 At this point, many issues become relevant to further discussions of logical form. Most obviously, there are questions concerning particular examples. Given just about any sentence of natural language, one can ask interesting questions (that remain unsettled) about its logical form. There are also very abstract questions about the relation of semantics to logic. Should we follow Davidson and Montague, among others, in characterizing theories of meaning for natural languages as theories of truth (that perhaps satisfy certain conditions on learnability)? Is an algorithm that correctly associates sentences with truth-conditions (relative to contexts) necessary and/or sufficient for being an adequate theory of meaning? What should we say about the paradoxes apparently engendered by sentences like ‘This sentence is false’? If we allow for second-order logical forms, how should we understand second-order quantification, given Russell’s Paradox? Are claims about the “semantic structure” of a sentence fundamentally descriptive claims about speakers (or their communities, or their languages)? Or is there an important sense in which claims about semantic structure are normative claims about how we should use language? Are facts about the acquisition of language germane to hypotheses about logical form? And of course, the history of the subject reveals that the answers to the central questions are by no means obvious: what is logical structure, what is grammatical structure, and how are they related? Or put another way, what kinds of structures do propositions and sentences exhibit, and how do thinkers/speakers relate them?