 Some logicians have argued that the notion of true future is unacceptable on philosophical grounds or that it is at least unnecessary, since it is possible to establish a semantic model accepting (P5) but rejecting (P3) without involving any idea of a true future. Richmond H. Thomason (1970, 1981, 1984) has formulated a theory based on so-called supervaluations. According to this theory a proposition \(p\) is true at a moment \(t\) if and only if it is true at \(t\) for every chronicle \(c\) passing through \(t\), and a proposition \(p\) is false if and only if it is false for every chronicle \(c\) passing through \(t\). Formally speaking, we may again use the Ock-function to recursively define truth at a moment \(t\) and a chronicle \(c\). Then we may define truth at a moment of time by supervaluating. This means that \(p\) is true at \(t\) if and only if \(\Ock(t,c,p) = 1\) for all \(c\) with \(t \in c\). Future contingent propositions will not meet that condition, nor will their negations, so they are considered neither true nor false. They are “indeterminate” in the sense that they lack truth-values.