29 ideas
10775 | The axiom of choice now seems acceptable and obvious (if it is meaningful) [Tharp] |
10766 | Logic is either for demonstration, or for characterizing structures [Tharp] |
10767 | Elementary logic is complete, but cannot capture mathematics [Tharp] |
10769 | Second-order logic isn't provable, but will express set-theory and classic problems [Tharp] |
10762 | In sentential logic there is a simple proof that all truth functions can be reduced to 'not' and 'and' [Tharp] |
10776 | The main quantifiers extend 'and' and 'or' to infinite domains [Tharp] |
10774 | There are at least five unorthodox quantifiers that could be used [Tharp] |
10777 | Skolem mistakenly inferred that Cantor's conceptions were illusory [Tharp] |
10773 | The Löwenheim-Skolem property is a limitation (e.g. can't say there are uncountably many reals) [Tharp] |
10765 | Soundness would seem to be an essential requirement of a proof procedure [Tharp] |
10763 | Completeness and compactness together give axiomatizability [Tharp] |
10770 | If completeness fails there is no algorithm to list the valid formulas [Tharp] |
10771 | Compactness is important for major theories which have infinitely many axioms [Tharp] |
10772 | Compactness blocks infinite expansion, and admits non-standard models [Tharp] |
10764 | A complete logic has an effective enumeration of the valid formulas [Tharp] |
10768 | Effective enumeration might be proved but not specified, so it won't guarantee knowledge [Tharp] |
8203 | All the arithmetical entities can be reduced to classes of integers, and hence to sets [Quine] |
7621 | Special relativity, unlike general relativity, was operationalist in spirit [Putnam on Einstein] |
8202 | Meaning is essence divorced from things and wedded to words [Quine] |
8201 | The distinction between meaning and further information is as vague as the essence/accident distinction [Quine] |
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] |
21231 | Assume the speed of light is constant for all observers, and the laws of physics are the same [Einstein, by Farmelo] |
21230 | The theory is 'special' because it sticks to observers moving straight, at constant speeds [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] |