what is it?
German modal verbs have two distinct uses. In their objective use they express obligation, permission, or ability (e.g. Du musst das tun — «You must do that»). In their subjective (epistemic) use they express the speaker's assessment of how likely something is, or they report what someone else claims. The modal itself carries the speaker's judgment — certainty, probability, possibility, hearsay, or an unverified personal claim — while the main verb appears as an infinitive. This page covers only the epistemic use.
when to use it
Choose the modal that matches the degree of certainty or the source of the information:
muss — near-certain deduction. The speaker has strong evidence and concludes something must be the case. Equivalent to «it must be / it has to be».
dürfte — high probability, slightly hedged. The speaker considers something very likely but not certain. Equivalent to «it should be / it is probably».
könnte / kann — open possibility. The speaker acknowledges something is conceivable. Equivalent to «it could be / it may be». Könnte (Konjunktiv II) is more tentative than kann.
soll — hearsay. The speaker is reporting what a third party says or what is generally reported. The speaker does not vouch for the truth. Equivalent to «reportedly / it is said that».
will — unverified self-claim. The subject of the sentence claims something about themselves, but the speaker is sceptical or neutral. Equivalent to «claims to / maintains that».
formation
The structure is straightforward: the modal verb is conjugated and occupies the finite verb position (V2 in main clauses), and the main verb follows as a bare infinitive at the end of the clause.
Present reference: subject + modal (finite) + … + infinitive
Past reference: subject + modal (finite) + … + Partizip II + haben/sein (Infinitiv). This is called the perfect infinitive and is the only way to refer to a past state of affairs with an epistemic modal.
| modal | epistemic meaning | present-reference example | past-reference example |
|---|---|---|---|
| muss | near-certain deduction | Er muss krank sein. | Er muss krank gewesen sein. |
| dürfte | high probability | Das dürfte stimmen. | Das dürfte ein Fehler gewesen sein. |
| könnte | open possibility | Sie könnte Recht haben. | Sie könnte es vergessen haben. |
| soll | hearsay (third-party) | Das Restaurant soll gut sein. | Er soll früher hier gewohnt haben. |
| will | unverified self-claim | Er will alles wissen. | Der Zeuge will nichts gesehen haben. |
Note that dürfte is already Konjunktiv II of dürfen. It has no separate Konjunktiv II form for epistemic use — dürfte is the form you use.
examples in context
common pitfalls
Using a past-tense modal instead of modal + perfect infinitive for past deductions.
To express a deduction about a past event, keep the modal in the present tense and use the perfect infinitive for the main verb. Do not put the modal itself in the past tense.
Incorrect: «Er musste krank sein.» — this reads as an objective obligation in the past («He was required to be ill»), not a deduction.
Correct: «Er muss krank gewesen sein.» — present-tense modal + perfect infinitive = past deduction.
Confusing epistemic soll with obligation soll, and epistemic will with future/intent will.
Context is the key. When soll refers to what a third party reports about the subject (not what the speaker orders), it is epistemic hearsay: «Das Restaurant soll gut sein» (people say it is good) vs. «Du sollst das tun» (you are supposed to do that — obligation). When will has a third-person subject and describes what that person claims about themselves, it is an unverified self-claim: «Er will alles gesehen haben» (he claims to have seen everything) vs. «Ich will das machen» (I want to / intend to do that).
Reading epistemic dürfte as permission.
In its objective use, darf means «is allowed to». But dürfte (Konjunktiv II) in an epistemic context expresses probability, not permission. «Das dürfte stimmen» does not mean «that is allowed to be correct» — it means «that is probably correct». When you see dürfte with a statement about the world rather than a rule or authority, interpret it as a probability marker.