But the purpose of Zen is not meditation.
It seems many people misunderstand it.
Zen is the part of Buddhism, but I can say Zen have more independence even inside of Buddhism.
In Buddhism, there is no GOD unlike Christianity, Islamic and Judaism.
Because, originally, Buddhism is the way of mental training, not for salvage our spirit. Actually, lot of my foreigner friends training Zen. Some of them are Islamic, some of them are Christianity. Zen is trained even in Vatican and NASA. Zen does not blaspheme their faith.
There is a one example.
When you sit on the seat of restaurant, waitress serve a glass of water (in Japan, water is basically free). Then, you grasp the glass and drink it. At that time, do you really drink it? Unfortunately, it is very difficult drink it.
When you grasp the glass, your arm muscle estimate the weight. In short, brain refer to past experience for estimation. When you grasp the glass, your brain already have estimated the temperature of the glass. When you drink the water, your tongue already have estimated the taste of water.
Therefore, I say that you can't taste current now sense.
Many people look back at the past experience for the future action.
But we can live only "NOW". We can't change the past, we can't know the future even after one second. But somehow, we can't control our brain. We can't delete our memory by our mind. Also, it is not easy to stop guessing the future. These are brain problems. Zen train our mind instead of brain. Zen is the way of mind training.
If you cut the past memory and future guessing, you will feel even the moon in the sky is so beautiful. I think that is the purpose of Zen.
In western countries, traditionally "why" is the most important keyword for any kind of practice. In Zen philosophy, why is just why. You can't know it, but you can be it. No worry, even if you can't know it, you are it already.
Well, I think I talked too much. One of main philosophy of Zen reprove as "Not by written letter".