The most common and most likely answer to this crossword clue is the 8 plus 7 letter word BERTRAND RUSSELL
I've seen this crossword clue in The Daily Telegraph
B
E
R
T
R
A
N
D
R
U
S
S
E
L
L
More clues leading to the result BERTRAND RUSSELL
Buddy explains!
The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.