There are two ways of expression. In the West. catharsis has become very important. Encounter groups, Primal Therapy - all believe in catharsis. Dynamic Meditation is a method of catharsis because people have lost the key to sublimate. Patanjali does not talk about catharsis at all. Why doesn't he talk about it? People had the key. the knack. They knew how to sublimate. You have forgotten, so you have to learn catharsis. Anger is there; it can be transformed into compassion, but you have no idea how to do it. And it is not an art which can be taught; it is a knack. You have to do it, and learn it through doing it; there is no other way. It is just like swimming: you have to swim, and err, and sometimes get into danger, and sometimes you will feel lost, the life is lost, you are drowning. You have to pass all those, and then the knack comes, then you know what it is. And it is such a simple thing, swimming. Have you observed? There are a few things you can learn but you cannot forget: swimming is one of those things. Or cycling -- you can learn but you cannot forget. Everything else you can learn and you can forget.