  Various complications arise in categorizing indexicals as pure indexicals and true demonstratives, or as automatic and discretionary. Kaplan (1989) classifies ‘here’ and ‘now’ as pure indexicals, though he thinks that the temporal and spatial extents of their extensions depend on speakers’ intentions (Kaplan 1989a, 419, n.12). Perry (1997, 2001) thinks that this sort of variation justifies classifying them as discretionary rather than automatic. Other indexicals may raise similar issues. For example, ‘today’ may initially appear to be an automatic indexical in Perry’s sense, but sometimes it is seemingly used to refer to temporal periods longer than a single day, as in ‘Today we ride in automobiles rather than in horse-drawn carriages’. For further discussion of these distinctions, and their viability, see Mount (2008).