6 ideas
| 13197 | The notion of substance is one of the keys to true philosophy [Leibniz] |
| Full Idea: I consider the notion of substance to be one of the keys to the true philosophy. ....I imagine that philosophers will one day know the notion of substance a bit better than they do now. | |
| From: Gottfried Leibniz (Letters to Thomas Burnett [1703], 1699.01.20/30) | |
| A reaction: This is a controversial remark at this historical moment, when the apparent Aristotelian commitment to substances was becoming discredited. Personally I would eliminate substance, but not just because physicists don't refer to it. |
| 5987 | Alcmaeon was the first to say the brain is central to thinking [Alcmaeon, by Staden, von] |
| Full Idea: Alcmaeon apparently was the first Greek to assign central cognitive and biological functions to the brain. | |
| From: report of Alcmaeon (fragments/reports [c.490 BCE]) by Heinrich von Staden - Alcmaeon | |
| A reaction: The name of Alcmaeon should be remembered with honour. This was 200 years before Aristotle, who still hadn't worked it out. I presume Alcmaeon inferred the truth from head injuries, which is overwhelming evidence, if you notice it. |
| 13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
| Full Idea: In a single day there lies open to men of learning more than there ever does to the unenlightened in the longest of lifetimes. | |
| From: Posidonius (fragments/reports [c.95 BCE]), quoted by Seneca the Younger - Letters from a Stoic 078 | |
| A reaction: These remarks endorsing the infinite superiority of the educated to the uneducated seem to have been popular in late antiquity. It tends to be the religions which discourage great learning, especially in their emphasis on a single book. |
| 13198 | Gravity is within matter because of its structure, and it can be explained. [Leibniz] |
| Full Idea: I believe that both gravity and elasticity are in matter only because of the structure of the system and can be explained mechanically or through impulsion. | |
| From: Gottfried Leibniz (Letters to Thomas Burnett [1703], 1699 draft) | |
| A reaction: The significance of this remark is that gravity is held (in full knowledge of Newton's work) to be within matter, and not imposed from the outside. I believe we now postulate a particle as part of the explanation. |
| 20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
| Full Idea: Posidonius defined time thus: it is an interval of motion, or the measure of speed and slowness. | |
| From: report of Posidonius (fragments/reports [c.95 BCE]) by John Stobaeus - Anthology 1.08.42 | |
| A reaction: Hm. Can we define motion or speed without alluding to time? Looks like we have to define them as a conjoined pair, which means we cannot fully understand either of them. |
| 24043 | Soul must be immortal, since it continually moves, like the heavens [Alcmaeon, by Aristotle] |
| Full Idea: Alcmaeon says that the soul is immortal because it resembles immortal things and that this affection belongs to it because it is always in movement, like divine things, such the moon, the sun, the stars and the whole heaven. | |
| From: report of Alcmaeon (fragments/reports [c.490 BCE], DK 24) by Aristotle - De Anima 405a30 | |
| A reaction: Hm. Fish and rivers seem to be continually moving too. Presumably we are like gods, but then Greek gods seem awfully like humans. I don't know the history of belief in immortality; an interesting topic. |