6 ideas
23476 | Logical constants seem to be entities in propositions, but are actually pure form [Russell] |
Full Idea: 'Logical constants', which might seem to be entities occurring in logical propositions, are really concerned with pure form, and are not actually constituents of the propositions in the verbal expressions of which their names occur. | |
From: Bertrand Russell (The Theory of Knowledge [1913], 1.IX) | |
A reaction: This seems to entirely deny the existence of logical constants, and yet he says that they are named. Russell was obviously under pressure here from Wittgenstein. |
23477 | We use logical notions, so they must be objects - but I don't know what they really are [Russell] |
Full Idea: Such words as or, not, all, some, plainly involve logical notions; since we use these intelligently, we must be acquainted with the logical objects involved. But their isolation is difficult, and I do not know what the logical objects really are. | |
From: Bertrand Russell (The Theory of Knowledge [1913], 1.IX) | |
A reaction: See Idea 23476, from the previous page. Russell is struggling. Wittgenstein was telling him that the constants are rules (shown in truth tables), rather than objects. |
18273 | Logical truths are known by their extreme generality [Russell] |
Full Idea: A touchstone by which logical propositions may be distinguished from all others is that they result from a process of generalisation which has been carried to its utmost limits. | |
From: Bertrand Russell (The Theory of Knowledge [1913], p.129), quoted by J. Alberto Coffa - The Semantic Tradition from Kant to Carnap 7 'What' |
22315 | There can't be a negative of a complex, which is negated by its non-existence [Potter on Russell] |
Full Idea: On Russell's pre-war conception it is obvious that a complex cannot be negative. If a complex were true, what would make it false would be its non-existence, not the existence of some other complex. | |
From: comment on Bertrand Russell (The Theory of Knowledge [1913]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 41 'Neg' | |
A reaction: It might be false because it doesn't exist, but also 'made' false by a rival complex (such as Desdemona loving Othello). |
16597 | Quantity is the capacity to be divided [Digby] |
Full Idea: Quantity …is divisibility, or a capacity to be divided into parts. | |
From: Kenelm Digby (Two treatises [1644], I.2.8), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 04.1 | |
A reaction: 'Quantity' is scholastic philosophy is a concept we no longer possess. Without quantity, a thing might potentially exist at a spaceless point. Quantity is what spreads things out. See Pasnau Ch. 4. |
16731 | Colours arise from the rarity, density and mixture of matter [Digby] |
Full Idea: The origin of all colours in bodies is plainly deduced out of the various degrees of rarity and density, variously mixed and compounded. | |
From: Kenelm Digby (Two treatises [1644], I.29.4), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 22.5 | |
A reaction: We are still struggling with this question, though I think the picture is gradually become clear, once you get the hang of the brain. Easy! See Idea 17396. |