22 ideas
13838 | A decent modern definition should always imply a semantics [Hacking] |
13833 | 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking] |
13834 | Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking] |
13835 | Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking] |
13845 | The various logics are abstractions made from terms like 'if...then' in English [Hacking] |
13840 | First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking] |
13844 | A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking] |
13842 | Second-order completeness seems to need intensional entities and possible worlds [Hacking] |
13837 | With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking] |
13839 | Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking] |
13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
7621 | Special relativity, unlike general relativity, was operationalist in spirit [Putnam on Einstein] |
19423 | By an 'idea' I mean not an actual thought, but the resources we can draw on to think [Leibniz] |
22955 | Einstein took causation to be the bedrock of physics [Einstein, by Coveney/Highfield] |
20638 | General relativity assumes laws of nature are the same in all frames of reference [Einstein, by Close] |
20636 | Newton is a special case of Einstein's general theory, with an infinite speed of light [Einstein, by Close] |
21230 | The theory is 'special' because it sticks to observers moving straight, at constant speeds [Einstein, by Farmelo] |
21231 | Assume the speed of light is constant for all observers, and the laws of physics are the same [Einstein, by Farmelo] |
20634 | General Relativity says there is no absolute force or acceleration [Einstein, by Close] |
20648 | Mass is a measure of energy content [Einstein] |
21232 | Space-time arises from the connection between measurements of space and of time [Einstein, by Farmelo] |
7626 | I do not believe in a personal God [Einstein] |