"the mind's tenderness toward the heart"

I used to be in the habit of writing quotes on paper scraps - things which seemed like truth to me and which I knew I'd forget unless I wrote them down. Yesterday I came across one, and today I found another.

What wisdom is acquired during the course of a life is a result of the mind's tenderness toward the heart.

There it was on a piece of paper, without a source. Looking it up, it is attributed to James Cowan, but since I haven't read his work, I guess I saw it quoted in another place.

Worth sharing.