A paper by Donald Davidson titled for truth and this concept uses the sentence (*) "Theaetetus flies" to show how a regress is avoided by using Tarskian T-sentences. One paper argues Odysseus possesses this concept but does not possess a related concept known as "Bedeutung". This concept distinguishes the sentences "Hesperus is Hesperus" and "Hesperus is Phosphorus" according to a paper titled for it and reference by Gottlob Frege. Semantic externalism was introduced in two papers titled for this concept that consider two versions of Oscar who respectively use “XYZ” and “H2O” to refer to water. Hilary Putnam used the Twin Earth thought experiment to argue that this concept “just ain't in the head”. For 10 points, semantics studies what concept, the information conveyed by a word (15[1])or phrase? ■END■