In order for there to be a mirror of the world, it is necessary that the world have a form - Umberto Eco

The sign is usually considered as a correlation between a signifier and a signified (or between expression and content) and therefore as an action between pairs. Semiosis is, according to Peirce, "an action, or influence, which is, or involves, an operation of three subjects, such as a sign, its object, and its interpretant, this tri-relative influence not being in any way resolvable into an action between pairs".

Every specific semiotics (as every science) is concerned with general epistemological problems. It has to posit its own theoretical object, according to criteria of pertinence, in order to account for an otherwise disordered field of empirical data; and the researcher must be aware of the underlying philosophical assumptions that influence its choice and its criteria for relevance. Like every science, even a specific semiotics ought to take into account a sort of 'uncertainty principle' (as anthropologists must be aware of the fact that their presence as observers can disturb the normal course of the behavioral phenomena they observe). Notwithstanding, a specific semiotics can aspire to a 'scientific' status. Specific semiotics study phenomena that are reasonably independent of their observations.

The belief that time is a linear, directed sequence running from A to B is a modern illusion. In fact, it can also go from B to A, the effect producing the cause.