Spirit is the anchor of the set of lots that Paulus Alexandrinus attributes to Hermes: Fortune and Spirit themselves, and then Eros, Necessity, Courage, Victory and Nemesis, each assigned to one of the five planets and each computed not from the Ascendant alone but from Fortune or from Spirit. The set is a small system in itself, in which the two luminary lots supply the foundation and the five planetary lots are built on them, so that the whole is a projection of the planetary order onto the chart. Like Fortune, Spirit is calculated with a sect reversal, one way by day and the reverse by night, and the same is true of the derived lots. That reversal was dropped by much of twentieth-century astrology and has been restored by the revival of Hellenistic technique since the 1990s, which means that older textbooks and modern traditional practice will often disagree about where these points fall.
The reversal is worth stating precisely, because it is the point at which the doctrine of the lots meets the doctrine of sect and the two are often reported loosely. Sect divides the chart by whether the Sun is above or below the horizon at birth. In a day chart the Lot of Spirit is measured from the Sun to the Moon and projected from the ascendant; in a night chart the direction of that measurement reverses. The consequence is that Fortune and Spirit exchange places between a day and a night birth, so a chart cast a few minutes either side of sunrise or sunset can put the two lots in quite different parts of the wheel. Where the sect of a chart is genuinely in question, and near the horizon it often is, both lots should be reported as undetermined rather than one being chosen.