Mind/matter duality

[little_monkey]

My evidence is that physics is an objective system of explanation, and must therefore depend only on what is actually observable. Brain function IS observable by others-- subjective experience ISN'T

Don't believe me? If you are in fact sentient, prove it. Take any lab experiment in which brain function is linked to consciousness and prove that the person whose brain it is is actually experiencing, rather than just saying they are..

For example, let's say you ask someone to move a limb. The outside observer can indicate brain activity associated with decision-making and movement, nerve and muscle activity, etc., resulting in the moving limb. The subjective observer indicates experiencing a decision, and the sensations of movement – although how exactly the decision takes place is not observable to them.

The subject of intentionality is no different. The outside observer can identify brain activity associated with intentionality. The insider has the subjective experience of intentionality but is not aware of the subconscious brain activity that gives rise to that process. It doesn't follow that the emergence of intentional state or acting upon intentional thoughts directly arise from that subjective state, and at no point is it necessary to conjecture the existence of some sort non-physical stuff.

It's great to take the philosophical position that other minds than mine exist, but this is not a scientific conclusion-- it's an exercise in pragmatic philosophy. And when you are required to make a philosophical assumption to do science, you don't get to use science to validate that assumption-- circles are circles, no matter who's running in them.

It would be difficult to maintain the theory that we are brains in vats when 7 billion people can describe a falling body, well, as a falling body. You would have to postulate a computer larger than the galaxy to maintain for each of those 7 billion people the same illusion for each second, 24/7 for the rest of human existence. A simpler hypothesis is that we are individual perceiving a common reality - falling bodies, cars crashing, etc. It is on the interpretation of what we perceive that we will disagree -- why is that body falling, who made the car to crash, etc.