Subjective Use of Modals

Modal verbs — epistemic (subjective) use

In their epistemic/subjective use, modal verbs express the speaker's assessment of probability or certainty — not obligation or permission. This is a sophisticated register used to hedge statements or express degrees of certainty.

Epistemic modals in the present

Modal	Epistemic meaning	Probability	Example
müssen	must be / certainly	~90%	Er muss krank sein. (He must be ill.)
dürfen	may well / probably	~80%	Das dürfte stimmen. (That is probably correct.)
sollen	allegedly / reportedly	third-party info	Er soll sehr reich sein. (He is said to be very rich.)
wollen	claims to / allegedly	subject's own claim	Er will das gesehen haben. (He claims to have seen it.)
können	may / could be	~50%	Er kann krank sein. (He may be ill.)
mögen	may / might	concessive	Das mag sein. (That may be so.)

Past epistemic use (+ Infinitiv II)

For assumptions about the past, combine the modal with Infinitiv II (Partizip II + haben/sein):

Er muss krank gewesen sein. (He must have been ill.) / Sie kann das gemacht haben. (She may have done it.)

⚠️ Don't confuse objective and epistemic: Er muss arbeiten (deontic: he has to work) vs. Er muss arbeiten (epistemic, from context: he must be working). Context is essential for interpretation.