Barbara Partee gave her first lecture today (which was very interesting btw) and discussed three versions of the autonomy of syntax thesis (AoS) that I would like to quickly comment on here. Non- generativists regularly advert to the AoS citing it as one of Generative Grammar’s more obvious absurdities (e.g. see here). The thesis is interpreted as asserting that syntax is independent of meaning, understanding this to assert that the syntax of some expression has no consequences on what it means and vice versa. This view is rightly taken to be absurd. Fortunately, nobody has ever held this position. So what then is the AoS?
Barbara identified three different interpretations:
First, a negative thesis: syntax is not reducible to operations of the interface systems. This means that syntactic structures, syntactic rules and syntactic primitives are not reducible to semantic structures, rules and primitives (nor for that matter phonological ones, though few have been tempted with this kind of reduction). Of course, the converse is also true; the properties of the interpretive systems (meaning and “sound”) are not reducible to properties of the syntax. There are systematic interconnections, but no reduction. The classic illustration of this comes from thinking about the sentence “colorless green ideas sleep furiously” and comparing it to “green sleep colorless furiously ideas.” As observed long ago, neither sentence is particularly meaningful but the first is syntactically regular (viz. conforms to a standard English pattern as in “clear limpid prose persuades easily”), hence its greater acceptability when compared to the word salad of the second example despite the semantic anemia of both. The same point can be made by considering unacceptable sentences like “The girl seems sleeping.” This sentence has a perfectly clear meaning (viz. “the girl seems to be sleeping” and not “the girl seems sleepy”) even though the sentence is syntactically odd. To speak somewhat inexactly, ‘meaningful’ and ‘grammatical’ dissociate and hence there can be no reduction of one to the other.
The second interpretation of the AoS is more theory internal: it asserts that the application of syntactic operations is not conditional on semantic factors. Here is a useful formulation stolen form a handout of Fritz Newmeyer.
The syntactic rules and principles of a language are formulated without reference to meaning, discourse, or language use
This is stronger than the first version of the AoS for even if syntactic operations are semantically irreducible, the syntactic generation of a sentence could (logically) depend on the interpretation that the generated sentence has or the context in which it is used or the communicative intent of the speaker. Generative theories have generally respected this version of the AoS as well, though there have been suggested principles that violate it (at least in spirit). The Fox-Reinhart thesis is a contemporary example. It sanctions movement just in case the movement has an effect on meaning (Chomsky’s version adds a strong feature to the derivation just in case it has an effect on interpretation). Both appear to violate this second version of the AoS.
Just a caveat before moving on: the AoS should not be confused with the syntax first thesis mentioned in the psycho-ling literature. The latter is taken to be a principle of parsing which states that an expression must be assigned a complete syntactic structure before it is semantically evaluated. The AoS commits no hostages to the temporal dynamics involved in parsing. Parsing could interleave syntactic and semantic rules without the latter conditioning the former.
Barbara dubs the third interpretation explanatory autonomy. It is a methodological principle regulating what counts as a valid motivation for a syntactic proposal. Barbara interprets this to mean that semantic “facts” cannot justify postulating syntactic structure, only syntactic “facts” can. I find this version of the AoS problematic and am unsure if it ever had much of a hold on syntactic practice, though if it did it shouldn’t have. First, it is not clear that facts come labeled ‘syntactic’ and ‘semantic,’ and if not the regulative proposal is contentless (I believe that Chomsky once made a similar point but damn if I can recall where). Second, the intuitive version of this interpretation of the AoS has been regularly violated in practice from the earliest days of generative grammar. For example, what we now call thematic considerations have regularly been invoked in postulating common underlying structures for sentences related by movement, e.g. one good reason for thinking that actives (John kissed Mary) and passives (Mary was kissed (by John)) derive from a common underling structure is it allows the structural configurations of theta role assignment to be streamlined (e.g. in both cases ‘Mary’ is the underlying object). Indeed, this is so for all cases of movement.
Perhaps this version of the AoS had greater purchase in the Aspects era when the Katz-Postal hypothesis (KPH) was widely adopted. In KPH theories the only input to semantic interpretation is Deep Structure. If correct, transformations have to be meaning preserving as their outputs, Surface Structures, do not feed semantic interpretation. In such a context semantic concerns cannot motivate a particular transformation. If one identifies “transformational” with “syntactic” (a mistake, as Deep Structure is also a syntactic level in an Aspects style theory) the avoidance of “semantic” considerations would make sense. However, to repeat, there is no principled way of distinguishing a syntactic form a semantic fact and so the methodological dictum is hollow.
Let me end with one more quick distinction: The AoS should also be distinguished from another important claim, which I will dub the Primacy of Syntax thesis (PoSt). PoSt is a substantive claim asserting that syntax is where generativity lives. More specifically syntax is the recursive engine in natural language, the interfaces being “interpretive” rather than generative. No generative syntax, no complex thoughts, no unbounded structures. The syntax generates the structures that the semantics (and phonology) interprets. But, the semantics and phonology as such have no generative powers. If PoSt holds true then the first interpretation of the AoS follows. This said, the theses are different and are usefully distinguished.
 This is speaking inexactly for ‘grammatical’ contrasts with ‘meaningful’ in being a technical term. The predicate for observables is ‘acceptable.’ What the AoS examples above observe is that a notion of syntactic well-formedness is required in addition to meaningfulness if relative acceptability is to be accounted for.