According to Geach, since any act of pointing is ambiguous, someone who baptizes an object by pointing to it must apply a sortal properry to disambiguate his reference and to ensure correct criteria of identity over time for example, someone who assigns a reference to 'Nixon' by pointing to him must say, 'I use Nixon as a name of that man', thus removing his hearer's temptations to take him to be pointing to a nose or a time slice.