A sentence is an image of reality: it shows its sense.

A sentence is both an image and a model of what we think reality is. At first sight, the (printed) sentence does not seem to be an image of the reality it treats. But neither do written notes seem at first sight to be an image of a piece of music, nor our phonetic notation (the alphabet) to be an image of our speech. And yet these sign languages prove to be images, even in the ordinary sense, of what they represent.

Obviously, we perceive the proposition (aRb) as an image. In this case the sign is a likeness of what it denotes. And if we penetrate to the essence of this representation, we see that it is not impaired by seeming irregularities (such as the use of ♯ and ♭in musical notation). For these exceptions also depict what they are meant to express; only in another way. A gramophone record, the musical idea, the written notes, and the sound-waves, all relate to one another in the same internal relation that holds between language and the world. They are all constructed according to a common logical pattern.

There is a general rule by means of which the musician can obtain the symphony from the score, and which makes it possible to derive the symphony from the groove on the gramophone record, and, using the first rule, to derive the score again. It constitutes the inner similarity between such entirely different constructs. And that rule is the law of projection which projects the symphony into the language of musical notation. It is the rule for translating this language into the language of gramophone records.

The possibility of all imagery, of all vividness of expression, is contained in the logic of depiction. In order to understand the nature of a sentence, consider hieroglyphic script, which depicts the facts that it describes. Alphabetic script developed from it without losing what was essential to depiction. We can see this from the fact that we understand the sense of a propositional sign without its having been explained to us.

A sentence is an image of reality: for if I understand a sentence, I know the situation that it represents and I understand it without having had its sense explained to me. It shows its sense, it shows how things stand if it is true; and it says that they do so stand.