Experientialism[definition needed] is a philosophical view which states that there is no "purely rational" detached God's-eye view of the world which is external to human thought.
It was first developed by George Lakoff and Mark Johnson in Metaphors We Live By.
Experientialism is especially a response to the objectivist tradition of transcendental truth most prominently formulated by Immanuel Kant which still requires a commitment to what Lakoff and Johnson call "basic realism".
Most importantly, this involves acknowledging the existence of a mind-independent external world and the possibility of stable knowledge of that external world.
[1] In Women, Fire and Dangerous Things, Lakoff expands on the foundations of experientialism with research into the nature of categories.