理性

• Reading: りせい
• Romaji: risei
• Kanji breakdown: 理 (ri) — reason, principle; 性 (sei) — nature, faculty
• Pronunciation: /ɾiseː/

Meaning

Reason; rationality; intellect. The faculty of logical thinking and self-control that governs behaviour.

A noun referring to rational thought as opposed to emotion (感情) or instinct (本能). 理性的 (rational, reasonable) is a common adjectival form. Losing 理性 implies acting on impulse or passion rather than judgement. A central concept in philosophy and everyday moral discourse in Japan.

Examples

1. 激しい怒りに駆られながらも、彼は理性を保った。 Despite being driven by intense anger, he maintained his reason.
2. 理性的な判断がこの局面では不可欠だ。 Rational judgment is indispensable in this situation.
3. 感情と理性のバランスを取ることが成熟した大人の証しだ。 Striking a balance between emotion and reason is the mark of a mature adult.

Usage Guide

Context: philosophy, psychology, ethics, daily life

Tone: reflective

Origin & History

A Meiji-era translation of the German Vernunft and Latin ratio, introduced during the adoption of Western philosophy. From 理 (principle, reason) and 性 (nature, faculty).

Cultural Context

Era: Meiji–Present

Generation: All ages

Social background: Universal