FWIW, my original comment talked about a realistic version of brain in a vat, not the philosophical idealized model. But now that I thought about it some more, the idealized model is seeming harder and harder to implement.
The robots who take care of my vat must possess lots of equipment besides electrodes! A hammer, boxing gloves, some cannabis extract, a faster-than-light transmitter so I can’t measure the round-trip signal delay… Think about this: what if I went to a doctor and asked them to do an MRI scan as I thought about stuff? Or hooked some electrodes to my head and asked a friend to stimulate my neurons, telling me which ones only afterward? Bottom line, I could be an actual human in an actual world, or a completely simulated human in a completely simulated world, but any in-between situations—like brains in vats—can be detected pretty easily.
Um, if you’re a brain in a vat, then any “brain” you perceive in the real world like on a “real world” MRI is nothing but a fictitious sensory perception that the vat is effectively tricking you into thinking is your brain. If you’re a brain in a vat, you have nothing to tell you that what you perceive as your brain is actually really your brain. It may be hard to implement the brain in the vat scenario, but when implemented, its absolutely undetectable.
FWIW, my original comment talked about a realistic version of brain in a vat, not the philosophical idealized model. But now that I thought about it some more, the idealized model is seeming harder and harder to implement.
The robots who take care of my vat must possess lots of equipment besides electrodes! A hammer, boxing gloves, some cannabis extract, a faster-than-light transmitter so I can’t measure the round-trip signal delay… Think about this: what if I went to a doctor and asked them to do an MRI scan as I thought about stuff? Or hooked some electrodes to my head and asked a friend to stimulate my neurons, telling me which ones only afterward? Bottom line, I could be an actual human in an actual world, or a completely simulated human in a completely simulated world, but any in-between situations—like brains in vats—can be detected pretty easily.
Um, if you’re a brain in a vat, then any “brain” you perceive in the real world like on a “real world” MRI is nothing but a fictitious sensory perception that the vat is effectively tricking you into thinking is your brain. If you’re a brain in a vat, you have nothing to tell you that what you perceive as your brain is actually really your brain. It may be hard to implement the brain in the vat scenario, but when implemented, its absolutely undetectable.