Epistemic modality involves an assessment of the reality of the proposition expressed. The default origo for this assessment is the speaker. However, this modality is also possible in questions, where the origo shifts to the hearer.

Epistemic modalities
term modal relation example
assumptive I assume p That should be true.
inferential I infer p That must be true.
speculative I guess that p That may well be true.
hypothetical I assume p conditionally That could be true.
potential I consider p possible That might be true.