The following is a quote from Horse Medicine, a very interesting and controversial book about Zen Practice in Paris in the 70's under the guidance of the late Zen Master Taisen Deshimaru.
"Mountains, rivers, sun, moon, stars, the big land, mind-land, treasure land and the heatless pond (i.e. nirvana) are actualization of mind," says the master.
"All these lands are based on the experience of satori and are therefore manifestations of shiki soku ze shiki.
Mountains, rivers etc... are seen differently by heaven people and by earth people, when you attain satori the viewpoint of mind becomes universal and all existences become one mind..."
"Is it outer phenomena actualized from our inner mind or is the actualization of our inner mind coming from the outside? And when we are born is another mind added, and when we die does this mind escape?...
"All the cosmos is one-mind. All existences are the actualization of self-mind. So how should we think when we study mind ? Usually we think of natural phenomena: Mountains rivers sun moon etc... as outside our mind. But these are mind itself."
"Do not deduce from this that everything is only inside your mind. Abandon notions of outside or inside, coming or going. Undivided mind is not outside or inside. It comes and goes freely without attachment. Every thought is independent, newly created, vital and instantaneous. So please," the master enjoins us, "repeat this method of thinking, and form it, build it into your daily life with only the one mind of the Three Worlds."
This is deep stuff and we could discuss and argue about it for a very long time. But it really is not the point, because discussion and argument can never take us very far. The point is the last sentence : "Repeat this method of thinking, form it, build it into your daily life,,,"
In other words : Train
In Zen and Budo, Discussion and Argumentation are a waste of time and energy. Only action matters.
We can train our minds in the same way we train our bodies. Actually, it is the only way we can change anything.
And training is based on repetition. If we want to get better at Karate, Piano, Kendo or Math, we train, we practice, we repeat, times and times sequences of moves, of notes, of reasonning. It is boring at times, but it works, and actually there is no other way. Same with the mind.
Practice...
Note :
If you believe there is much more to Life and Zen than making people happy and comfortable around you, then read "Horse Medicine". If you believe that leading a morally, socially and politically correct life is of the highest importance, you probably won't like this book. Zen is not comfortable.