I am a little bit surprised by the principle of composionality in semantics (I'm very new to all of this), which states that the meaning of a complex expression is determined by the meanings of its constituent expressions and the rules used to combine them. When reading stuff like Categorial or Montangue Grammar or Davidson´s account of meaning based on truth values, this principle is a pillar of how meaning is constructed. The problem is that I do not understand why this is not trivially false. I am not thinking of the usual "exceptions" (sarcasm, literary language,...), but about very ordinary not-sarcastic expressions like:
I already had dinner
I've already read that book
Any competent speaker understand that the first "already" means some hours ago, while the second one can mean "earlier in my life". To know this, seems to me, one needs a detailed knowledge of human habits. An alien who just learned english as a formal system would not be able to adscribe truth-values of any sort to these sentences. Similarly, in
I have some of Marie's book at home
I have some of Jane Austen´s books at home,
the meaning of the genitive is that of ownership in one case and one of authorship in another. It seems obvious then that the notion of compositionality collapses and it is impossible to assign truth-values to utterances unless we take into account a notion of context that goes widely beyond the usual [speaker, time, place], including common beliefs, cultural items, etc. True, if you consider sentences like "John is running" or "Marie saw that John bought the car that Lucy painted" (which is what you find analysed with painstaking formal detail in books like Gamut's Logic, Language and Meaning), then compositionality seems to work, but these are artificial examples which do not represent ordinary language. Actually, by studying the metaphoric maps common in everyday language (I´m thinking of the contemporary theory of metaphor started by Lakoff in the 80´s), it is easy to derive dozens of common expressions that defy compositionaly in similar ways.
Is it not the case then that semantics does not make sense isolated, without pragmatics? I do not understand that there can really be something "in between" syntax and pragmatics that makes sense on its own.