Compassionate article penned by philosopher (6)
I believe the answer is:
humane
'compassionate' is the definition.
('humane' can be similar in meaning to 'compassionate')
'article penned by philosopher' is the wordplay.
'article' becomes 'an' (indefinite article).
'penned by' means one lot of letters goes inside another.
'philosopher' becomes 'hume' (I've seen this in other clues).
'an' put into 'hume' is 'HUMANE'.
(Other definitions for humane that I've seen before include "Compassionate, benevolent" , "Kind and civilised" , "Benevolent and merciful" , "Kind-hearted and compassionate" , "Kind - compassionate" .)