Ways to say it
| Japanese | Romanization (Wiktionary) | IPA |
|---|---|---|
| 思慮 | shiryo | [ɕiɾʲo̞] (narrow) |
| 理致 | richi | [ɾʲit͡ɕi] (narrow) |
| 理性 | risei | [ɾʲise̞ː] (narrow) |
In Japanese, the translation for 'reason' depends on whether you are referring to the human faculty of rational thought, the underlying logic of a situation or the quality of being prudent. For the abstract capacity for rational thought, use 理性. For the underlying principles or logic of how things work, use 理致. If you mean thoughtfulness or careful judgment, use 思慮.
What does it mean word for word?
The word 理性 is composed of 理, meaning logic or reason and 性, meaning nature or quality.
Which one should you use?
The three main forms serve distinct purposes: 理性 is the most common term for the human capacity for rational thought, often used in philosophical, legal or psychological contexts. 理致 refers to the underlying logic, principle or the 'reason why' something is the way it is. 思慮 refers more to the quality of being prudent, thoughtful or having careful judgment rather than the abstract faculty of reason itself.
How does it change in a sentence?
To use the concept of 'reason' as an adjective (for example, 'a rational person'), you can add the suffix -的 to 理性 to form 理性的.
How do you pronounce it?
shiryo
Did you know?
- The kanji 理 used in 理性 originally referred to the pattern of veins in jade and the act of carving those veins to make a ornament.
- Japanese distinguishes between 理性 as the faculty of reason and 理屈, which refers to the 'reasoning' someone uses to argue or make excuses.
- In a business or formal setting, if someone's behavior lacks 'reason' or common sense, they might be described as 道理に合わない (douri ni awanai), literally meaning 'does not fit the path of reason'.
Examples in context
- すべての人間は、生まれながらにして自由であり、かつ、尊厳と権利とについて平等である。人間は、理性と良心とを授けられており、互いに同胞の精神をもって行動しなければならない。All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.This sentence is useful for showing how human beings are endowed with the faculty of 理性.Tatoeba #475434 by e4zh1nmcz, translation #338182 by sysko
- 恋愛は理性では抑えられない。Love is beyond reason.This sentence illustrates the concept of love being beyond the capacity of 理性.Tatoeba #77437 by mookeee, translation #326282 by Dejo
- 理性を失った人たちが戦争を遂行した。Men who were bereft of reason conducted the war.This sentence shows the consequence of people losing their 理性.Tatoeba #78374 by mookeee, translation #325342 by AlanF_US
- 彼女が遅れた理由を教えてください。Please tell me the reason why she was late.
- 交通事故の原因は速度超過です。The cause of the traffic accident is speeding.
- なんで休んだの？理由を教えてよ。Why did you take a day off? Tell me the reason.
- なるほど、それは納得のいく理由(わけ)だね。I see, that's a reasonable reason.
- なぜ彼女が怒っているのか、理由を尋ねてみましょう。Let's ask about the reason why she is angry.
- 明日は試験だから、勉強しなくてはいけません。Since there is an exam tomorrow, I have to study.
- 3 more sentences on Tatoeba
Example conversation
Ren and Himari are discussing a difficult philosophical topic in a cafe.
- 蓮 Ren思慮深い判断が必要な時もありますね。Shiryo bukai handan ga hitsuyo na toki mo arimasu ne.There are times when thoughtful judgment is necessary.
- 陽葵 Himari確かに、思慮を欠くと失敗します。Tashikani, shiryo o kaku to shippai shimasu.True, if one lacks reason, one will fail.
- 蓮 Ren陽葵さんはいつも冷静ですね。Himari-san wa itsumo reisei desu ne.Himari, you are always calm.
- 陽葵 Himari蓮さんの考え方に学ぶことが多いです。Ren-san no kangaekata ni manabu koto ga oi desu.I have much to learn from your way of thinking, Ren.
Sources
- Wiktionary, “reason” translations and entries 思慮, 理致, 理性, CC BY-SA 4.0, dump of 2026-09-26.
- Example sentences: Tatoeba CC BY 2.0 FR.
