematical object. To prove otherwise requires one to name the difference. If two entities are completely described and found to be the same, they are just one entity. > You may as well be declaring the world to be flat. It is testable that the world isn't flat.

jakeinspace 8y ago
My guess is that eventually, if we manage to ever reach that point of total knowledge, there are certain properties of the universe that exist for no reason; they just are. Whether that's at the level of today's fundamental particles/qft or much deeper is anyone's guess. Example: space-time exists in n(>=4) dimensions, there are several quantum fields that exist in that space-time and evolve/interact according to the equations of qft, gravity has some mathematical description (better than the ones we have now). And that's it, there's nothing else for us to know. Of course, we can never know for certain whether we've bottomed-out our description of reality, so physicists will always have some hope. Now, if the universe is described entirely by mathematics, bootstrapped by a few base cases (the existence of fields/particles/space-time/strings/etc), I'd be comfortable with that. I'm not sure what a truly satisfying understanding of reality would look like beyond that.
- kazinator 8y ago
  > there are certain properties of the universe that exist for no reason; they just are. But we have that in math and logic: axioms! > Of course, we can never know for certain whether we've bottomed-out our description of reality That we do not know is a fact; but is it a fact that we can never know? What if one fine day we do know?