 A proposition can be defined as the basic semantic content of a sentence or in more philosophical terms what a sentence says about the world. One argument in favour of using such an abstraction is that different sentences may be converted into identical propositions. Here are some examples. These sentences have the same meaning. This meaning is defined in terms of so-called propositions. Propositions are labelled with small letters from P for proposition upwards. If you have one proposition only, it is always labelled P. If you have two propositions, you have P and Q. If you have three, P, Q and R, and so on. The following properties are usually ascribed to propositions. Propositions have a truth value, that is, they can be true, capital T or false, capital F. They may be known, believed, doubted, asserted, denied or queried and they remain constant when translated between languages. However, the truth value by and large depends on our world knowledge and the number of additional parameters. They include the general content. This proposition, for example, is true if the content is in line with our basic understanding of the world. The speaker who utters the sentence, this proposition may be true, but what if a blind speaker utters this sentence? The temporal and local context within which the sentence is uttered. This proposition is only true if the sentence is uttered during daytime. In summary, a proposition is a central concept in sentence semantics and it denotes a potential fact about the world which can be true or false.