 With this new modality, one can provide syntactic definitions for the concepts described above. Indeed, while the formula \(\lambda_0 := [&lt;]\bot\) characterizes the most plausible worlds (so \(K (\lambda_0 \rightarrow\varphi)\) expresses that the most plausible worlds satisfy \(\varphi\), just as \(B\varphi\) does), the formula \(\lambda_1 := \lnot \lambda_0 \land [&lt;]\lambda_0\) characterizes the next to most plausible worlds (so \(K(\lambda_1 \rightarrow\varphi)\) expresses that the next to most plausible worlds satisfy \(\varphi)\). This procedure can be repeated, producing formulas \(\lambda_i\) characterizing each layer, and thus it is possible to deal syntactically with a qualitative degree of beliefs (Grove 1988; Spohn 1988), looking for what holds ‘from some level up’ (see also Velázquez-Quesada 2017).