“I remember when I was a boy we had a common saying: talking to yourself is the first sign of madness. Now obviously if I talk all the time I don't hear what anyone else has to say. And so in exactly the same way if I think all the time that is to say if I talk to myself all the time I don't have anything to think about except thoughts and I'm never in relationship with reality. All right now that's the first basic reason for meditation.”

From: Meditation [Zen and Meditation]