There's evidence that your brain is influenced by e.g. certain chemicals in your bloodstream produced by gut bacteria.

https://www.theatlantic.com/health/archive/2015/06/gut-bacte...

So the brain in a jar model where the only interface with the real world is through nerves is most probably wrong; now your jar also needs a stomach with a fully developed microbial ecosystem. And that's just one recent mechanism that was investigated; there are probably many others.

No, at most you can say it requires a way to introduce those chemicals into the bloodstream in the brain.

Actually, all you need is a way to stimulate the same receptors that are stimulated by those chemicals.

Just as with unit testing, you don't actually need to hook up your SUT to a real environment, you just need to hook it up to something that will exercise the same interface as a real environment.

Indeed. I over-simplified - but whatever the mechanism people refer to it's mockable.

Yes, but it doesn't follow that the computation necessary to generate the mind is infinite or impossible to isolate.

If you are a brain in a jar, then all that evidence is simulated.

It's just another attached input device.

The simple and scientific answer is that you are not a brain in a jar.

Its a mind body system, as much if not more than it is just a mind + body.

The you who makes decisions on a hungry stomach, is a very different person who makes decisions when satiated, and so on.

>The simple and scientific answer is that you are not a brain in a jar.

The question is just about simulation. Brain in a jar is an arbitrary thought experiment (Kant's(?) evil genius, or indeed "The Matrix" if you prefer) about how you can be sure your environment is real.

In this there's no information assumed about what is real, just that I'm a unit (brain) processing input (electrical impulses/chemicals/whatever) which are fed to me from a source (unknown). For you to say "you just aren't" and then rely on evidence from the very systems that are being described as compromised is to miss the point.

Don't bring "simple and scientific" to a philosophy fight.

But why do you consider the brain (and presumably no more or no less than the brain) to be the vessel for your self, rather than other boundaries of embodiment?

You can choose an arbitrarily large vessel (e.g. you can argue that you are your body + your immediate surroundings). But the brain seems to be the smallest such vessel which still leads to an indistinguishable result.

We know from neurosurgery that some fairly large parts of the brain can be removed without apparently adversely affecting the subject's sense of self, so it seems it must be more complex than drawing a boundary around the gross anatomy of the brain.

Assuming nerves "stream data" and neurons "process data". Also, who is the you that is doing this streaming and processing?

"You" is not an atomic Unit.

Think of it this way. When you type something to google, what is the "Google" that is answering your question? "Where" is it?