Philosophers met crisis, being confused about Greek character (11)

'philosophers' is the definition.
(empiricist is a kind of philosopher)

'met crisis being confused about greek character' is the wordplay.
'being confused' indicates an anagram.
'about' means one lot of letters goes inside another.
'greek character' becomes 'pi' (letter from the Greek alphabet).
'met'+'crisis'='metcrisis'
'metcrisis' with letters rearranged gives 'emricists'.
'emricists' enclosing 'pi' is 'EMPIRICISTS'.