Mathematical platonism is ridiculous quasi-religious mumbo-jumbo that keeps philosophers employed.
You've only ever explained a circle to other humans. You've only ever learned about circles from other humans, or artifacts (not circles!) authored by humans.
No human has seen a perfect mathematical circle with their senses, because they don't exist as physical objects outside of our skulls. They exist as physical objects inside our skulls in the form of neural correlates and latent representations.
A circle is like a meme. It's compelling because it's so simple (to us anyway). But, try to really explain a mathematical circle to a six year old and especially how it is different from the representation of a circle that you've just drawn. Watch even a smart kid struggle a bit with this, before getting it. It's not as simple as we might think, having mastered the concept. That doesn't mean it has an independent existence in some realm that is not embodied. It just means the concept is hard, then simple due to its abstractness and otherworldly simplicity / power balance.
Sure but your argument is so broad that it applies to everything then. Apples don't exist, cars don't exist, the color blue doesn't exist. By the same standard that you hold circle to, you have never actually seen an actual apple, or blue, or a car.
If you hold any of these extreme views you end up with quasi-religious mumbo-jumbo. The challenge is at what point do you draw the line so that one can say that an apple really does actually exist, but the square root of -1 does not exist? What about an electron or a gluon, do those actually exist in the same way an apple possibly exists? What about a virtual particle? Do those actually exist or are they also memes whose only existence is as neural correlates? If their only existence is as neural correlates, does that mean that they can't exist as "transistor" correlates? What about other forms of matter, can they also correlate so as to give an existence to an apple or is there something special and unique about neurons?
It's the investigation of that question itself that is of interest, and I think quite valuable, both in principle as well as useful from a programming point of view.
> It's the investigation of that question itself that is of interest, and I think quite valuable, both in principle as well as useful from a programming point of view.
I agree, but I believe our progress in this area is hindered by unjustified ideas like platonism inherited from our history of religion and spiritual belief. They bias us towards unnecessary non-materialism.
> Sure but your argument is so broad that it applies to everything then.
No. When I said no one has really seen a circle, I wasn't distinguishing between sense impressions / predictions and some external reality. As you point out, that would be problematic. But there is no true apple form. Granted, there may be stereotypical apples.
A mathematical circle is different. It has equal radius everywhere in a continuum (real numbers). It has no thickness. These are essential features of a mathematical circle. I have never seen such an object. Neither has anyone else. It can't be built out of matter, which is probably the appeal of platonism. It does exist in material form in our heads, not outside. It can be reasoned about. We can draw approximations to it. This changes nothing for working with math, as others have pointed out. We should obviously choose to speak in terms of circles when doing math, instead of specifying the exact neural correlates of circle, but it's a matter of abstraction and utility.
Regarding fundamental? particles, we recognize that these are features of our current model of reality.
We can certainly talk about abstract concepts, but there is no reason to think that they exist without physical correlates. That doesn't lessen the usefulness of the (possibly leaky) abstractions.
Regarding other substrates. Yes, figuring out what other substrates could possibly support what I experience as consciousness, and what others report as consciousness is very interesting/useful. I'm working on this now.
I think we get in trouble though when we define consciousness too broadly.
I think that your insistence that your own existence is substantially different than that of an ideal circle is the real "quasi-religious mumbo-jumbo".
"Physical reality" is just your way brain's way of interpreting the mathematical rules that constitute our existence. Yes, there is an external reality that can bite, because it is composed of rules that apply equally to all the minds within it, but it is the minds that make a "reality" rather than simply existence. A circle has no mind, no viewpoint to make its existence feel real, but it exists no less.
Heh... and neither can you take it as a given that physical objects outside of your skull have a more substantial existence than mathematical ones.
Let's do a simple thought experiment... Do you believe that GAI is possible on conventional computers? If you do, then you must believe that a mind not significantly different from yours can exist inside a particular configuration of Conway's Game of Life (since Turing machines exist in GoL). But GoL is purely mathematical, so the mind-in-GoL is composed of, and senses and interacts with, objects "external" to it which are purely mathematical.
But... 1) such objects would seem "physical" to the mind-in-GoL, and 2) both mind-in-GoL and its entire reality are fully deterministic and their existence is thus entirely independent of them ever being "simulated" (or instantiated) on an "actual" computing device. If they can exist, they can be said to actually exist, regardless of any external (to them) observer observing them. One of us running such a GoL configuration on one of our computers is just a way for us to create a window into that existence, not to "bring it into being".
In short, if you believe that GAI is possible and that your physical reality is posited within an essentially deterministic Universe (and here it does not matter much how you resolve the quantum dilemma), then there is no reason to give physical objects a privileged position over mathematical ones. In other words, your position is based on nothing but "quasi-religious mumbo-jumbo", an unjustifiable faith that your existence is special.
Is it though? Humans play GoL on computers made out of matter, think about GoL using brains made out of matter, and learn or communicate about GoL using artifacts made of matter. We can port GoL to various devices, so it seems that the essentials of GoL are not tied to a particular physical substrate. But then again, these are only approximations to GoL in that storage, etc. is limited. Anytime we actually run GoL, we're doing it in some embodied form. GoL doesn't play itself in some non-material plane.
I think we get in trouble with these sweeping thought experiments and extrapolations. I might agree in principle that a mind like mine could exist in GoL, but it could turn out that to implement it would take some enormous combinatorial number multiple of universes. Then does it exist in a form that could operate, or only in a form that I can sketch out to others without understanding or giving any details?
We really need to be careful about 1, 2, ..., infinity style arguments. They're second-nature to mathematicians, but the history of mathematics is full of cases where we had to clean up the mess left over after inviting infinity to the party.
EDIT> "2) both mind-in-GoL and its entire reality are fully deterministic and their existence is thus entirely independent of them ever being "simulated" (or instantiated) on an "actual" computing device. If they can exist, they can be said to actually exist"
How is this not just restating the same unsupported argument? Now we'll just have to debate what "exist" means, which is more or less where we started.
EDIT 2> This is what I mean by keeping philosophers employed. Instead of making progress and deepening our understanding, we just end up debating and then agreeing-to-disagree on what word X means, and what it means to mean, and whether meaning can be said to exist, and ..., and ..., recursion
But isn't philosophy (and religion) nothing but disagreement? (If philosophers agreed with each other, we'd very few philosophy books; in contrast, despite the fact that there are many, many mathematics books, those are pretty much all saying the same things.)
One could say that mathematics does not study (abstract) objects; rather, it studies relations that do, in fact, exist between (real) objects. Even a circle is merely a relation - that between what lies on the circumference and, for example, what's at the center (or the axis, if we speak about a cylinder); this also manifests itself in the form of rotation, ostensibly a physical phenomenon.
But relations are physical; the fact that they are the sole focus of mathematics (unlike physics where focus is also on objects and processes) does not change that.
In the sense that they exist in nature. Natural numbers (correctly understood as relations) exist, for example, as atomic valences which permit certain interactions between atoms while preventing others. (This has nothing to do with the Platonism BTW.)
If to you relations exist in nature therefore they are physical, there is a physicalist assumption in there which doesn't go without saying.
Now, I happen to have sympathy for that position, but it's hardly as straightforward as you seem to imply.
Where it does have a lot to do with Platonism is that positing that relations are not abstract things but physical entities presumably entails that you can show what a relation physically is. And an instance of a relation isn't the relation. As soon as you go into "for example", you're not talking about the object itself anymore.
It pays to draw a distinction between objects and relations. Relations manifest themselves when more than one object is involved. A pair of objects is an object; it is a physical relation between pairs, the isomorphism if you will, that we call "number 2"; it manifests itself in cases when pairs can physically "snap" together solely due to the fact that their cardinalities match. I think it is the fact that a number (a count, in this case) is not tied to a single object (e.g. a pair) but rather expresses the potential of a certain physical interaction between several objects that makes understanding this difficult.
You've only ever explained a circle to other humans. You've only ever learned about circles from other humans, or artifacts (not circles!) authored by humans.
No human has seen a perfect mathematical circle with their senses, because they don't exist as physical objects outside of our skulls. They exist as physical objects inside our skulls in the form of neural correlates and latent representations.
A circle is like a meme. It's compelling because it's so simple (to us anyway). But, try to really explain a mathematical circle to a six year old and especially how it is different from the representation of a circle that you've just drawn. Watch even a smart kid struggle a bit with this, before getting it. It's not as simple as we might think, having mastered the concept. That doesn't mean it has an independent existence in some realm that is not embodied. It just means the concept is hard, then simple due to its abstractness and otherworldly simplicity / power balance.
EDIT> apostrophe