Infinitive means unconfined, or unlimited. This mood is called the infinitive, because its verb is not confined or limited to a nominative. A verb in any other mood is limited; that is, it must agree in number and person with its nominative; but a verb in this mood has no nominative, therefore, it never changes its termination, except to form the perfect tense. Now you understand why all verbs are called finite or limited, excepting those in the infinitive mood.
NOTE. To, the sign of the infinitive mood, is often understood before the verb; as, "Let me proceed;" that is, Let me to proceed. See RULE 25. To is not a preposition when joined to a verb in this mood; thus, to ride, to rule; but it should be parsed with the verb, and as a part of it.
If you study this lecture attentively, you will perceive, that when I say, I write, the verb is in the indicative mood; but when I say, if I write, or, unless I write, &c. the verb is in the subjunctive mood; write thou, or write ye or you, the imperative; I may write, I must write, I could write, &c. the potential; and to write, the infinitive. Any other verb (except the defective) may be employed in the same manner.
II. OF THE TENSES.
TENSE means time.
Verbs have six tenses, the Present, the Imperfect, the Perfect, the Pluperfect, and the First and Second Future tenses.
The PRESENT TENSE represents an action or event as taking place at the time in which it is mentioned; as, "I smile; I see; I am seen."
NOTE 1. The present tense is also used in speaking of actions continued, with occasional intermissions, to the present time; as, "He rides out every morning."
2. This tense is sometimes applied to represent the actions of persons long since dead; as, "Seneca reasons and moralizes well; An honest man is the noblest work of God."