Logic (9)
(Other definitions for rationale that I've seen before include "Underlying principle" , "Reasoned exposition" , "Philosophy" , "Logical basis (for a course of action)" , "This might account for" .)
'logic' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for reasoning that I've seen before include "Thinking coherently and logically" , "sense?" , "argument" , "Thinking that is coherent and logical" , "Train of thought" .)
'logic' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for reason that I've seen before include "Capacity for rational thought" , "Motive or right thinking" , "Purpose" , "Cause, explanation" , "Logic and rationality" .)