 Regarding the temporal extension of real particulars, momentary entities pose a challenge to transactional usage: once known, they have already ceased and hence cannot be used nor acted upon. Transactional usage is better grounded in objects that have some duration. Continua, however, bring about the same critique as macroscopic objects: what really exists is a particular at each moment, but the chain of causally related moments, even though it may appear to the ignorant mind as an object having duration, only exists nominally. A limited temporal extension is not an option, for, in difference to aggregated atoms, the different moments in a series do not co-exist—only the present one exists and is causally efficient; they hence cannot be considered to contribute collectively to the cognition of an object.