22 ideas
18951 | For scientific purposes there is a precise concept of 'true-in-L', using set theory [Putnam] |
18953 | Modern notation frees us from Aristotle's restriction of only using two class-names in premises [Putnam] |
18949 | The universal syllogism is now expressed as the transitivity of subclasses [Putnam] |
18952 | '⊃' ('if...then') is used with the definition 'Px ⊃ Qx' is short for '¬(Px & ¬Qx)' [Putnam] |
18958 | In type theory, 'x ∈ y' is well defined only if x and y are of the appropriate type [Putnam] |
18954 | Before the late 19th century logic was trivialised by not dealing with relations [Putnam] |
18956 | Asserting first-order validity implicitly involves second-order reference to classes [Putnam] |
18962 | Unfashionably, I think logic has an empirical foundation [Putnam] |
18961 | We can identify functions with certain sets - or identify sets with certain functions [Putnam] |
18955 | Having a valid form doesn't ensure truth, as it may be meaningless [Putnam] |
14212 | A consistent theory just needs one model; isomorphic versions will do too, and large domains provide those [Lewis] |
18959 | Sets larger than the continuum should be studied in an 'if-then' spirit [Putnam] |
14213 | Anti-realists see the world as imaginary, or lacking joints, or beyond reference, or beyond truth [Lewis] |
18957 | Nominalism only makes sense if it is materialist [Putnam] |
18950 | Physics is full of non-physical entities, such as space-vectors [Putnam] |
14210 | A gerrymandered mereological sum can be a mess, but still have natural joints [Lewis] |
18960 | Most predictions are uninteresting, and are only sought in order to confirm a theory [Putnam] |
14215 | Causal theories of reference make errors in reference easy [Lewis] |
14209 | Descriptive theories remain part of the theory of reference (with seven mild modifications) [Lewis] |
21796 | Man is God if he raises himself, by denying his nature and finitude [Hegel] |
21783 | State slavery is a phase of education, moving towards a full culture [Hegel] |
21784 | Slavery is unjust, because humanity is essentially free [Hegel] |