I think I have mentioned before on this blog site that I learned - had my attention drawn to - an interesting piece of information, or actually observation, from my university Philosophy 101 professor: that all you really know is what you have actually experienced yourself. So, yes, you can assume that the Hawaiian Islands are where we are told they are, because so many people have verified that fact; but if you haven't actually been there, you don't really know. And even of things that we ourselves have 'experienced,' we don't necessarily really know that they are true. They could be just made-up imagery; things outside of ourselves, that our senses pick up on, but only as imagery effects. Our senses, then, can be 'victims' of deception.
Some cases in point noted below.
from the exohuman site - An 'alternative' report on the Boston Marathon 'Massacre' - Apr. 22-23