“Husserl himself associated the original and basic meaning of the reduction with the mathematical operation of bracketing (Einklammerung). The underlying idea of this metaphor is that we are to detach the phenomena of our everyday experience from the context of our naive or natural living, while preserving their content as fully and as purely as possible. The actual procedure of this detachment consists in suspending judgment as to the existence or non-existence of this content. This by no means implies that we deny or even doubt its existence to the extent of writing it off, as Descartes had done …… To this negative or “bracketing” aspect of the reduction corresponds as its positive complement the possibility of concentrating exclusively on the non-existential or essential content, the “what”, of the phenomena. It is in connection with its positive aspect that Husserl expected the phenomenological reduction to open up entirely new dimensions for phenomenological research”.
the phenomenological movement. a historical introduction by herbert spiegelberg, essentials of the method, page 709. martinus nijhoff publishers 1984, the hague/boston/lancaster.