We present the logic \({\mathsf {LCB}}\) which is expressed in a propositional language constantly enriched by new atomic expressions. Our formal framework is the propositional doxastic logic \({\mathsf {KD45}}\) with the belief operator \({\mathcal {B}}\), extended by the \({\mathcal {C}}\) operator, to be read it changes that ... . We describe the changing beliefs of an agent who uses progressively expanding language. The approach presented here allows us to weaken pragmatic objections to the so-called principle of negative retrospection accepted in \({\mathsf {KD45}}\) and the problem of logical omniscience. In what follows, we present the expanding propositional language used in our formalism, interpreted using an epistemic version of Kripke semantics. Next, we give a syntactic characterization of logic \({\mathsf {LCB}}\) and prove the soundness and completeness of \({\mathsf {LCB}}\) in respect to our semantics. Finally, we compare the idea of expanding language with the notion of agent awareness and we relate our formalism to two epistemic temporal logics.

我们介绍逻辑\（{\ mathsf {LCB}} \），该逻辑以命题语言表示，该命题语言不断被新的原子表达式所丰富。我们的正式框架是命题doxastic逻辑\（{\ mathsf {KD45}} \）的信念操作者\（{\ mathcal {B}} \） ，由扩展\（{\ mathcal {C}} \）算子，要读它改变了......。我们描述了使用逐渐扩展的语言的代理人不断变化的信念。这里介绍的方法使我们能够减弱对\（{\ mathsf {KD45}} \）中接受的所谓否定追溯原则和逻辑全能问题的实用反对。。接下来，我们介绍形式主义中使用的扩展命题语言，并使用认知形式的Kripke语义对其进行解释。接下来，我们给出的逻辑句法特征\（{\ {mathsf LCB}} \），并证明了可靠性和完整性\（{\ {mathsf LCB}} \）中对于我们的语义。最后，我们将语言扩展的概念与主体意识的概念进行了比较，并将形式主义与两种认知时间逻辑联系起来。