Infinitives
The infinitive is a verbal noun that is not limited by a specific person or number (in-, “not”; -finitive, from finīre, “to put a limit or boundary on”). You’ve already seen many infinitives as part of verbal dictionary entries: remember that the second principal part is the present active infinitive, often translated with the preposition “to” and the verb’s meaning.
Infinitives do not have a person, number, or mood, but they do have tense and voice. There are six types of infinitives; you need only worry about the four discussed below for now. The two that we will learn about in the second semester are the future active infinitive and the future passive infinitive.
Present Active Infinitive
As stated above, you get the present active infinitive directly from the second principal part of the verb’s dictionary entry. For example, in the verb moneō, monēre, monuī, monitus, “to warn”, the present active infinitive is monēre, and it can be translated as “to warn.”
Present Passive Infinitive
The present passive infinitive is similarly translated with the preposition “to”, but the action of the verb is passive, rather than active. So, the passive form of the example above is “to be warned.”
To form the present passive infinitive in 1st, 2nd, and 4th conjugation verbs, you take the present active infinitive and replace the final -e with an -ī. So, for example:
- amāre, “to love” –> amārī, “to be loved”
- timēre, “to fear” –> timērī, “to be feared”
- audīre, “to hear” –> audīrī, “to be heard”
To form the present passive infinitive in the 3rd and 3rd -iō conjugations, you must replace the entire -ere ending of the present active infinitive with the -ī.
- regere, “to rule” –> regī, “to be ruled”
- capere, “to take” –> capī, “to be taken”
Perfect Active Infinitive
The perfect active infinitive, as the name suggests, indicates an action that occurred in the past. The English translation uses “to” and auxiliary verbs like “have” to get across the past-ness of the action: for example, “to have loved.”
To form the perfect active infinitive, you go to the perfect stem (which, as a reminder, is found by going to the third principal part of a dictionary entry and chopping off the -ī) and then add the ending -isse. This is the rule across all conjugations.
- amāvī, “I loved” –> amāvisse, “to have loved”
- timuī, “I feared” –> timuisse, “to have feared”
- rēxī, “I ruled” –> rēxisse, “to have ruled”
- cēpī, “I took” –> cēpisse, “to have taken”
- audīvī, “I heard” –> audīvisse, “to have heard”
Perfect Passive Infinitive
The perfect passive infinitive, as the name suggests, indicates a passive action that occurred in the past. The translation adds “been” to convey the passiveness of the verbal unit: for example, “to have been loved.”
The formation of the perfect passive infinitive works similarly to the formation of the perfect passive indicative. You take the fourth principal part of the dictionary entry (the perfect passive participle) in the appropriate gender, case, and number and pair it with the present infinitive of the verb “to be,” esse. Take a look at these examples:
- amātus esse, “to have been loved”
- monitus esse, “to have been warned”
- rectus esse, “to have been ruled”
- captus esse, “to have been taken”
- audītus esse, “to have been heard”
Note that in these examples, I used only the masculine nominative singular forms, but the perfect passive participle as part of the perfect passive infinitive can change its gender, case, and number to match the noun that it is properly describing. For example, if it were feminine nouns being heard, like vocēs, “voices”, then the proper form of the infinitive would be audītae esse.
We’ll learn more about how to use the perfect passive infinitive later on. It suffices for now to know how to form it and that it exists.
Uses of the Infinitive
There are various ways in which we can use the infinitive, a verbal noun, in Latin. We’ll discuss two now.
1. As a noun (subjective)
Because the infinitive is a verbal noun, it can stand as the subject of a sentence. When used in this way, the infinitive is a neuter nominative singular noun, and it most often shows up in linking sentence types or with impersonal verbs.
- errāre est humanum. “To err is human.” OR “It is human to err.”
Note that the predicate nominative adjective humanum is neuter nominative singular because it’s modifying errāre via the linking verb est.
The subjective infinitive, though used as a noun, still retains its verbal qualities in that it can be qualified by direct objects or prepositional phrases. Here are some examples:
- cēnam parāre est prudēns. “To prepare the dinner is wise.” OR “It is wise to prepare the dinner.”
- sedēre prō igne iūvat. “To sit in front of the fire is pleasing.” OR “It is pleasing to sit in front of the fire.”
2. Complementary
The infinitive can also be used to complete the meaning of a main verb. For example, with the verb possum, posse, potuī, “to be able to, can”, it would be odd to have simply a conjugated form of that verb without anything to complete its meaning:
- potest. “She can.” She can what?!
This is where the complementary infinitive can help; it completes the sense begun by a main verb. And like the subjective infinitive, it can take its own direct objects or prepositional phrases.
- canere potest. “She can sing.” OR “She is able to sing.”
- vidēre eōs poterāmus. “We were able to see them.”