 Things, properties, powers, whatever they may be, if real and causally efficient, must occupy just one location in time (kāla) and space (deśa) and have only a singular nature (svabhāva), by which Dharmakīrti means that nothing real can span, or be present in, several distinct objects over different times and places, and possess the many natures of the various  particulars.[12]  This not only rules out “horizontal universals” (tiryaglakṣaṇa), like blueness, which would have to be present in several blue particulars at one time, but it also rules out “vertical universals” (ūrdhvatālakṣaṇa), or substances persisting throughout time, the numerically identical individual that would be present in each time-slice of a  thing.[13]  It is only series of qualitatively similar moments that constitute what we customarily take to be enduring objects, but there is actually nothing that remains numerically the same for more than one instant.