In syntactic literature, adverbial clauses are often analyzed as maintaining a hierarchy regarding their contribution to the core proposition of a sentence. Specifically, some adverbial clauses contribute to the "at-issue" (or main) content, making them syntactically accessible to focus-marking mechanisms, polar interrogation, and direct negation, whereas others carry "not-at-issue" (presupposed) content and resist these operations. Regarding English syntax, I am looking to clarify the relationship between structural focus (clefting) and non-clifted constituent negation across different types of adverbial adjuncts (e.g., reason vs. purpose clauses). I have the following interrelated questions:
Hierarchy and Structural Focus: Does English exhibit a similar hierarchical stratification among adverbial clauses regarding their status as at-issue content?
The Equivalence of Clefting and Non-Clefted Negation: Is an adverbial clause’s eligibility for structural focus (it-clefting) strictly bi-conditional (equivalent) to its eligibility for contrastive constituent negation without focus-marking assistance (e.g., using the not X but Y / not because... but because... schema)?
Syntactic Implication and Universality of the Matrix: More broadly, does there exist a generalized, non-clefted contrastive negation framework in English such that: if an adverbial clause can be clefted, it is entailed that it can also undergo this specific type of direct constituent negation? Or do certain adverbial adjuncts break this symmetry by allowing one operation but rejecting the other?
Attention
①Please do not answer unless you have a solid background in generative syntax, information structure, and the syntax–semantics/pragmatics interface. I would appreciate answers based on the relevant linguistic literature rather than intuition or personal impressions.
②Please also keep the discussion focused on the linguistic questions themselves, and avoid commenting on unrelated aspects of the post or making general evaluations that are not directly supported by the relevant theoretical literature.