25 ideas
| 9271 | Human knowledge may not produce well-being; the examined life may not be worth living [Gray] |
| 8623 | Proof reveals the interdependence of truths, as well as showing their certainty [Euclid, by Frege] |
| 13907 | If you pick an arbitrary triangle, things proved of it are true of all triangles [Euclid, by Lemmon] |
| 6297 | Euclid's geometry is synthetic, but Descartes produced an analytic version of it [Euclid, by Resnik] |
| 9603 | An assumption that there is a largest prime leads to a contradiction [Euclid, by Brown,JR] |
| 9894 | A unit is that according to which each existing thing is said to be one [Euclid] |
| 8738 | Postulate 2 says a line can be extended continuously [Euclid, by Shapiro] |
| 22278 | Euclid relied on obvious properties in diagrams, as well as on his axioms [Potter on Euclid] |
| 8673 | Euclid's parallel postulate defines unique non-intersecting parallel lines [Euclid, by Friend] |
| 10250 | Euclid needs a principle of continuity, saying some lines must intersect [Shapiro on Euclid] |
| 10302 | Euclid says we can 'join' two points, but Hilbert says the straight line 'exists' [Euclid, by Bernays] |
| 14157 | Modern geometries only accept various parts of the Euclid propositions [Russell on Euclid] |
| 1600 | Euclid's common notions or axioms are what we must have if we are to learn anything at all [Euclid, by Roochnik] |
| 9275 | Knowledge does not need minds or nervous systems; it is found in all living things [Gray] |
| 9276 | The will hardly ever does anything; most of our life just happens to us [Gray] |
| 3032 | I can form no notion of what the good is [Amphis] |
| 9278 | Nowadays we identify the free life with the good life [Gray] |
| 9280 | Over forty percent of the Earth's living tissue is human [Gray] |
| 23061 | Free atheism should start by questioning its faith in humanity [Gray] |
| 23057 | Gnosticism has a supreme creator God, giving way to a possibly hostile Demiurge [Gray] |
| 23056 | Judaism only became monotheistic around 550 BCE [Gray] |
| 23055 | Christians introduced the idea that a religion needs a creed [Gray] |
| 9279 | What was our original sin, and how could Christ's suffering redeem it? [Gray] |
| 9272 | Without Christianity we lose the idea that human history has a meaning [Gray] |
| 23058 | Buddhism has no divinity or souls, and the aim is to lose the illusion of a self [Gray] |