14 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. |
| 13931 | By using aporiai as his start, Aristotle can defer to the wise, as well as to the many [Haslanger] |
| Full Idea: The Aristotelian method of working form aporia allows one to use as starting points not only what is said by 'the many', but also what is said by 'the wise', including philosophers. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 1 n2) | |
| A reaction: [She mentions Nussbaum 1986:ch 7 for the opposing view] I like this thought a lot. Aristotle's democratic respect for widespread views can be a bit puzzling sometimes. |
| 15938 | Platonists ruin infinity, which is precisely a growing structure which is never completed [Dummett] |
| Full Idea: The platonist destroys the whole essence of infinity, which lies in the conception of a structure which is always in growth, precisely because the process of construction is never completed. | |
| From: Michael Dummett (Elements of Intuitionism [1977], p.57), quoted by Thomas J. McKay - Plural Predication | |
| A reaction: I don't warm to intuitionism, but I warm to this conception of infinity. Completed infinities are convenient reifications for mathematicians. |
| 15939 | For intuitionists it is constructed proofs (which take time) which make statements true [Dummett] |
| Full Idea: For an intuitionist a mathematical statement is rendered true or false by a proof or disproof, that is, by a construction, and constructions are effected in time. | |
| From: Michael Dummett (Elements of Intuitionism [1977], p.336), quoted by Shaughan Lavine - Understanding the Infinite VI.2 | |
| A reaction: Lavine is quoting this to draw attention to the difficulties of thinking of it as all taking place 'in time', especially when dealing with infinities. |
| 13925 | Ontology disputes rest on more basic explanation disputes [Haslanger] |
| Full Idea: Disputes over ontology derive from more fundamental disputes over forms of explanation. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 1) | |
| A reaction: It immediately strikes me that Haslanger has stolen my master idea, but unfortunately the dating suggests that she has priority. The tricky part is to combine this view with realism. |
| 13924 | The persistence of objects seems to be needed if the past is to explain the present [Haslanger] |
| Full Idea: The notion that things persist through change is deeply embedded in ideas we have about explanation, and in particular, in the idea that the present is constrained by the past. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 1) | |
| A reaction: I take this to be both an important and an attractive idea. Deniers of persistence (4D-ists) will presumably have some ability to explain the present, but it is the idea of the present being 'constrained' by the past which is a challenge. |
| 13930 | Persistence makes change and its products intelligible [Haslanger] |
| Full Idea: Persistence offers intelligibility: the possibility of understanding a change, and of understanding the products of it. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 8) | |
| A reaction: I think this is exactly right, and it is a powerful idea with wide implications for metaphysics. Haslanger claims that an understanding of 'substance' is needed, which leads towards my defence of essentialism. |
| 13927 | We must explain change amongst 'momentary entities', or else the world is inexplicable [Haslanger] |
| Full Idea: If the world of time-slices is to be explicable, then it must be possible to provide explanations of change understood as a continual generation and destruction of these 'momentary entities'. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 7) | |
| A reaction: While fans of time-slices can offer some sort of explanation, in the process of explaining a 'worm', there don't seem to be the sort of causal chains that we traditionally rely on. Maybe there are no explanations of anything? |
| 13928 | If the things which exist prior to now are totally distinct, they need not have existed [Haslanger] |
| Full Idea: How is the case in which A exists prior to B, but is distinct from B, different (especially from B's point of view) from the case in which nothing exists prior to B? | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 7) | |
| A reaction: I sympathise with her view, but this isn't persuasive. For A substitute 'Sally's mother' and for B substitute 'Sally'. A 4D-ist could bite the bullet and say that, indeed, previous parts of my 'worm' need not have existed. |
| 13929 | Natural explanations give the causal interconnections [Haslanger] |
| Full Idea: Natural explanations work by showing the systematic causal interconnections between things. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 7) | |
| A reaction: On the whole I love this sort of idea, but I am wondering if this one prevents mathematical or logical explanations from being natural. |
| 13926 | Best explanations, especially natural ones, need grounding, notably by persistent objects [Haslanger] |
| Full Idea: I am not resting my ontology on a simple 'argument to the best explanation'. ..What I want to say is that there are general demands on a kind of explanation, in particular, natural explanation, which require that there are persisting things. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 5) | |
| A reaction: This is a really nice idea - that best explanation is not just about specific cases, but also about best foundations for explanations in general, which brings in our metaphysics. I defend the role of essences in these best explanations. |
| 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). |