that would leave no achievements or knowledge really.....
take away all our material possessions and we return to the very basics of being a human - the hunter gatherer lifestyle. knowledge will rarely help you there, only experience will help.
that being said, what are we? we are animals. we are the instinct we all naturally have from our history as hunter gatherers and warriors. how much do you know about yourself if you've never been in a fight? you don't know anything.