This all comes down to how we percieve the world, either with our sense data, like empiricists would say, or like bishop berkley would say: all that exists are our minds and our ideas. His idealism rests on the existence of god though which masquerades as an explanation but really explains nothing. The thing about sense data, the images we get in our mind when we see things. Like a table would be a rectangular hard piece of sense data and a melon would be a round yellow patch of sense data. Well, the thing about sense data is that it's private and it's subjective, we can't compare our sense data to others. When I look at a tree and you look at a tree we would see something different, especially if it were in our imaginations. As Wittgenstein would say something that's private can not be checked from an external source, therefore rendering it meaningless. What was my point again? Oh yeah, ganja is good :stoned: