Of course, the physical world is very special, it is this particular thing with these particular properties, and we happen to have evolved and live in it, but that doesn’t seem fundamentally different from how the complex plane is another particular thing with its own properties. Also, like “physical” is not a meaningful distinction in the sense that it doesn’t say anything specific about properties of the world, also “mathematical structure” is not a meaningful distinction in the same sense, and so insisting that the physical world “is a mathematical structure” doesn’t seem meaningful.
Every existing thing has a structure, but it is not clear that every logically consistent structure is the structure of an existing thing. The distinction between instantiated and uninstantiated mathematical structures is not obviously meaningless. The Tegmark hypothesis is that this distinction is meaningless. Since this meaninglessness is not obvious, the Tegmark hypothesis is nontrivial.
A way to tell an instantiated mathematical-structure-containing-sentient-beings from an uninstantiated one. (That doesn’t sound very different from telling conscious beings from philosophical zombies to me.)
I don’t know whether the concept of existence is meaningful. If it is, then something like the following should work:
To determine whether a mathematical structure M is instantiated, examine every thing that exists. If M is the structure of something that you examine, then M is instantiated. Otherwise, M is not instantiated.
Thus, whether the concept of existence is meaningful is the heart of the problem. I don’t claim to know that this concept is meaningful. I claim only not to know that it is meaningless.
I think it’s more like there are several concepts which share the same label. If a tree falls in the forest, and no one hears it, does it make a sound?
The tree in the forest is a case of various clear concepts (of sound) clearly implying different true answers.
The problem of Being is a problem of finding a clear concept that implies answers that many people find intuitively plausible.
It is more like the problem of being perfectly confident that various mathematical statements are true, while finding it very difficult to say just what it is that those statements are true about.
*points at objects which are instances of a class*
Those are instantiated (classes).
*points at classes that are unused at runtime, do not have any real object instances, perhaps were never even coded, but are simply logically consistent*
The distinction between instantiated and uninstantiated mathematical structures is not obviously meaningless.
The Tegmark hypothesis is that this distinction is meaningless. Since this meaninglessness is not obvious, the Tegmark hypothesis is nontrivial.
I’m making a distinction between saying “physical world is a structure” and “physical world has structure”: the first form seems to demand something unclear, and the latter seems to suffice for all purposes. Suppose things may either exist or not; but structure of things is abstract math, so it does seem clear that the properties of a structure don’t care whether it’s “instantiated” or not: the math works out according to what the structure is, regardless of which things have it. And since we only reason about things in terms of their structure, a distinction that isn’t reflected in that structure can’t enter into our reasoning about them.
(It might be possible to cash out “existence” of the kind physical world has as a certain property of structures, probably something very non-fundamental, like human morality, but this interpretation seems unlike the kind of confusion the argument is meant to counter.)
Every existing thing has a structure, but it is not clear that every logically consistent structure is the structure of an existing thing. The distinction between instantiated and uninstantiated mathematical structures is not obviously meaningless. The Tegmark hypothesis is that this distinction is meaningless. Since this meaninglessness is not obvious, the Tegmark hypothesis is nontrivial.
Define instantiated.
What would constitute a definition for your purposes?
A way to tell an instantiated mathematical-structure-containing-sentient-beings from an uninstantiated one. (That doesn’t sound very different from telling conscious beings from philosophical zombies to me.)
I don’t know whether the concept of existence is meaningful. If it is, then something like the following should work:
To determine whether a mathematical structure M is instantiated, examine every thing that exists. If M is the structure of something that you examine, then M is instantiated. Otherwise, M is not instantiated.
Thus, whether the concept of existence is meaningful is the heart of the problem. I don’t claim to know that this concept is meaningful. I claim only not to know that it is meaningless.
I think it’s more like there are several concepts which share the same label. If a tree falls in the forest, and no one hears it, does it make a sound?
The tree in the forest is a case of various clear concepts (of sound) clearly implying different true answers.
The problem of Being is a problem of finding a clear concept that implies answers that many people find intuitively plausible.
It is more like the problem of being perfectly confident that various mathematical statements are true, while finding it very difficult to say just what it is that those statements are true about.
*points at objects which are instances of a class*
Those are instantiated (classes).
*points at classes that are unused at runtime, do not have any real object instances, perhaps were never even coded, but are simply logically consistent*
Those are uninstantiated (classes).
Perhaps that’ll help seeing it.
I’m making a distinction between saying “physical world is a structure” and “physical world has structure”: the first form seems to demand something unclear, and the latter seems to suffice for all purposes. Suppose things may either exist or not; but structure of things is abstract math, so it does seem clear that the properties of a structure don’t care whether it’s “instantiated” or not: the math works out according to what the structure is, regardless of which things have it. And since we only reason about things in terms of their structure, a distinction that isn’t reflected in that structure can’t enter into our reasoning about them.
(It might be possible to cash out “existence” of the kind physical world has as a certain property of structures, probably something very non-fundamental, like human morality, but this interpretation seems unlike the kind of confusion the argument is meant to counter.)