20 ideas
| 17641 | Discoveries in mathematics can challenge philosophy, and offer it a new foundation [Russell] |
| 17638 | If one proposition is deduced from another, they are more certain together than alone [Russell] |
| 17632 | Non-contradiction was learned from instances, and then found to be indubitable [Russell] |
| 15533 | We can quantify over fictions by quantifying for real over their names [Lewis] |
| 15534 | We could quantify over impossible objects - as bundles of properties [Lewis] |
| 17629 | Which premises are ultimate varies with context [Russell] |
| 17630 | The sources of a proof are the reasons why we believe its conclusion [Russell] |
| 17640 | Finding the axioms may be the only route to some new results [Russell] |
| 17627 | It seems absurd to prove 2+2=4, where the conclusion is more certain than premises [Russell] |
| 17628 | Arithmetic was probably inferred from relationships between physical objects [Russell] |
| 15532 | 'Allists' embrace the existence of all controversial entities; 'noneists' reject all but the obvious ones [Lewis] |
| 15535 | We can't accept a use of 'existence' that says only some of the things there are actually exist [Lewis] |
| 9295 | Not only substances have attributes; events, actions, states and qualities can have them [Teichmann] |
| 17637 | The most obvious beliefs are not infallible, as other obvious beliefs may conflict [Russell] |
| 17639 | Believing a whole science is more than believing each of its propositions [Russell] |
| 17631 | Induction is inferring premises from consequences [Russell] |
| 9293 | Body-spirit interaction ought to result in losses and increases of energy in the material world [Teichmann] |
| 17633 | The law of gravity has many consequences beyond its grounding observations [Russell] |
| 9292 | The Soul has no particular capacity (in the way thinking belongs to the mind) [Teichmann] |
| 9294 | No individuating marks distinguish between Souls [Teichmann] |