we want to see things so that we will have confidence in thier existance. seems like a normal thing to want to have happen and everyone will agree that it makes sense to see the "merchandise" as it were, before buying.
but what if our senses are distorting, editing and adding information without us realising what`s going on?
there are many witnesses to accedents on the road yet witnesses are notoriously unreliable due to the fact that people`s bias will add, delete and distort events to fit thier pre-suppositions about what "should" have happened.
a young kid in a sports car hitting a bus will be seen as behaving differently from a businessman in a mercedes by the witnesses.
why does this happen?
because we have memories of prior events stored in our minds that we play to compare with what we just saw so that we can compare events and draw a conclusion. this mechanism is useful if you have had an experience in the past with a lion for instance and you run into one at a gas station or a cocktail party you know that, shit, big teeth and four sets of razor sharp claws means run like hell.........no matter what he`s saying.
so pre-suppositions are useful in some instances but can lead to erronious conclusions when dealing with things that don`t include a lion.