10 ideas
| 11211 | If a sound conclusion comes from two errors that cancel out, the path of the argument must matter [Rumfitt] |
| Full Idea: If a designated conclusion follows from the premisses, but the argument involves two howlers which cancel each other out, then the moral is that the path an argument takes from premisses to conclusion does matter to its logical evaluation. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], II) | |
| A reaction: The drift of this is that our view of logic should be a little closer to the reasoning of ordinary language, and we should rely a little less on purely formal accounts. |
| 11210 | Standardly 'and' and 'but' are held to have the same sense by having the same truth table [Rumfitt] |
| Full Idea: If 'and' and 'but' really are alike in sense, in what might that likeness consist? Some philosophers of classical logic will reply that they share a sense by virtue of sharing a truth table. | |
| From: Ian Rumfitt ("Yes" and "No" [2000]) | |
| A reaction: This is the standard view which Rumfitt sets out to challenge. |
| 11212 | The sense of a connective comes from primitively obvious rules of inference [Rumfitt] |
| Full Idea: A connective will possess the sense that it has by virtue of its competent users' finding certain rules of inference involving it to be primitively obvious. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], III) | |
| A reaction: Rumfitt cites Peacocke as endorsing this view, which characterises the logical connectives by their rules of usage rather than by their pure semantic value. |
| 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. |
| 3102 | Why don't we experience or remember going to sleep at night? [Magee] |
| Full Idea: As a child it was incomprehensible to me that I did not experience going to sleep, and never remembered it. When my sister said 'Nobody remembers that', I just thought 'How does she know?' | |
| From: Bryan Magee (Confessions of a Philosopher [1997], Ch.I) | |
| A reaction: This is actually evidence for something - that we do not have some sort of personal identity which is separate from consciousness, so that "I am conscious" would literally mean that an item has a property, which it can lose. |
| 11214 | We learn 'not' along with affirmation, by learning to either affirm or deny a sentence [Rumfitt] |
| Full Idea: The standard view is that affirming not-A is more complex than affirming the atomic sentence A itself, with the latter determining its sense. But we could learn 'not' directly, by learning at once how to either affirm A or reject A. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], IV) | |
| A reaction: [compressed] This seems fairly anti-Fregean in spirit, because it looks at the psychology of how we learn 'not' as a way of clarifying what we mean by it, rather than just looking at its logical behaviour (and thus giving it a secondary role). |
| 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. |