What are the nuances between these three terms for intelligence: 知恵 [ちえ],　知能 [ちのう],　知性 [ちせい]　?


In particular which one is closer to the idea of "ability to reason over
things" as a quality of someone in particular?

What I believe is that 知識 on the other hand is closer to "knowledge" and
"understanding" and 眼識 is more about "discrimination, insight", but as an
intellectual operation, not a property attached to someone, like 認識.




I'd add to @istrasci's answer that:

  * 知能 is more oriented towards mechanical problem solving skills, while
  * 知性 is more about reasoning and discerning abilities only thought to be possessed by humans.

Words like 人工知能 (artificial intelligence), 知能指数 (IQ) show this aspect of 知能.
Also, because of these differences, you will hear more about "動物の知能" (animal
intelligence) than "動物の知性" (animal intellect).

So, "ability to reason over things" as a quality of someone, will likely be
about 知性.




I'd add to @istrasci's answer that:

  * 知能 is more oriented towards mechanical problem solving skills, while
  * 知性 is more about reasoning and discerning abilities only thought to be possessed by humans.

Words like 人工知能 (artificial intelligence), 知能指数 (IQ) show this aspect of 知能.
Also, because of these differences, you will hear more about "動物の知能" (animal
intelligence) than "動物の知性" (animal intellect).

So, "ability to reason over things" as a quality of someone, will likely be
about 知性.

