 Moreover, Davidson (1979, 1984) stressed that no conventional sign could work as a force indicator in this sense, since any conventional sign could be used (and would be used) in insincere utterances, where the corresponding force was missing, including cases of deception, jokes, impersonation and other theatrical performances. Basically the same point is made by Bach and Harnish (1979: 122–127). If Davidson, and Bach and Harnish are right, then conventions are also not sufficient (but see Kölbel 2010 for an argument against this view).