Hey I'm a philosophy major who really wants to advance my knowledge in philosophy. I love that you have a channel dedicated to philosophy, I liked this video a lot and will certainly watch more. Subscribed and liked :)
Hi Mark! Thanks for the video! At 7:45, you mentioned a logic system with KTB; In the context of doxastic logic, would that describe a reasoner who never believes any false proposition (T) and also believes that their beliefs are never inaccurate (B)?
Yes, KTB would describe someone whose beliefs are always true (so, more usually applied to knowledge) and, for any truth p, always believes they don't believe ~p. Or, to put it another way, for any falsehood, they believe they don't believe it. T is implausible for belief but plausible for knowledge. But B (p -> K~K~p) is implausible for knowledge: it implies, for any falsehood, you know you don't know it. How could the mere fact that something is false give you positive knowledge? Interestingly, B is linked to the other 'introspection' principles: 4, or 'positive introspection' (Kp -> KKP) and 5, 'negative introspection (~Kp -> K~Kp). Given B, 4 and 5 are equivalent. Some have argued that 4 but not 5 is plausible for knowledge.
Hi Mark, thanks for the video! I knew that the D in axiom D stands for "deontic", if this is true then we have two axioms whose names make sense ;) But I don't know whether D really stands for that...
Yeah I think D is for Deontic. D ensures no contradictions are necessary: it's equivalent to []T. In alethic logic, it ensures necessity implies possibility. In deontic logic, it means obligations imply permissions. Other axiom names: B is for Brouwer, the Dutch intuitionist logician. 4 and 5 come from CI Lewis's system numbering (systems 1-5), hence the logic names S4 and S5. Still a pain to remember!
Hey I'm a philosophy major who really wants to advance my knowledge in philosophy. I love that you have a channel dedicated to philosophy, I liked this video a lot and will certainly watch more. Subscribed and liked :)
Thanks! Glad it helped.
If only my professor could explain this clearly... Your videos make modal logic accessible and not as overwhelming :)
Aw thanks! Glad it helped.
Hi Mark! Thanks for the video! At 7:45, you mentioned a logic system with KTB; In the context of doxastic logic, would that describe a reasoner who never believes any false proposition (T) and also believes that their beliefs are never inaccurate (B)?
Also, does KB describe the doxastic logic for a reasoner who believes that their beliefs are never inaccurate (B)?
Yes, KTB would describe someone whose beliefs are always true (so, more usually applied to knowledge) and, for any truth p, always believes they don't believe ~p. Or, to put it another way, for any falsehood, they believe they don't believe it. T is implausible for belief but plausible for knowledge. But B (p -> K~K~p) is implausible for knowledge: it implies, for any falsehood, you know you don't know it. How could the mere fact that something is false give you positive knowledge? Interestingly, B is linked to the other 'introspection' principles: 4, or 'positive introspection' (Kp -> KKP) and 5, 'negative introspection (~Kp -> K~Kp). Given B, 4 and 5 are equivalent. Some have argued that 4 but not 5 is plausible for knowledge.
Hi Mark, thanks for the video! I knew that the D in axiom D stands for "deontic", if this is true then we have two axioms whose names make sense ;) But I don't know whether D really stands for that...
Yeah I think D is for Deontic. D ensures no contradictions are necessary: it's equivalent to []T. In alethic logic, it ensures necessity implies possibility. In deontic logic, it means obligations imply permissions.
Other axiom names: B is for Brouwer, the Dutch intuitionist logician. 4 and 5 come from CI Lewis's system numbering (systems 1-5), hence the logic names S4 and S5. Still a pain to remember!