However, this makes it hard to specify adequate truth-conditions for This is M. 19.
Insisting on both adequate truth-conditions and adequate exemplification conditions might help narrow down the field of candidates.
It thus has been argued to fail to achieve a fully adequate theory of truth.
Tarski's theorem shows that, in the setting of first-order arithmetic, it is not possible to give what Tarski considers to be an "adequate theory of truth".
The acceptance of a theory involves only the claim that it is empirically adequate, not its truth on the theoretical level.
The central question then becomes: How may the formal setting or the requirements for an adequate theory of truth be modified to regain consistency — that is, to prevent the liar paradox from trivialising the system?
Given this semantical machinery, Tarski can solve in the negative the problem of the existence of (a formal counterpart of) a universal language, i.e., one where it is possible to define an adequate notion of truth for the same language.
Inquiry seeks truths, or at least empirically adequate representations, but which truths any particular inquiry seeks depends on the uses to which those representations will be put, many of which are practical and derived from social interests.
A fundamental concern about the semantical treatment of vague predicates is whether an adequate semantics should be truth-functional, that is, whether the truth value of a complex formula should depend functionally on the truth values of its subformulas.
Conversely, modern philosophy, beginning with Descartes, appreciated the value of subjectivity as a philosophical starting point but failed to develop an adequate notion of objective truth.
