8 ideas
| 18091 | Infinitesimals are ghosts of departed quantities [Berkeley] |
| Full Idea: The infinitesimals are the ghosts of departed quantities. | |
| From: George Berkeley (The Analyst [1734]), quoted by David Bostock - Philosophy of Mathematics 4.3 | |
| A reaction: [A famous phrase, but as yet no context for it] |
| 13168 | My formal unifying atoms are substantial forms, which are forces like appetites [Leibniz] |
| Full Idea: To find real entities I had recourse to a unified formal atom. Hence I rehabilitated the substantial forms in a way to render them intelligible. I found that their nature consists in force, from which follows something analogous to sensation and appetite. | |
| From: Gottfried Leibniz (New system of communication of substances [1695], p.139) | |
| A reaction: [several lines are here compressed] This passage sums up the key to Leibniz's essentialism, which I take to be a connection between Aristotelian form and the physicists' notion of force. This gives us a modern version of Aristotelianism for science. |
| 13169 | I call Aristotle's entelechies 'primitive forces', which originate activity [Leibniz] |
| Full Idea: Forms establish the true general principles of nature. Aristotle calls them 'first entelechies'; I call them, perhaps more intelligibly, 'primitive forces', which contain not only act or the completion of possibility, but also an original activity. | |
| From: Gottfried Leibniz (New system of communication of substances [1695], p.139) | |
| A reaction: As in Idea 13168, I take Leibniz to be unifying Aristotle with modern science, and offering an active view of nature in tune with modern scientific essentialism. Laws arise from primitive force, and are not imposed from without. |
| 13170 | The analysis of things leads to atoms of substance, which found both composition and action [Leibniz] |
| Full Idea: There are only atoms of substance, that is, real unities absolutely destitute of parts, which are the source of actions, the first absolute principles of the composition of things, and, as it were, the final elements in the analysis of substantial things. | |
| From: Gottfried Leibniz (New system of communication of substances [1695], p.142) | |
| A reaction: I like this because it addresses the pure issue of the identity of an individuated object, but also links it with an active view of nature, and not some mere inventory of objects. |
| 13171 | Substance must necessarily involve progress and change [Leibniz] |
| Full Idea: The nature of substance necessarily requires and essentially involves progress or change, without which it would not have the force to act. | |
| From: Gottfried Leibniz (New system of communication of substances [1695], p.144) | |
| A reaction: Bravo. Most metaphysical musings regarding 'substance' seem entirely wrapped up in the problem of pure identity, and forget about the role of objects in activity and change. |
| 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. |
| 13167 | We need the metaphysical notion of force to explain mechanics, and not just extended mass [Leibniz] |
| Full Idea: Considering 'extended mass' alone was not sufficient to explain the principles of mechanics and the laws of nature, but it is necessary to make use of the notion of 'force', which is very intelligible, despite belonging in the domain of metaphysics. | |
| From: Gottfried Leibniz (New system of communication of substances [1695], p.139) | |
| A reaction: We may find it surprising that force is a metaphysical concept, but that is worth pondering. It is a mysterious notion within physics. Notice the emphasis on what explains, and what is intelligible. He sees Descartes's system as too passive. |
| 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. |