The idea of a dark background consciousness out of which the experiencing arises serves to displace the rigid illusion that that 'you' are the sole source of your experience. The latter is incoherent but nonetheless forms the basis of ordinary life, it is a sort of local minimum hard to escape. Whether there is a background consciousness or not is immaterial, the idea serves only as a lever. There is a kind of knowing of what is prior to experiencing, but consciousness is not the right name for it.