To-infinitives in modern English represent a futuristic, indirect potential event while bare infinitives represent a direct one with the subject-predicate relationship in the construction of ‘verb+object+bare infinitives.’ This comes from the development process of grammatical properties of infinitives from OE to ME; to-infinitives and bare infinitives all had syntactic properties of verbal nouns. Generative linguists have long insisted that this results from structural properties; the to-infinitive has the clausal IP or CP with the inflectional element inside, while the bare infinitive has the small clause structure such as VP, as a meaningless functional category. In this paper, however, it is shown that, based on cognitive grammar, bare infinitive has a direct meaning relation of ‘subject-predicate’ with ‘object’ in the construction of ‘verb+object+bare infinitive,’ while to-infinitive has an indirect meaning relation in the construction of ‘verb+object+to-infinitive’ because of to. In short, the meaning difference between to-infinitives and bare infinitives in modern English comes from the morpheme to.