1988, Andrew Radford, chapter 6, inTransformational grammar: a first course, Cambridge, UK: Cambridge University Press, page306:
Although a finite I ( = INFL =INFLECTION) constituent is (overtly or covertly) inflected forTENSE orAGREEMENT properties, it should be obvious that anonfinite I in English lacks these properties. Hence, the infinitival particleto which occurs in anonfinite I is by its very naturetenseless andagreementless (i.e. it carries no Tense or Agreement properties, and is thus an entirely uninflected form). The difference between afinite and anonfinite Clause can thus be seen to lie in the nature of I: a finite Clause is one which contains a finite I (carrying Tense and Agreement properties); anonfinite Clause is one which contains anonfinite I which is tenseless and agreementless.
