39 ideas
14239 | The empty set is usually derived from Separation, but it also seems to need Infinity [Oliver/Smiley] |
14240 | The empty set is something, not nothing! [Oliver/Smiley] |
14241 | We don't need the empty set to express non-existence, as there are other ways to do that [Oliver/Smiley] |
14242 | Maybe we can treat the empty set symbol as just meaning an empty term [Oliver/Smiley] |
14243 | The unit set may be needed to express intersections that leave a single member [Oliver/Smiley] |
14234 | If you only refer to objects one at a time, you need sets in order to refer to a plurality [Oliver/Smiley] |
14237 | We can use plural language to refer to the set theory domain, to avoid calling it a 'set' [Oliver/Smiley] |
14245 | Logical truths are true no matter what exists - but predicate calculus insists that something exists [Oliver/Smiley] |
14246 | If mathematics purely concerned mathematical objects, there would be no applied mathematics [Oliver/Smiley] |
14247 | Sets might either represent the numbers, or be the numbers, or replace the numbers [Oliver/Smiley] |
17405 | If a theory can be fudged, so can observations [Scerri] |
17397 | The periodic system is the big counterexample to Kuhn's theory of revolutionary science [Scerri] |
17393 | Scientists eventually seek underlying explanations for every pattern [Scerri] |
17403 | The periodic table suggests accommodation to facts rates above prediction [Scerri] |
17394 | Natural kinds are what are differentiated by nature, and not just by us [Scerri] |
17421 | If elements are natural kinds, might the groups of the periodic table also be natural kinds? [Scerri] |
17396 | The colour of gold is best explained by relativistic effects due to fast-moving inner-shell electrons [Scerri] |
17420 | The stability of nuclei can be estimated through their binding energy [Scerri] |
17411 | If all elements are multiples of one (of hydrogen), that suggests once again that matter is unified [Scerri] |
17407 | The electron is the main source of chemical properties [Scerri] |
17415 | A big chemistry idea is that covalent bonds are shared electrons, not transfer of electrons [Scerri] |
17392 | How can poisonous elements survive in the nutritious compound they compose? [Scerri] |
17391 | Periodicity and bonding are the two big ideas in chemistry [Scerri] |
17404 | Chemistry does not work from general principles, but by careful induction from large amounts of data [Scerri] |
17409 | Does radioactivity show that only physics can explain chemistry? [Scerri] |
17418 | It is now thought that all the elements have literally evolved from hydrogen [Scerri] |
17398 | 19th C views said elements survived abstractly in compounds, but also as 'material ingredients' [Scerri] |
17406 | Moseley, using X-rays, showed that atomic number ordered better than atomic weight [Scerri] |
17408 | Some suggested basing the new periodic table on isotopes, not elements [Scerri] |
17412 | Elements are placed in the table by the number of positive charges - the atomic number [Scerri] |
17413 | Elements in the table are grouped by having the same number of outer-shell electrons [Scerri] |
17416 | Orthodoxy says the periodic table is explained by quantum mechanics [Scerri] |
17414 | Pauli explained the electron shells, but not the lengths of the periods in the table [Scerri] |
17410 | Moseley showed the elements progress in units, and thereby clearly identified the gaps [Scerri] |
17395 | Elements were ordered by equivalent weight; later by atomic weight; finally by atomic number [Scerri] |
17422 | The best classification needs the deepest and most general principles of the atoms [Scerri] |
17417 | To explain the table, quantum mechanics still needs to explain order of shell filling [Scerri] |
17419 | Since 99.96% of the universe is hydrogen and helium, the periodic table hardly matters [Scerri] |
3029 | Stilpo said if Athena is a daughter of Zeus, then a statue is only the child of a sculptor, and so is not a god [Stilpo, by Diog. Laertius] |