In sections 96-97 of the Hegel’s Phenomenology, he describes the growth of sense (meaning both sense as the sensory and sense as meaning) for consciousness. In the challenge of sense develops the famous pattern of (1) thesis, (2) antithesis (problem, contradiction), then (3) synthesis of multiplicity. The key concepts of “negation” and “mediation” also appear, which will recur throughout the dialectical thinking of the Phenomenology.
In 96-97 the sense of “now” for consciousness grows out of being first attached to one sense (night = now), then that sense being negated by an other (night = not-now, day = now, night = then), so that the meaning of “now” must then grow, organically, so to speak, to involve multiple, differing senses (now = day + night, or neither, i.e. I gain the freedom to use “now” to mean neither day nor night but some more-specific sense, just this moment).
Thus “now” — meaning the present — and its opposition or other, “then” — meaning the past or future — provide the negation or limiting condition (the “not-“) to each other. But precisely in their “negating” (being-not the other) they also provide a positive sense, a positive mediation, the meaning or grounding to each other, i.e. a condition of possibility for the other to appear as such.
Here we get the meaning of appearing in Hegel’s sense of the term for phenomenological science: not only “appearing” as the problem of having to discover the truth about something hidden or unknown to us (as in the natural sciences), but appearing as the positive growth or becoming of a new consciousness of the world (as in the humanities and philosophy).
Phenomenologically, “we” (the phenomenological observers of the struggle of consciousness) can now see the resulting multiplicity in the sense of “now” (opening to “then” include other moments) growing directly out of the experience of consciousness trying to maintain a coherent sense of meaning to “now” (for itself) in the face of a constant flux of changing sense experiences.