From The Huge Entity:
As ‘You’ Like Itby Jaime Morrison
don’t take this personally but your depth of sensation, though perhaps impressive echoing as it does in the enclosed space of your own mind, is stunted. comically so in fact. your five senses, on which you rely totally, are capable of offering you only the tiniest subset of the total information available for you to process. your mind unceremoniously filters out large segments of this already reduced sensory payload immediately upon arrival and interprets the fractional amount of data remaining. this mind of yours is a dynamo of hubris, presumptuously drawing all manner of conclusion with only the most circumstantial evidence. were it a prosecutor its case would be thrown out. and yet this mind of yours has the audacity to tell you what “reality” is and what “you” are.
this might be a bit embarrassing if “you” actually existed.
but i do exists! and how dare you insinuate otherwise?!
well, then, by all means prove it. you have the floor.
look at me! i’m tearing a phone book in half! i’m going over niagara falls in a barrel! i’m stomping on an ant! yeah, i’m crushing an ant under my heel. ask him whether i exist or not!
ah yes. that machine which is your body… it would seem a great ally when seeking to prove your existence – but then we’re not really talking about your bones and spleen and nostril hairs here are we? or do you consider your physicality to be interchangeable with your “self”?
well, not exactly…
good. because while you are running for office and reading poetry and murdering a stranger in an alleyway, your body is busy with other matters, like keeping your blood oxygenated, doling out nutrients, and making sure you don’t walk into any blazing fires; that kind of thing. truth be told, your body is probably not all that interested in the trifles “you” are. your body’s got work to do.
More here. (Including the other 10 reasons you don’t exist!)