Physicalism can't be grounded in observation whether BIV or not. It's a matter of personal preference. Perhaps the BIV was very impressed by a physicalist professor. He feels dedicated to somehow uphold that view which seems conservative and somehow virtuous to him. The notion that the professor was just part of a program will be rejected due to this emotional bias.So epistemologically, the BIV has no grounds for their position. — Marchesk
However, it's also true that the vat and the brain are made up of physical stuff. — Marchesk
What could you observe that would confirm or disconfirm either direct realism or physicalism? — frank
We all make our philosophical arguments from some starting point, which will have some metaphysical basis. If one begins with there being a physical world that's directly perceived, then that rules out other problems that crop up with a different metaphysical starting point. — Marchesk
Funny enough that brain would not be him. — Heiko
You're saying that we observe the avoidance of problems associated with other viewpoints, and this is observational support for direct realism. — frank
They do have grounds. They have their empirical evidence. Problem is, you not given any clue as to the nature of the false reality being fed to this actual brain in a physical vat. If it is a story about a physical world, then the brain has grounds for their position. If on the other hand it is fed experience of a non-physical world, then it would have no empirical grounds.The problem for the BIV is that their perceptions are not of a physical world, but a mental one constructed by the false sensory and bodily impressions the vat is feeding the brain. So epistemologically, the BIV has no grounds for their position. — Marchesk
Assuming you are a BIV is not a physicalist position. You seem to say this yourself:However, it's also true that the vat and the brain are made up of physical stuff. So our BIV physicalist, while admitting they could be envatted, could argue that mental states are still physical.
OK, you call it a direct realist here, but that is more or less the physicalist position: that what one perceives is the stuff that we're made of. The physics of the empirical reality being fed to the BIV would need to be capable of producing a conscious observer for physicalism to be a defensible position.It can if one is a direct realist, because then you're perceiving the actual physical objects, instead of being aware of some mental intermediary. — Marchesk
Let's say a person is actually a brain in a vat. They are convinced that physicalism is the case, which is to say that all of reality is made up of the stuff of physics without exception
How did this brain come to believe there is actually a physical world (a sine qua non for physicalism)? That is an essential question, because it has bearing on the rationality of its belief. — Relativist
OK, you call it a direct realist here, but that is more or less the physicalist position: that what one perceives is the stuff that we're made of. — noAxioms
The physics of the empirical reality being fed to the BIV would need to be capable of producing a conscious observer for physicalism to be a defensible position. — noAxioms
Physicalism can't be grounded in observation whether BIV or not
One can't empirically verify a negative (physicalism is the doctrine that no non-physical things exist). However, it may be reasonable to infer that only physical things exist because there's no evidence of anything else existing - that is still "grounded" in observation.What is the difference between "grounded in observation" and "empirically verified"?
It is pretty easy to disprove a literal brain (a pink biological thing like in the pictures) in a vat scenario. Everybody would have two brains, one in the vat (in charge) and one in the body (epiphenomenal). Somebody would notice the difference that signals from the body one are severed abruptly at some point in the brain stem to be replaced with uncaused signals controlling the motor functions.On a Denettian position, it's difficult to see how being envatted and experiencing a fake physical world is possible. And in fact, Dennett has denied this is actually possible, because he doesn't think a computer program can handle the combinatorial explosion of interacting with a fake physical world. — Marchesk
It is pretty easy to disprove a literal brain (a pink biological thing like in the pictures) in a vat scenario. Everybody would have two brains, one in the vat (in charge) and one in the body (epiphenomenal). Somebody would notice the difference that signals from the body one are severed abruptly at some point in the brain stem to be replaced with uncaused signals controlling the motor functions.
Defects would be a distinguishing point. Bob has an aneurysm in the vat and displays the physical symptoms of that, but doctors find a brain with nothing wrong with it. Sue on the other hand has an aneurysm in the body brain, and yet continues to function normally, even after doctors notice the event (for whatever reason). — noAxioms
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