This thought experiment always seemed silly to me. As if somehow the experience of the visual cortex reacting to “color” input was not a piece of knowledge.
If someone has a poor ability to mentally visualize 3-dimensional objects, and is shown a set of formula that will draw a specific and very odd object (learning everything but what the object actually looks like), and is only ever allowed to graph on paper, then of course when we finally hand them a physical model of the object we have given them new information.
I don’t see this as any different. We have imposed some limitation on a subject, given them every piece of knowledge that the limitation allows for, and then called this “all knowledge” (which it clearly is not). After you remove the limitation and the final pieces of knowledge are gained, you have not demonstrated that non-physical knowledge exists. The fallacy was calling the knowledge given to the restricted subject complete, when it was in fact not.
The knowledge is only new because of a PHYSICAL limitation that previously existed. Once the PHYSICAL limitation was removed, a PHYSICAL interaction resulted in new PHYSICAL knowledge.
All you have demonstrated is that it is possible restrict knowledge.
I think you’re mistaking the conclusion that the non-reductionist philosophers draw from the thought experiment. They’re not generally substance dualists like Descartes. Instead, they claim that reductionism is false because it is epistemically incomplete, even within a purely physical world: a human (or an AI, or anything other than a bat) cannot ever understand the experience of being a bat, and therefore not all knowledge reduces to mathematical patterns of physical objects.
The knowledge Mary has is all physical knowledge, where physical knowledge
means the kind of thing that can be found in books. You deam the further, experiential
knowledge she gains to be physical because sensory processing is physical, but that is a different sense of physical. If you think she learns something on exiting the room, and it seems you do, then you are conceding part of the claim, the part about the incompleteness of physical explanation, even if you insist that the epistemic
problem doesn’t lead to an dualistic metaphysics.
Only insofar as the definition of physical is limited to things you can find in books. I wholly reject such a definition.
@ Orthonormal. The conclusion seems to me to come very naturally from the thought experiment, if you allow for its assumptions. But that is what I think is silly, its assumptions. The thought experiment tries to define “all knowledge” in two different and contradictory ways.
If Mary has all knowledge, then there is nothing left for her to learn about red. If upon seeing red she learns something new, then she did not have all knowledge prior to seeing red.
It is their definition of knowledge, which is inconsistent, that leads to the entire thought experiment being silly.
The practical point is that, if not all knowledge reduces to mathematical patterns of physical objects (the sort of thing that we can organize and learn from textbooks), then the actual project of reductionists becomes futile at a really early stage- we’d have to give up on fully understanding even a worm brain, since we could never have the knowledge of its worm-qualia.
I want to respond to your claim more thoroughly, but my response essentially consists of the second and third posts here. If you want to pick up this conversation on those threads, I’m all for it.
This thought experiment always seemed silly to me. As if somehow the experience of the visual cortex reacting to “color” input was not a piece of knowledge.
If someone has a poor ability to mentally visualize 3-dimensional objects, and is shown a set of formula that will draw a specific and very odd object (learning everything but what the object actually looks like), and is only ever allowed to graph on paper, then of course when we finally hand them a physical model of the object we have given them new information.
I don’t see this as any different. We have imposed some limitation on a subject, given them every piece of knowledge that the limitation allows for, and then called this “all knowledge” (which it clearly is not). After you remove the limitation and the final pieces of knowledge are gained, you have not demonstrated that non-physical knowledge exists. The fallacy was calling the knowledge given to the restricted subject complete, when it was in fact not.
The knowledge is only new because of a PHYSICAL limitation that previously existed. Once the PHYSICAL limitation was removed, a PHYSICAL interaction resulted in new PHYSICAL knowledge.
All you have demonstrated is that it is possible restrict knowledge.
I think you’re mistaking the conclusion that the non-reductionist philosophers draw from the thought experiment. They’re not generally substance dualists like Descartes. Instead, they claim that reductionism is false because it is epistemically incomplete, even within a purely physical world: a human (or an AI, or anything other than a bat) cannot ever understand the experience of being a bat, and therefore not all knowledge reduces to mathematical patterns of physical objects.
The knowledge Mary has is all physical knowledge, where physical knowledge means the kind of thing that can be found in books. You deam the further, experiential knowledge she gains to be physical because sensory processing is physical, but that is a different sense of physical. If you think she learns something on exiting the room, and it seems you do, then you are conceding part of the claim, the part about the incompleteness of physical explanation, even if you insist that the epistemic problem doesn’t lead to an dualistic metaphysics.
Only insofar as the definition of physical is limited to things you can find in books. I wholly reject such a definition.
@ Orthonormal. The conclusion seems to me to come very naturally from the thought experiment, if you allow for its assumptions. But that is what I think is silly, its assumptions. The thought experiment tries to define “all knowledge” in two different and contradictory ways.
If Mary has all knowledge, then there is nothing left for her to learn about red. If upon seeing red she learns something new, then she did not have all knowledge prior to seeing red.
It is their definition of knowledge, which is inconsistent, that leads to the entire thought experiment being silly.
If you want to call someone’s attention, replying directly to their comment is a great way of doing that.
The practical point is that, if not all knowledge reduces to mathematical patterns of physical objects (the sort of thing that we can organize and learn from textbooks), then the actual project of reductionists becomes futile at a really early stage- we’d have to give up on fully understanding even a worm brain, since we could never have the knowledge of its worm-qualia.
I want to respond to your claim more thoroughly, but my response essentially consists of the second and third posts here. If you want to pick up this conversation on those threads, I’m all for it.
Also, welcome to Less Wrong!
Your later posts do a better job of describing your position here. I don’t think we disagree.