Definition of "extramental"

He [Martin Heidegger] was influenced by Edmund Husserl, a German thinker born in 1859 who was soon to become the leading figure of the phenomenological movement, dedicated to the description and investigation of our conscious experience without reference to its extramental causes and consequences.

2014 April 12, Michael Inwood, “Martin Heidegger: the philosopher who fell for Hitler [print version: Hitler's philosopher]”, in The Daily Telegraph (Review)‎, London, page R10