We need absorption in order to refine. In order to see our limited self we must, if only temporarily, step out of our limited self. If we never step out of our limited self, then surely all we know is limitation.
Before awakening and absorption, we perceive self as an arising and subsiding field of limited, conditioned and temporary phenomena; we see something, we think something, we hear music, we taste food. All activity arises and subsides. Everything that is bound to arise within our current experience is seasoned with the same flavours of duration, separation and limitation.
Through absorption, we momentarily step out of that field. We step into a space that, for our current mind, seems to be unconditional, timeless and unitive. Through this, we realise that all of our experience that seems limited is contained within and is permeated by the unlimited, the unconditional, the eternally free. We see that our conditional reality is actually made of the unconditional. Somehow, miraculously, this apparent reality-creation is woven out of pure space and nothingness.
Each time we go into absorption, we bring a piece of it back with us. A perception of life previously limited becomes pierced by the source. Our lived world slowly becomes permeated by the flavours of equanimity, stillness and contentment. Once permeated, the expanded experience is prominent. Once prominent, the limited mind is simply overwhelmed.
Absorption is the central spiritual practice because it is the only means by which we can refine our core perception of the reality and rediscover the root of our very own being. We may be told to embrace this and that spiritual quality, or embrace selflessness and simplicity, but in fact these qualities become actualised naturally when we begin to understand the essence of what this reality actually is. This all happens through absorption, and through a gradual refinement of perception that allows us to establish our fundamental self-identity on a deeper and more wholesome level.