36 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] |
| 18959 | Sets larger than the continuum should be studied in an 'if-then' spirit [Putnam] |
| 18957 | Nominalism only makes sense if it is materialist [Putnam] |
| 18950 | Physics is full of non-physical entities, such as space-vectors [Putnam] |
| 18960 | Most predictions are uninteresting, and are only sought in order to confirm a theory [Putnam] |
| 13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
| 21181 | Relativity and Quantum theory give very different accounts of forces [Hesketh] |
| 21183 | Thermodynamics introduced work and entropy, to understand steam engine efficiency [Hesketh] |
| 21199 | Spinning electric charge produces magnetism, so all fermions are magnets [Hesketh] |
| 21191 | Photons are B and W° bosons, linked by the Higgs mechanism [Hesketh] |
| 21189 | Electrons may have smaller components, bound by a new force [Hesketh] |
| 21180 | Electrons are fundamental and are not made of anything; they are properties without size [Hesketh] |
| 21182 | Quantum mechanics is our only theory, and is very precise, and repeatedly confirmed [Hesketh] |
| 21184 | Physics was rewritten to explain stable electron orbits [Hesketh] |
| 21187 | Virtual particles can't be measured, and can ignore the laws of physics [Hesketh] |
| 21185 | Colour charge is positive or negative, and also has red, green or blue direction [Hesketh] |
| 21194 | The Standard Model omits gravity, because there are no particles involved [Hesketh] |
| 21195 | In Supersymmetry the Standard Model simplifies at high energies [Hesketh] |
| 21197 | Standard Model forces are one- two- and three-dimensional [Hesketh] |
| 21188 | Quarks and leptons have a weak charge, for the weak force [Hesketh] |
| 21186 | Quarks rush wildly around in protons, restrained by the gluons [Hesketh] |
| 21192 | Neutrinos only interact with the weak force, but decays produce them in huge numbers [Hesketh] |
| 21196 | To combine the forces, they must all be the same strength at some point [Hesketh] |
| 21190 | 'Space' in physics just means location [Hesketh] |
| 20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
| 21193 | The universe is 68% dark energy, 27% dark matter, 5% regular matter [Hesketh] |
| 21198 | If a cosmic theory relies a great deal on fine-tuning basic values, it is probably wrong [Hesketh] |