noun
An abstract noun for being in accordance with reason, logic, or sound principles. In everyday writing, 合理的 is often used for 'rational' and 合理性 for 'rationality as a quality,' while 合理 itself appears in more abstract contrasts such as 合理と非合理.
合理と非合理の境界は、いつも明確とは限らない。
The boundary between rationality and irrationality is not always clear.
この議論では、感情よりも合理が重視されている。
In this debate, rationality is valued more than emotion.