- Fregean senses(philosophy of language/logic)
- A concept from philosopher Gottlob Frege: the meaning or way of understanding something (like how 'the morning star' and 'the evening star' have different senses even though they refer to the same planet, Venus).
- Gottlob Frege(historical philosopher)
- A late 19th and early 20th-century German philosopher and logician who made fundamental contributions to understanding how language and meaning work.
- Hesperus is Phosphorus(the primary example used)
- A famous example in philosophy: Hesperus and Phosphorus are both ancient names for Venus (the planet), and the statement points out that discovering they're the same planet tells us something deep about how names and necessity work.
- Necessary(ontological distinction in Mulla Sadra's metaphysics)
- The principle, God; pure existence without essence, quality or property that undergoes change or motion
- a posteriori(Used to classify the epistemic status of necessary statements post-Kripke)
- Knowable, but not independently of empirical experience
- epistemic necessity(Distinguished from other kinds of necessity in formal epistemology)
- The necessity of things that must be true given what one knows.
- explicable(as used in describing what a theory can or cannot explain)
- Able to be explained or accounted for by a theory or reason.
- identity statements(as used in logic and metaphysics)
- Sentences that claim two things are the same, like 'water is H2O' or 'the morning star is the evening star.'
- metaphysical necessity(Distinguishing types of necessity)
- A property of things that must be the case but not purely by logical form — true in all possible worlds without being logical tautologies