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. |
| 10414 | Abstract objects are constituted by encoded collections of properties [Zalta, by Swoyer] |
| Full Idea: In Zalta's view abstract objects are correlated with collections of properties. ..They encode, as well as exemplify, properties; indeed, an abstract object (such as a Euclidean triangle) is constituted by the properties it encodes. | |
| From: report of Edward N. Zalta (Abstract Objects:intro to Axiomatic Metaphysics [1983]) by Chris Swoyer - Properties 6.3 | |
| A reaction: If we are going to explain abstract objects with properties, then properties had better not be abstract objects. Zalta has a promising idea if we start from a nominalist and naturalistic view of properties (built from physical powers). 'Encode'? |
| 10415 | Properties make round squares and round triangles distinct, unlike exemplification [Zalta, by Swoyer] |
| Full Idea: On Zalta's view, properties with the same encoding extensions are identical, but may be distinct with the same exemplification extension. So the properties of being a round square and a round triangle are distinct, but with the same exemplification. | |
| From: report of Edward N. Zalta (Abstract Objects:intro to Axiomatic Metaphysics [1983]) by Chris Swoyer - Properties | |
| A reaction: (For Zalta's view, see Idea 10414) I'm not sure about 'encoding' (cf. Hodes's use of the word), but the idea that an abstract object is just a bunch of possible properties (assuming properties have prior availability) seems promising. |
| 23633 | Many truths seem obvious, and point to universal agreement - which is what we find [Reid] |
| Full Idea: There are many truths so obvious to the human faculties, that it should be expected that men should universally agree in them. And this is actually found to be the case with regard to many truths, against which we find no dissent. | |
| From: Thomas Reid (Essays on Intellectual Powers 1: Preliminary [1785], 2) | |
| A reaction: He says that a few sceptical philosophers may disagree. This is a nice statement of his creed of common sense. I agree with him, and Aristotle observes the same fact. |
| 23630 | Only philosophers treat ideas as objects [Reid] |
| Full Idea: The vulgar allow that an 'idea' implies a mind that thinks, an act of mind which we call thinking, and an object about which we think. But the philosopher conceives a fourth - the idea, which is the immediate object. …I believe this to be a mere fiction. | |
| From: Thomas Reid (Essays on Intellectual Powers 1: Preliminary [1785], 1) | |
| A reaction: Another example, to add to Yablo's list, of abstract objects invented by philosophers to fill holes in their theories. This one is illuminating, because we all say 'I've got an idea'. Cf discussions of the redundancy of truth. Cf propositions. |
| 23629 | The ambiguity of words impedes the advancement of knowledge [Reid] |
| Full Idea: There is no greater impediment to the advancement of knowledge than the ambiguity of words. | |
| From: Thomas Reid (Essays on Intellectual Powers 1: Preliminary [1785], 1) | |
| A reaction: He means that ambiguity leads to long pointless disagreements. |
| 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). |
| 23632 | Similar effects come from similar causes, and causes are only what are sufficient for the effects [Reid] |
| Full Idea: A first principle is that similar effects proceed from the same or similar causes; that we ought to admit of no other causes …but such as are sufficient to account for the effects. | |
| From: Thomas Reid (Essays on Intellectual Powers 1: Preliminary [1785], 2) | |
| A reaction: He treats these as a priori axioms of natural philosophy. In evolution similar causes seem to produce startlingly divergent effects, such as the mating needs of male birds. |