An understanding of the syntactic and semantic properties of the two constructions illustrated in the sentences below has been an important achievement of generative grammar and has played a key role in the development of current syntactic theories.
a. It seems that the tire's flat.
b. The tire seems to be flat.
As is well known, in classical transformational grammar and its derivatives in which transformations are preserved in some form, (b)-type sentences are related, in part, to the corresponding (a)-type sentences by RAISING, a phenomenon whereby what is the subject of the embedded clause at an underlying level of representation becomes the subject of the main clause at a superficial level of representation. More precisely, in the principles and parameters framework, as developed in Chomsky (1981) and much subsequent work, it is assumed that such verbs have no external argument (or underlying subject) and subcategorize for either a tensed or infinitival clausal complement. When the complement is infinitival, its subject must move into the empty subject position of the main clause in order to be Case-marked, since there is no Case-assigning governor of the embedded subject position and all NPs must be assigned Case; the result is the construction in (b), in which a trace of the moved NP occupies the embedded subject position. When the complement is tensed, the embedded subject finds a Case-assigning governor within the complement itself (i.e., the agreement inflection); the result is the construction in (a), in which the underlyingly empty main clause subject position is filled by the expletive pronoun it.
This paper considers some different potential solutions to the problem posed by paraphrases of (a-b) such as The tire seems like it's flat, which looks like it has raising while at the same time having an overt pronoun in a Case-marked position in the complement clause.