Spirit (n.) in its primary signification is breath.
Spirit (n.) without bodies must somehow read and hide each other's thoughts without words — a power we must suppose and cannot picture at all.
Spirit (n.) above us are probably more numerous in species than the material creatures below us, since the visible world descends in a continuous series without gaps.
Spirit (n.) of the finite kind are no more known to exist by our idea of them than fairies or centaurs are by ours, and their existence rests on the evidence of faith.
Spirit (n.) separate from bodies surely know corporeal things far better than we — but how, we have no idea at all, since our knowledge reaches no further than our own ways of perception.
Spirit (n.) of superior rank are happy in seeing at one glance the connexions we hunt out by single slow steps, poring in the dark, forgetting one proof before we have found the next.
Spirit (n.) is no more obscure than matter: we know the substance of neither, so denying spirit for want of a clear idea would be as rational as denying body.