Semiotics is concerned with everything that can be taken as a sign. A sign is everything which can be taken as significantly substituting for something else. This something else does not necessarily have to exist or to actually be somewhere at the moment in which a sign stands in for it. Thus semiotics is in principle the discipline studying everything which can be used in order to lie. If something cannot be used to tell a lie, conversely it cannot be used to tell the truth; it cannot in fact be used 'to tell' at all. I think that the definition of a 'theory of the lie' should be taken as a pretty comprehensive program for a general semiotics.