Since /lit/ could not help me I might as well ask here: What is considered reality, how can we assess something to be real? As an example, if someone claims to see ghosts, the majority would consider him insane but if someone was born blind he would call us insane too after hearing our concept of colors. I believe this to be a philosophical question, shame that /lit/ wasn't helpful in that regard so maybe someone could shed some light on that topic in a scientific view.