Present Indicative of Possum

Possum, posse, potuī means “be able,” “can,” or, in some contexts, “may.” It is one of the most frequent Latin verbs and one of the first apparently irregular paradigms worth understanding rather than merely memorizing. Its present forms combine an old element pot- “able” with forms of sum “be,” so most of the surprises are regular sound adjustments at that boundary.

The forms on this page are present, indicative, and morphologically active. The present locates an ability or possibility in the current situation or presents it as generally true; the indicative asserts that situation as a fact. Possum has no ordinary passive paradigm, because “be able” does not describe an action transferred from an agent to a patient.

The present paradigm

The alternation is phonological. Before a form of sum beginning in s, pot- assimilates to pos-: pot-sum becomes possum, and the same logic gives possumus and possunt. Before vowel-initial es, est, and estis, the t remains: potes, potest, potestis. The present infinitive posse shows the same assimilation. This pattern is limited but real; it is not permission to invent forms such as potit or possetis in the present indicative.

How to parse before translating

When you meet one of these forms, do not begin with the English word “can.” First identify the Latin morphology. In potestis, -tis marks second-person plural, pot- identifies possum, and the absence of a tense marker such as imperfect -erā- or perfect-stem material points to the present system. The result is “you all are able.” Only then choose natural English: “you can,” “are you able,” or occasionally “you may” when the context grants permission.

The same discipline prevents a common mistake with possunt. Its -nt points to third-person plural, so its subject must be plural or understood as plural. Latin normally omits subject pronouns because the ending already supplies person and number.

Possum with an infinitive

Most often, possum is completed by a present infinitive that names the action within someone’s power. The finite form of possum carries person, number, tense, and mood; the infinitive does not. In scīre potest, “he can know,” potest is the finite verb and scīre supplies the action.

English also uses a bare infinitive after “can”: “can know,” not “can to know.” Latin uses the full infinitive form, recognizable here by -re. Do not add a preposition equivalent to English “to.”

The last example shows that possum can stand without an expressed infinitive when the action is recoverable from context. That is ordinary (neutral Classical prose), not an ellipsis peculiar to poetry.

Ability, circumstance, and possibility

English “can” covers several related ideas, and Latin possum does too. It may describe learned or physical capacity (Latīnē legere possum), practical opportunity (nunc venīre possum), or objective possibility (hoc fierī potest). Context determines whether the smoothest English translation is “can,” “be able,” or “be possible.”

The Latin tense label still does not dictate one mechanical English form. A present Latin statement may receive an English simple present (“she can”), a progressive paraphrase (“she is managing to”), or a future-oriented translation when an adverb supplies the time (“she can come tomorrow”). The Latin morphology asserts present ability; the wider sentence locates the intended event.

The same construction appears naturally in poetry (literary). The following attributed text is reproduced without pedagogical macrons:

Compare the minimal contrast:

Negation is straightforward: nōn normally stands before the finite verb. Unlike English “cannot,” Latin does not fuse the negative with possum.

Principal parts and the limits of prediction

Learn the lexical entry as possum, posse, potuī. The first principal part gives the first-person present and identifies the unusual present pattern. The infinitive confirms posse. The perfect potuī reveals the perfect stem potu-; it does not build the present forms. There is no regular fourth principal part because possum lacks an ordinary passive participial system.

This is an honest irregularity: the principal parts tell you which stems exist, but they do not make every surface form predictable without the six-form paradigm. Once the pos-/pot- alternation is learned, however, the present is a small, coherent system rather than six unrelated words. For the wider family of tenses, see Possum.

Common Mistakes

1. Regularizing the third-person singular. The form is built on pot- plus est, not on a guessed regular ending.

2. Translating English “can” as a separate uninflected word. Latin places person and number on possum itself.

3. Adding a preposition before the complementary infinitive. Latin uses the infinitive directly.

4. Making the infinitive agree with the subject. Only the finite verb marks the subject here.

Key Takeaways

The present paradigm is possum, potes, potest, possumus, potestis, possunt. Parse its ending first, then interpret its meaning. Use it directly with an infinitive, place nōn before it for negation, and remember that pos- before s but pot- before a vowel explains most of the apparent irregularity.