  1) Each vocal expression may serve independently from its imposition as a natural sign (De signis, 1978, 86f.) Words indicate for instance the speaker being close, and they may ‘tell’ something about him in the same way as an artwork is indicating the skills of the artist. Furthermore, the spoken word is a natural sign implying that the speaker possesses the concept of the object meant by the word according to its regular meaning. For the significative use of language presupposes the presence of a concept in the speaker's mind that corresponds to the object denoted (De signis, 1978, 85f., Comp. studii theol., 1988, 64). Thus, the relation between the vocal expression and the mental concept is, contrary to what was the common opinion since the days of Augustine and Boethius, not a relation of expression but rather of indexical signification.