There is a belief that Zen is a philosophy. But it is not. To approach Zen as if it is a philosophy is to begin in a wrong way from the very beginning. A philosophy is something of the mind, but Zen is totally beyond the mind. Zen is the process of going above the mind, far away from the mind. It is the process of transcendence, of surpassing the mind. You can't understand it by the mind, as the mind has no function in it.
Zen is not Vedanta as well because that is a philosophy. Zen is not even Buddhism as it too is a philosophy. Zen is a very rare flowering. It is one of the strangest things that have happened in the history of consciousness. It is the meeting of the Buddha's experience and Lao Tzu's experience.
When Buddha's teachings reached China, a crossbreeding took place. Lao Tzu had given his experience of Tao in a totally non-philosophical way. But when the Buddhist mystics and the Taoist mystics met, they could immediately understand each other heart to heart, not mind to mind. They could feel the same vibe. They could see that the same inner world had opened, they could smell the same fragrance. They came closer and closer and ultimately the two merged into one, giving the world what we call today Zen.
Zen has both the beauty of the Buddha and the beauty of Tao Lao Tzu. That is why Zen is called their child.
Actually, the word Zen has its roots in the Sanskrit word dhyan which itself has been derived from Pali word jhan. jhan became Zen in China.
To understand Zen, one has to make a philosophical effort. One has to go deep into meditation which, by definition, means from mind to no-mind, from thought to no-thought. Mind means thinking, no-mind means pure awareness. And that is it – the ultimate!
(Edited excerpts from Walking in Zen, Sitting in Zen, by Osho, Westland)