25 ideas
17641 | Discoveries in mathematics can challenge philosophy, and offer it a new foundation [Russell] |
17638 | If one proposition is deduced from another, they are more certain together than alone [Russell] |
17632 | Non-contradiction was learned from instances, and then found to be indubitable [Russell] |
18767 | Free logics has terms that do not designate real things, and even empty domains [Anderson,CA] |
18763 | Basic variables in second-order logic are taken to range over subsets of the individuals [Anderson,CA] |
18771 | Stop calling ∃ the 'existential' quantifier, read it as 'there is...', and range over all entities [Anderson,CA] |
17629 | Which premises are ultimate varies with context [Russell] |
17630 | The sources of a proof are the reasons why we believe its conclusion [Russell] |
17640 | Finding the axioms may be the only route to some new results [Russell] |
17627 | It seems absurd to prove 2+2=4, where the conclusion is more certain than premises [Russell] |
17628 | Arithmetic was probably inferred from relationships between physical objects [Russell] |
18769 | Do mathematicians use 'existence' differently when they say some entity exists? [Anderson,CA] |
18770 | We can distinguish 'ontological' from 'existential' commitment, for different kinds of being [Anderson,CA] |
18766 | 's is non-existent' cannot be said if 's' does not designate [Anderson,CA] |
18768 | We cannot pick out a thing and deny its existence, but we can say a concept doesn't correspond [Anderson,CA] |
18765 | Individuation was a problem for medievals, then Leibniz, then Frege, then Wittgenstein (somewhat) [Anderson,CA] |
18764 | The notion of 'property' is unclear for a logical version of the Identity of Indiscernibles [Anderson,CA] |
13768 | Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington] |
13770 | There are many different conditional mental states, and different conditional speech acts [Edgington] |
13764 | Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington] |
13765 | 'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington] |
17637 | The most obvious beliefs are not infallible, as other obvious beliefs may conflict [Russell] |
17639 | Believing a whole science is more than believing each of its propositions [Russell] |
17631 | Induction is inferring premises from consequences [Russell] |
17633 | The law of gravity has many consequences beyond its grounding observations [Russell] |