The Development of the Cyclic Principle
Since the mid-1960s, the cyclic principle, in one form or another, has played an important role in syntactic theorizing. The core concept has remained relatively stable, but there have been a variety of technical implementations, and one substantial augmentation, ‘‘successive cyclicity,’’ introduced in the early 1970s and figuring prominently in ‘‘On Wh Movement’’ (Chomsky 1977). It will be my modest purpose here to survey some of these developments, exploring their motivations and consequences.
The cyclic principle, along with analysis into distinctive features, was one of two major syntactic innovations of the mid-1960s borrowed from phonology. The principle was first formulated in Chomsky, Halle, and Luko¤ 1956, and applied in the phonological analysis of a variety of languages from the early 1960s on. Chomsky and Halle 1968, the monumental examination of the phonology of English, made crucial use of the cycle in virtually every analysis. The fundamental idea is that complex words have nested internal structure and that (certain) phonological rules apply first to the most deeply embedded constituent, then to the next most deeply embedded, and so on. In (1), for example, first the Word Stress Rule applies to the individual components black, board, and eraser, assigning each a primary stress indicated by ‘‘1’’; then the Compound Stress Rule, which reassigns primary stress to the leftmost primary stress in its domain, applies to black board; and finally it applies to black board eraser. Each reassignment of primary stress weakens all nonprimary stresses in the domain by one degree.


In this case, and in a vast number of others, such cyclic application correctly accounts for the facts. Chomsky and Halle sum up the situation as follows: ‘‘it is natural to suppose that in general the phonetic shape of a complex unit...will be determined by the inherent properties of its parts and the manner in which these parts are combined, and that similar rules will apply to units of different levels of complexity. These observations suggest a general principle for the application of rules of the phonological component, namely, what we shall call the principle of the ‘transformational cycle’’’ (1968, 15).
In Aspects of the Theory of Syntax (1965), Chomsky introduced the cyclic principle into syntactic theory as part of a revised organization of the grammar. In the original Chomskyan framework, outlined in ‘‘The Logical Structure of Linguistic Theory’’ (LSLT; Chomsky 1955), the phrase structure rules produced only simple monoclausal structures, which could then be merged by generalized transformations conjoining two (or more) separate structures, or embedding one into another. In that framework, the generalized transformations constituted the recursive component of the grammar. The Aspects alternative was that the phrase structure rule com ponent itself had a recursive character. Chomsky’s major arguments for this new organization were that it resulted in a simpler overall theory, and at the same time it explained the absence of certain kinds of derivations that seemed not to be needed. The second of these points is our concern here.
As just discussed, the LSLT model had generalized transformations to combine a ‘‘forest of trees’’ into a single tree. It also had singulary transformations (Passive, Subject-Auxiliary Inversion, etc.), which operated on single trees, whether basic ones or ones produced by the operation of generalized transformations. Following Fillmore (1963), Chomsky argued that while there is extensive ordering among singulary transformations (situations where a derivation produces an unacceptable sentence if two transformations are applied in reverse order), ‘‘there are no known cases of ordering among generalized embedding transformations although such ordering is permitted by the theory of Transformation-markers’’ (1965, 133). One classic example of strict ordering between singulary transformations centers on passive sentences, which, in the classical model, had active underlying forms. Consider, in this light, the following pair, which arise from the same underlying form:

The Number Agreement transformation is crucially ordered after the Passive transformation. The reverse order of application would give (4) instead of the desired (3).

Further, Chomsky claimed that while there are many cases of singulary transformations that must apply to a constituent sentence before it is embedded, or that must apply to a ‘‘matrix’’ sentence after another sentence is embedded in it, ‘‘there are no really convincing cases of singulary transformations that must apply to a matrix sentence before a sentence transform is embedded in it’’ (1965, 133).
In the Aspects theory, as in the LSLT theory, there was extensive ordering among singulary transformations. In both frameworks, the set of singulary transformations was seen as a linear sequence: an ordered list. Given the Aspects modification, this list of rules applied cyclically, operating first on the most deeply embedded clause, then on the next most deeply embedded, and so on, working up the tree until the rules applied on the highest clause, the entire generalized phrase marker. Thus, singulary transformations applied to constituent sentences ‘‘before’’ they were embedded, and to matrix sentences ‘‘after’’ embedding had taken place. ‘‘The ordering possibilities that [were] permitted by the theory of Transformation-markers but apparently never put to use [were] now excluded in principle’’ (Chomsky 1965, 135).
Curiously, it was almost three decades before it became clear that this was not, as Chomsky presented it, a real argument against generalized transformations. For it was not recursion in the base that excluded the unwanted derivations: it was an implicit version of the cyclic principle. And three decades later, a version of the cyclic principle was to be grafted onto a theory with generalized transformations. The part of the cyclic principle that was actually articulated in Aspects was the Insertion Prohibition.

As noted by Chomsky (1973, 243), ‘‘The Insertion Prohibition...is a step toward a stricter interpretation of the cycle: it asserts that once a stage of the cycle has been passed, we cannot introduce material into it from the outside.’’ Observe, though, that (5) did not exclude all of the unwanted derivations. Even with this constraint, it was still possible to manipulate the contents of an embedded structure even after its cycle had been completed. There was a further implicit requirement, finally made explicit in Chomsky 1973, where Chomsky observed that (6) sharpened the notion of the cycle.

Later, Chomsky (1977, 73) asserted that ‘‘transformational rules, e.g., [Move NP and Move wh-phrase], meet the condition of the (strict) cycle.’’