noun
essence and fringe; root and branch; means and end
Used in philosophical or analytical contexts to contrast the fundamental and the peripheral, or the essential and the incidental. Often appears in the set phrase 本末を転倒する (to put the cart before the horse).
本末を転倒してはいけない。
Don't confuse the means with the end.
彼の議論は本末をわきまえていない。
His argument doesn't distinguish between the essential and the incidental.