Linguists also differentiate moods into two parental irrealis categories&colon; deontic mood and epistemic mood. A phenomenon can receive interpretation either ontic or epistemic. Is vagueness semantic, metaphysical or epistemic? Philosophy of science focuses on metaphysical, epistemic and semantic aspects of science. Naturalistic explanations for religious experiences are often seen as undermining their epistemic value. These include epistemic, metaphysical and ethical claims. Process reliabilism is a form of epistemic externalism. Virtue epistemologists differ in what they believe epistemic virtues to be. Some languages mark evidentiality separately from epistemic modality. Uncertainty quantification intends to work toward reducing epistemic uncertainties to aleatoric uncertainties. Some features of epistemic modal logic are in debate. Uncertainty refers to epistemic situations involving imperfect or unknown information. Western artists and philosophers used the Arab findings in new frameworks of epistemic relevance. Verbs are marked for voice, aspect, tense, and epistemic modality/evidentiality. These can be made precise using epistemic modal logic; see for details.