11 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. |
23651 | Universals are not objects of sense and cannot be imagined - but can be conceived [Reid] |
Full Idea: A universal is not an object of any sense, and therefore cannot be imagined; but it may be distinctly conceived. | |
From: Thomas Reid (Essays on Intellectual Powers 5: Abstraction [1785], 6) | |
A reaction: If you try to imagine whiteness, what size is it, and what substance embodies it? Neither are needed to think of whiteness, so Reid is right. A nice observation. |
23650 | Only individuals exist [Reid] |
Full Idea: Everything that really exists is an individual. | |
From: Thomas Reid (Essays on Intellectual Powers 5: Abstraction [1785], 6) | |
A reaction: Locke is the probable inspiration for this nominalist affirmation. Not sure how high temperature plasma, or the oceans of the world, fit into this. On the whole I agree with him. He is mainly rejecting abstract universals. |
23649 | No one thinks two sheets possess a single whiteness, but all agree they are both white [Reid] |
Full Idea: If we say that the whiteness of this sheet is the whiteness of another sheet, every man perceives this to be absurd; but when he says both sheets are white, this is true and perfectly understood. | |
From: Thomas Reid (Essays on Intellectual Powers 5: Abstraction [1785], 3) | |
A reaction: Well said. Only a philosopher could think the whiteness of one sheet is exactly the same entity as the whiteness of a different sheet. We seem to have brilliantly and correctly labelled them both as white, and then thought that one word implies one thing. |
11874 | Real identity admits of no degrees [Reid] |
Full Idea: Wherever identity is real, it admits of no degrees. | |
From: Thomas Reid (Essays on Intellectual Powers 5: Abstraction [1785]), quoted by David Wiggins - Sameness and Substance Renewed 6 epig | |
A reaction: Wiggins quotes this with strong approval. Personally I am inclined to think that identity may admit of no degrees in human thought, because that is the only way we can do it, but the world is full of uncertain identities, at every level. |
23652 | We must first conceive things before we can consider them [Reid] |
Full Idea: No man can consider a thing which he does not conceive. | |
From: Thomas Reid (Essays on Intellectual Powers 5: Abstraction [1785], 6) | |
A reaction: This seems to imply concepts, but we should not take this to be linguistic, since animals obviously consider things and make judgements. |
23648 | First we notice and name attributes ('abstracting'); then we notice that subjects share them ('generalising') [Reid] |
Full Idea: First we resolve or analyse a subject into its known attributes, and give a name to each attribute. Then we observe one or more attributes to be common to many subjects. The first philosophers call 'abstraction', and the second is 'generalising'. | |
From: Thomas Reid (Essays on Intellectual Powers 5: Abstraction [1785], 3) | |
A reaction: It is very unfashionable in analytic philosophy to view universals in this way, but it strikes me as obviously correct. There are not weird abstract entities awaiting a priori intuition. There are just features of the world to be observed and picked out. |
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). |
21058 | Enlightenment requires the free use of reason in the public realm [Kant] |
Full Idea: The public use of man's reason must always be free, and it alone can bring about enlightenment among men; the private use of reason may quite often be very narrowly restricted (…in a particular civil post or office). | |
From: Immanuel Kant (Answer to 'What is Enlightenment?' [1784], p.55) | |
A reaction: The private aspect seems to be the common restriction on speech by employees of the state. Does free speech have only instrumental value? Is the life of virtue possible without it? |