What is real is based on the common consensus of what others perceive as reality. Some people are exceptions to this because of an inability to know the world around them. This would be the case in people who are color blind and can not see colors the way others do. There are also other reasons to exclude people from the common consensus such as mental illness or drug use because they fail see the world as what is considered normal.
I do admit that there is a slight chance that nothing is real and that we are much like avatars in a vast computer simulation but the likelihood of that being true are so slim that it has virtually zero chance of being true.
Either way, we must accept the common consensus as being reality. Without accepting that, we have no place in reality and are likely to be a threat to others as well as ourselves. A person who feels the world around them is not real should be locked up for the safety of others as well as their own safety. If a person does not feel the world around them is real then they may kill someone with no more thought that taking off a pair of shoes, and may also feel that they also are not a part of reality and in order to see the real world they must kill themselves.
What happens if you jump from a plane, at 10,000 feet, without a parachute? Chances are, you will die. What happens if you stick your hand in the fire? You get burned. What happens if you hit you thumb with a hammer? It freaking hurts! Our entire universe is cause and effect. This is reality. It is absolute. It is universal. If you claimed that you didn't exist, I would stick you with a needle, then comment on how someone who doesn't exist can yell so loud. Yeah. It's real.
Socrates once asked a man by the name of Glaucon to imagine a cave.
In this cave, prisoners had been made to face a blank wall, and were chained, so they could not move from this viewpoint. An elaborate puppet show was built behind them, and a large fire cast light onto these puppets, throwing their shadows on the walls for the prisoners to see. These dancing shadows are the entirety of these prisoners lives, and, naturally, they begin to assign value to them, naming them, giving them definitions and character. Attempting to establish their entire view of the world from only shadows of puppets in a cave.
This is an excellent description of the human mind, and our willingness to assign subjective conclusions from our sensory input, and how potentially faulty that could be.
Often people bring this up in support of the statement that we can never truly know if reality is real or true. For all we know, we might be watching shadows flicker on a wall, unknowingly chained by our own assumptions and base sensory input.
People seem to forget though, there's a greater reality at play, even within the confines of this allegory.
Yes, these men are chained to the walls watching shadows. But the shadows will ALWAYS behave predictably.
By this I mean the laws of physics, of how light behaves will never change.
No matter how I wish to believe I may jump and continue until I'm flung into space, it won't happen.
I could believe completely that if I put a gun to my temple and pull the trigger, the bullet will pass through me harmlessly. This will, however, not be the case.
Our impressions of how the world MAY be are dashed hopelessly against reality, time and time again.
There are certain rules of the universe we have come to understand as absolute, and as we learn more, though our reality may change and evolve as we ourselves become wiser, it will not become something new entirely.
With that said, we know that there is a greater reality that is inescapable, no matter how we may squirm to avoid it.
The day that physics, chemistry, biology, and the pillars of our continued existence become unpredictable is the day I'll call reality into question.
This was an excellent question, by the way.
If reality is real then the laws are of reality we have observed are real there would be no afterlife, no alternate lifetimes, no reincarnation it would be the end of all of you and if you could even fathom the answer then the would be no as you shouldn't be able to function.
I say that reality is the common consensus of what is perceived as real. Though someone who is mentally ill or under a drugs influence may perceive reality different, they would be the exception to common consensus like a color blind person is unable to see the colors as people with normal vision. It is because of such distorted views some people can not be considered in the common consensus of what is real.
Though it is vague "what if" possible that all reality is not real and that we are just avatars in vast computer simulation, this is far fetched idea with almost no chance of being true.
Either way, the reality that we know must be considered reality, because otherwise we would have nothing to base ourselves on and to interact with. If you choose to believe in some fantasy world instead of what others view as reality then you have no place in reality and should be locked up for the protection of others as well as yourself. People who do not see the world as a real place tend to treat people as if they are less than real. This could easily result in killing someone with no more thought than taking off ones shoes. They may also feel that they are also not real and feel in order to see the real world they must die in this reality.
The entire problem with the concept of reality is that it's a concept and the terminology that humans have is insufficient to be able to adequately answer this question particularly because all definitions of "Reality" fall short and are too distinct to encapsulate reality itself. I guess what I'm saying is we're just not powerful enough to be able to do so.
I want to start by saying 2 things:
1) I am a firm believer in science and evidence and aren't arguing some gooey conspiracy theorist "we're in the matrix" crap.
2) I do believe that our perceptions of reality are close to accurate, just not quite exactly spot on.
Numerous research has gone into the area of perception and cognition of reality. Studies continuously show that every individual perceives events slightly differently.
Perception is based upon the processing by our brain of information taken in by our body. This information is stored as memory. Memories become distorted to varying degrees. It may be that you didn't observe the situation for long enough. It may be that your past experiences are shaping the way you react to an event and your memory changes accordingly. It may be that you haven't accessed these neural pathways for a prolonged period of time, leading to the degradation of the memory.
Ultimately, every individual perceives and then stores "reality" in a different way". In reality, there is no reality. We can't ever truly be objective observers. Our brain interprets information, it doesn't take in precisely what is occurring. For this reason, we can't ever know if reality is real, as we can't determine perfectly what reality is. Reality is subjective. To the furtherest possible extent, it is only real to us.
How do I know this isn't a dream I will wake up from? Or maybe this is a state of delirium or dementia and the real me is drooling and mumbling nonsense strapped down in a hospital bed in the real reality. Or I could be enjoying (for the most part) an intense drug trip, some partakers of salvia have reported experiencing an entire lifetime thinking it was real within the short 5 minute trips it provides thanks to time-distorting effects (they are typically mostly just stationary or just laughing for these 5 minutes). I could be playing a video game made from technology which in the video game world has yet to be invented (virtual reality technology that creates the illusion that the virtual world is the real one).
Science can't even prove it ever, since everything I or anyone knows about science has to be known by using one's mind. If one's mind is somehow being tricked into thinking a false version of reality is reality then one would have no way of knowing.
And what will I do about it? Nothing. If the world isn't real then I'll enjoy this fantasy world, if it is real then I'll live in this real world. Whether I believe this is the real reality or not has no bearing on the actions I should take within this perception(which may or may not be reality) that I experience. Still interesting to think about.