"And something very unusual happens. That fixed behavior--which is rigged and stereotyped and usually ends up with a meal--changes. ... And an incredible ballet begins. ... They are beginning to do something that neither would have done without the play signals.""John mentioned that I've done some work with murderers."
"It doesn't have a particular purpose, and that's what's so great about play. If the purpose is more important than the act of doing it, it's probably not play."
"[M]anipulation of objects is the hand in search of a brain. The brain is in search of a hand, and play is the medium by which those two are linked in the best way."