All present for this subject? On the contrary (7)
I believe the answer is:
history
'all present for this subject? on the contrary' is the definition.
'history' can be an answer for 'subject?' (history is a kind of subject). I'm unsure of the remainder of the definition.
'this subject? on the contrary' is the wordplay.
I cannot really see how this works, but
an anagram of 'this' is 'hist' which is located in the answer.
The remaining letters 'ory' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for history that I've seen before include "'... repeats itself'" , "Chronicle" , "eventful past" , "Time passed" , "Life story" .)