Zazen or sitting meditation is not without the presence of quietism in which one meets, head-on, the all-too-human world of truck, barter and exchange with, silence and simplicity, abandoning discrimination and rejecting judgement—as much as possible! The belief here is if any kind of practice is to bring us closer to the absolute it might be quietism.
Quietism coming from Taoism certainly had its influence on Chinese Buddhism when it encountered zazen (坐禅), especially in the school of Zen Buddhism which already had a strong introspective tendency through Buddhism's dhyana. Zen taught that, potentially, within our minds is to be found the Buddha and by the purification of our mind one could eventually awaken (buddha) to this mind whose substance is, by nature, pure and bright. But as the practice of zazen or seated meditation became an important part of Zen, in addition to meeting Zen masters for interviews, its true goal was not always upheld. Zazen acquired a kind of promissory element besides quietism in which sitting held out the promise of enlightenment or made the practice of zazen and enlightenment synonymous which appeared to be the case with Dogen's interpretation.
But the mere act of sitting is insufficient to get us anywhere except deeper in the world of delusion. The promissory element of zazen, which seems to say that if we keep doing zazen everyday it's going to benefit us, is still persistent and not easy to set aside. More is needed than just sitting. One still has to make it though Mumon's "gateless gate" which will only happen when we transcend the conditioned Mu which means we see firsthand the Buddha-nature. Buddha-nature, the One Mind, pure Mind, True Mind, etc. are all positive. They betoken a genuine reality.
If one awakens to this reality zazen is much different; it is not like before. Mind is realized as purely animative. It is like a pure light that is directed into the darkness of the psychophysical organism which, in the process, reveals itself and other. This is what is meant by samadhi which means contemplating your original nature which is the eternal Mind according to Zen master Hui-hai. This is also to cease wrong thinking. When we do zazen this way, which is really samadhi, we are increasing the power of our True Mind as compared with the former darkness of our pscyhophysical organism which is all we knew in zazen. It is like bringing a light into a dark cave. This is neither quietism nor is it promissory.