Infinitives

Table of contents

1. Infinitives
   1. Present Active Infinitive
   2. Present Passive Infinitive
   3. Perfect Active Infinitive
   4. Perfect Passive Infinitive
2. Uses of the Infinitive
   1. Subjective Infinitive
   2. Complementary Infinitive
      1. posse

---

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”). Often, the infinitive can be translated using the preposition “to”, as in “to love” or “to hear”. 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:

• present active
• present passive
• perfect active
• perfect passive
• future active
• future passive

You need only worry about the four discussed below for now; the future active and passive infinitives are used in very specific contexts that are not worth exploring at this early stage.

---

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” – we use the helping verb “be” and the past participle (or “-ed” form) of the verb.

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”, the helping verb “have”, and the past participle (or “-ed” form) of the verb 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 active 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 an 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 matrēs, “mothers”, then the proper form of the infinitive would be audītae esse. We’ll explore examples of this below and in the unit on indirect statements.

---

Uses of the Infinitive

The infinitive is a verbal noun, which means that it has characteristics of both parts of speech. The noun part means that it denotes the idea of an action and, when used in certain circumstances, can be considered to have a gender, case, and number (without needing to decline it). The verbal part means that the infinitive, like conjugated verbs, can take complements like direct objects, ablatives of agent, and so on.

There are various ways in which we can use the infinitive in Latin. We’ll discuss two now.

Subjective Infinitive

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 singular noun; it does not belong to any declension and we do not need any special endings on the infinitive to indicate these aspects.

It most often shows up in linking sentence types or with impersonal verbs. For example:

• errāre est humānum. “To err is human.” OR “It is human to err.”

Note that the predicate nominative adjective humānum 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.”

Complementary Infinitive

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” [more on this verb below], it would be odd to have simply a conjugated form of that verb without anything to complete its meaning:

• potest. “She can.” She can do what?!

Similarly, a verb like debeō, debēre, debuī, debitus, “to ought to”, “to be obligated to”, “should”, will expect some kind of action word to finish its meaning:

• equus debet. “The horse should.” The horse should what?!

This is where the complementary infinitive can help; it completes the sense begun by a main verb that expects an action to fill out its meaning. In this way, it functions more like an object on the other side of a conjugated verb, rather than a subject. 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.”
• nautae vidēre eum poterant. “The sailors were able to see him.”
• equus debet ab agricolā ductus esse. “The horse ought to have been led by the farmer.” or “The horse should have been led by the farmer.”

In this last example, note how the participle in the perfect passive infinitive (ductus) is masculine nominative singular because it is the horse (equus) that should have been led. If we had a different subject of a different gender and number, we would need to make sure that the participle matches appropriately. For example:

• animālia debent ab agricolā ducta esse. “The animals ought to have been led by the farmer.” (neuter plural for ducta because of the neuter plural subject animālia.

posse

The verb used in the examples above (possum, posse, potuī, – - to be able to, can) is an irregular verb in the present system, now the second such verb in our arsenal (the first being sum, esse, fuī, futūrus - to be). The verbs are related morphologically: note that most of the conjugated forms of posse in the present system (present tense, imperfect tense, and future tense) are basically the forms of the verb esse with either pos- or pot- prefixed in front (pos- before forms of esse that begin with an s and pot- before forms of esse that begin with a vowel). For comparison’s sake, here is the paradigm chart for esse in the three present system tenses followed by the paradigm chart for posse in the three present system tenses.

---