One who philosophised on what comes from the east (5)
I believe the answer is:
hegel
'one who philosophised' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'on what comes from the east' is the wordplay.
'on' says to put letters next to each other.
'what' becomes 'eh' (sound used to ask 'what?' or 'pardon?').
'comes' becomes 'leg' (I can't explain this - if you can you should give a lot more credence to this answer).
'from the east' says the letters should be written backwards (on a map from right to left).
'eh' put after 'leg' is 'legeh'.
'legeh' backwards is 'HEGEL'.
Can you help me to learn more?
(Other definitions for hegel that I've seen before include "Georg Wilhelm ---, Ger. philosopher" , "German 'dialectic' philosopher" , "German philosopher, d. 1831" .)