Scientific statement the more complicated (7)
I believe the answer is:
theorem
'scientific statement' is the definition.
(a theorem is a proven statement or proposition)
'the more complicated' is the wordplay.
'complicated' is an anagram indicator (a complex or confusing ordering of the letters).
'more' is an anagram of 'orem'.
'the'+'orem'='THEOREM'
(Other definitions for theorem that I've seen before include "speculation" , "Demonstrable proposition" , "Deduced formula" , "The more it changed to a proposition to be proved" , "this has been established" .)