18 ideas
| 1542 | Diogenes of Apollonia was the last natural scientist [Diogenes of Apollonia, by Simplicius] |
| 4187 | 'There is nothing without a reason why it should be rather than not be' (a generalisation of 'Why?') [Schopenhauer] |
| 17744 | De Morgan started the study of relations and their properties [De Morgan, by Walicki] |
| 13501 | De Morgan found inferences involving relations, which eluded Aristotle's syllogistic [De Morgan, by Hart,WD] |
| 489 | Each thing must be in some way unique [Diogenes of Apollonia] |
| 4192 | All necessity arises from causation, which is conditioned; there is no absolute or unconditioned necessity [Schopenhauer] |
| 4190 | All understanding is an immediate apprehension of the causal relation [Schopenhauer] |
| 483 | Start a thesis with something undisputable [Diogenes of Apollonia] |
| 1544 | Perception must be an internal matter, because we can fail to perceive when we are preoccupied [Diogenes of Apollonia, by Theophrastus] |
| 4191 | What we know in ourselves is not a knower but a will [Schopenhauer] |
| 21368 | The knot of the world is the use of 'I' to refer to both willing and knowing [Schopenhauer] |
| 24042 | The older Diogenes said the soul is air, made of the smallest particles [Diogenes of Apollonia] |
| 5995 | Diogenes of Apollonia offered the first teleological account of cosmology [Diogenes of Apollonia, by Robinson,TM] |
| 488 | Air is divine, because it is in and around everything, and arranges everything [Diogenes of Apollonia] |
| 484 | Everything is ultimately a variation of one underlying thing [Diogenes of Apollonia] |
| 486 | Plants and animals can only come into existence if something fixes their species [Diogenes of Apollonia] |
| 485 | Things must retain their essential nature during change, or mixing would be impossible [Diogenes of Apollonia] |
| 4189 | Time may be defined as the possibility of mutually exclusive conditions of the same thing [Schopenhauer] |