Ching-yuan Wei-hsin, a Chinese Ch'an master, once said this:
Thirty years ago, when having not studied Ch'an, this monk saw mountain was mountains and water was water.
Later, when following the good teacher's guide, this monk...
When beauty is abstracted
Then ugliness has been implied;
When good is abstracted
Then evil has been implied.
So alive and dead are abstracted from nature,
Difficult and easy abstracted from progress,
Long and short abstracted from contrast,
High and low abstracted from depth,
Song and speech abstracted from melody,
After and before abstracted from sequence.