I dont understand this concept. Do you mean that if I am holding a hammer it isn't really what I think it is? or do you mean it in a more radical sense as in I and hammer are not really there?
I think it's an allusion to something in one of the links posted earlier, the Brain in a Jar thought experiment. The idea is that if you feed the brain stimulus whether it's occurring in the real world or not, say swinging a hammer, to the brain, that is indistinguishable from a simulated swinging a hammer stimulus. The brain on its own takes in information and spits out results, essentially.
It's factually true. This is how a person recently manipulated a robot arm using only thought.
I don't have any formal education in philosophy, so I'm sure I'm not saying anything ground breaking, but here goes.
I agree with the above statement that in practical terms, if we have no way to know if what we perceive is real or not, you may as well live the life you want as though it were. But life isn't all about practicality. Here are some things I believe to be true but can't prove. Consciousness seems to be an emergent property of our brain. At some point in the evolutionary family tree, it wasn't required for survival. It is a composite of selected raw input coming from the more basic layer. To me, this strongly suggests existence is completely real because it doesn't require any consciousness to function. I'm borrowing from Steven Hawking's argument against any divine intervention in the current state of the Universe. He said, in a nutshell, that if God created the universe, he completed all his work before the big bag, because from that point forward, no further intervention was needed to get to the universe we see today. (I stand ready to be corrected if I have misrepresented this.)
At the same time, math tells us that according to the holographic principle, the information from a 5-dimensional space can be represented in a 4-d hologram. It's been suggested our universe is one such to account for things like the weakness of gravity in relation to the other fundamental forces. Unfortunately, it's rather impossible for a 4-d person to have any idea what it would be like to be a 5-dimensional being but if this is true, I exist as a 5-dimensional being somewhere. I could be getting this all wrong, but to me this is HUGE, if true. By definition, that 5th dimension would be outside space and time. It could allow ignoring the arrow of time.
Sadly, I think not. When consciousness ceases, you're left with a bag of cells that don't know they're dead yet. It's unfortunate, however, since I would like to live forever. That singularity idea is appealing but I think it's a long way off. In the event it were to become practicable, I wonder if you would eventually forget about your previous corporeal existence?