   Why can't we put a Brain in a Vat yet?
  Seems to me that we have all necessary technology to actually make it happen. We have a perfectly safe and artificial compound called Oxycyte which can act as artificial blood combine that with saline, a nutrient solution, antibiotics, and an iron lung. Seems like you could simply cut the brain out, plug it up to the iron lung, connect electrodes to it, and drop it in a sealed vat of saline solution.I know this is obviously way out there but in my opinion it seems possible. Why haven't we done it yet?   
Why haven't we done it yet?Because life is generally considered more enjoyable when you can, you know, move around.  It's hard enough to have an artificial limb; think about an artificial whole body/thread   ;  Obvious solution is obvious:;Obvious solution is obvious:Humans are remarkably well-adapted to living in the real world.  I think that anything that fails to successfully emulate the level of complexity that we experience in our everyday lives will not be sustainable; for instance, the use of recreational drugs can make a person feel euphoria for a limited amount of time, but in the long term it fails to be a substitute for actual happiness, and the person needs drugs just to feel "normal."  Likewise, playing video games is fun.  But playing video games forever, with no chance of escape: also less fun.  Even if virtual reality were to somehow exceed real life, there's no compelling reason you'd need to cut out your brain just to use it; there are seemingly more temporary solutions that would work just as well.   ;  Well, I was going to say maybe it could be useful in certain severe medical surgeries, but it now seems to me that without the brain attached to your body, it would be exceptionally hard to keep the rest of the cells in your body alive.   ;  It's not even possible to replace a single lost leg _properly_, and you want to replace the complete body?Would you like to be the first? ;I know this is obviously way out there but in my opinion it seems possible. Why haven't we done it yet?How do you know we haven't already done it and not told you that's how we're keeping you alive?  Just because we depict technology as inadequate when projecting it into your vat does not mean it is inadequate in real life.I suggest that when offered, you take the blue pill.   ;Seems like you could simply cut the brain out, plug it up to the iron lung, connect electrodes to it, and drop it in a sealed vat of saline solution.Well, the thing is that you cannot just easily connect it. If connecting nerves with other nerves or electronics would be that easy, then a spinal cord injury wouldn't be a big deal either - rather than putting you in a wheelchair for life. Same thing goes for blood vessels. That said, if you don't connect anything at all except for basic blood supply, then it might be possible to keep a brain alive at least for some time (although not very ethical). Head transplants have been successfully performed, although not yet in humans (according to Wikipedia).If we figure out how to reliably connect nerves in the future, along with some other technological advances, then brain transplants will certainly become an option.   ;  If you're talking about a *human* brain, the ethics of this would be very questionable.  It's safe to assume we that we would initially fail at perfectly imitating the nervous inputs a real body provides, and thus that -- even if we could achieve something called consciousness in such a brain, and that's a seriously giant if -- it would be a horrible existence.What would be the point, aside from making my name seem more about medicine and less about philosophy?Would you experiment with it?  I think that in most peoples' opinions that would be no different from experimenting with a brain that was attached to a living body, and we don't usually do that.  If you're suggesting that we do it for medical emergency reasons -- i.e. someone's body is horribly mangled in an accident and we save just the brain to save the person -- you are seriously overestimating our understanding of the brain.  We don't have the capacity to do what you describe.  We don't have anywhere near the necessary understanding of the neural pathways of the brain to do it.   ;  The problem with keeping a brain in a synthetic environment goes well beyond providing a electrical interface and nutrients. Your brain is tightly coupled with the rest of your body through other means, such as hormones, and complex chemical feedback loops from various organs. Basically one must cater for all the variables for a brain to survive in the long term. Even if we manage to get a good electrical interface happening, the brain needs to relearn, or reconfigure its neural networks to work with the new interface. Basically it needs to rewire and undo what it learnt during the first crucial 5 years during childhood... which is incredibly difficult for an adult brain. For instance, you don't see automatically, you learn to see very early on. Therefore, if the optic nerve was cut and wired to something else, the brain may not able to interpret the visual signals as something meaningful, even though the nerve was stimulated properly. The subject may experience flashes of light, but probably not perceive recognisable shapes.That said, the brain can be remarkably adaptable, so who know how far we can go. Impossible? No. Hard? You bet.   