The thrust of koans is to bring you to insight into dharmakaya ("the absolute basis of Reality"). When you achieve that insight you get "spacious mind" , and further koans help refine and root the insight until there can be no fluctuations. At that point you do things like pick up a bowl while holding nothing, etc....
Insight is very similar to faith, as the term is used by the mystics.
If I have faith the size of a speck I can move mountains etc. If I have faith I can heal the sick, trample scorpions etc.
The 3 pillars of Zen are: great doubt, great faith, and great determination.
Doubt
Perhaps I can equate Zen doubt with Christian Hope. I hope what the church teaches is true, I hope Jesus wasn't a madman, I hope I get to Heaven, etc. That is -- I am not sure and I am bothered about it but I will pursue it as if it was true, proven and experienced by me as truth.
Faith
Zen faith is trust in the methods of the tradition, trust in the reliability of the tradition, as well as trust of self -- "Can I do this? Yes I can!"
Christian faith is similar, but it involves faith in Jesus, or better, faith that the hope given by the indwelling of the Holy Spirit is not just a fancy of the church/.
It is v. tenuous: I must have faith that Jesus can bridge the gap between God and my profound doubt - a doubt that transcends fear of death. If I have such faith I will know it is both The Rock and The Ocean. Such faith moves mountains...
But what is it? It is an insight. An insight is an all-pervasive, all-encompassing glimpse into Creation, into Reality, into the ground of being. Without such faith it is hard to imagine martyrdom as joyful. This is love-enabling faith.
Determination
Zen determination is this relentless try-again attitude. In Christianity it may be equated with love (1 Cor. 13). Turn 1 Cor. 13 into situations and it matches well:
- Love is patient = life will frustrate you but you wait in hope-filled faith.
- Love is kind = life is unfair and unkind, brutal and short. But you persevere being fair before unfairness, kind before unkindness, gentle before brutality.
