Sentences and Propositions

At this point, clarity on the nature of both sentences and propositions is required. One cannot speak with clarity on matters of belief (direct or otherwise) while the concepts used to explain it are vague!

The first thing to become aware of is the nature of signs. I am using this word generally to refer to any mark, image, sound or other feature perceived through the senses that represents something. So traffic lights, pictures and words are all signs. Morse code, binary digits, bumps on a CD, and smoke signals are also signs. Signs may represent another sensory feature. This occurs in the case of pictures and recordings of various kinds. Signs may also represent a command: street signs and lights. They may also represent ideas. It is these last kind of signs that we are interested in, for they are the ones that are also known as sentences.

Sentences may be in any language, may be in any medium, and may be written, spoken, demonstrated (sign language) and so on. The unifying feature of sentences is that they express thoughts or ideas. But not every idea is one that can be either true or false. Some sentences are questions, others are commands and still others are declarative sentences. Those sentences that can meaningfully be called either true or false are the bearers of propositions.

A propositions is any thought that can meaningfully be called either true or false. Many sentences may express the same proposition. For example "Snow is white" and "La neige est blanche" (French) both express the proposition that snow is white.

These points apply to belief in a very simple way. One believes propositions, and only propositions. One cannot believe sentences, nor can one believe signs in general. These is because the object of belief is a thought, and belief comes down to whether the thought is thought to be either true or false.