Buddhism denied the reality of consideration, and at the same time it denied the reality of sense perception, but it affirmed the real existence of action at the present moment, and so Gautama Buddha could establish the Buddhist philosophy, which is based on human action itself.
Therefore we can say that Buddhist philosophy is established on the denial of both idealism and materialism, and the practice of Zazen is just the action, which is perfectly different from idea, or matter, but it is just the middle itself.