The Bourne Condition (7)
I believe the answer is:
amnesia
This clue could be a double definition.
'the bourne' is the first definition.
The answer and definition can be both related to thinking as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'condition' is the second definition.
(I have seen 'Mental condition' mean 'amnesia' so perhaps 'condition' could also mean 'amnesia')
Can you help me to learn more?
(Other definitions for amnesia that I've seen before include "Disorder" , "Asia men with memory loss (7)" , "memory problem" , "Main sea (anag.)" , "illness" .)