Arguments are marshalled by the children (7)
I believe the answer is:
reasons
'arguments' is the definition.
The definition and answer can be both related to thinking as well as being plural nouns.
Maybe you can see an association between them that I can't see?
'are marshalled by the children' is the wordplay.
'marshalled' indicates an anagram (I've seen 'marshals' mean this (marshal can mean to gather)).
'by' is a charade indicator (letters next to each other).
'the children' becomes 'sons' (son is a kind of child).
'are' anagrammed gives 'rea'.
'rea'+'sons'='REASONS'
Can you help me to learn more?
(Other definitions for reasons that I've seen before include "Logically deduces" , "Infers logically" , "Debates; thinks out" , "Thinks logically" , "Period of reduced economic activity" .)