According to Zen man is of the nature of Buddha; he is perfect, nothing is lacking in him. But he does not realize this because he is caught in his entanglements of his mental representations. Everything happens as though a screen were woven between himself and Reality by his imaginative activity functioning in the dualistic mode.
Imaginative mental activity is useful at the beginning of man’s life, as long as the human machine is not completed, as long as the abstract intellect is not fully developed; it constitutes, during the first period, a compensation without which man could not tolerate his limited condition. Once the human machine is entirely developed, the imagination, while still retaining the utility of which we have just spoken, becomes more and more harmful; it brings about in fact a wastage of energy which otherwise would accumulate in the interior of the being until the crystallisation of intuitive non-dualistic knowledge (satori).
from Zen and the Psychology of Transformation: The Supreme Doctrine.