9 ideas
9463 | Classical logic is bivalent, has excluded middle, and only quantifies over existent objects [Jacquette] |
Full Idea: Classical logic (of Whitehead, Russell, Gödel, Church) is a two-valued system of propositional and predicate logic, in which all propositions are exclusively true or false, and quantification and predication are over existent objects only. | |
From: Dale Jacquette (Intro to I: Classical Logic [2002], p.9) | |
A reaction: All of these get challenged at some point, though the existence requirement is the one I find dubious. |
21515 | Incoherence may be more important for enquiry than coherence [Olsson] |
Full Idea: While coherence may lack the positive role many have assigned to it, ...incoherence plays an important negative role in our enquiries. | |
From: Erik J. Olsson (Against Coherence [2005], 10.1) | |
A reaction: [He cites Peirce as the main source for this idea] We can hardly by deeply impressed by incoherence if we have no sense of coherence. Incoherence is just one of many markers for theory failure. Missing the target, bad concepts... |
21514 | Coherence is the capacity to answer objections [Olsson] |
Full Idea: According to Lehrer, coherence should be understood in terms of the capacity to answer objections. | |
From: Erik J. Olsson (Against Coherence [2005], 9) | |
A reaction: [Keith Lehrer 1990] We can connect this with the Greek requirement of being able to give an account [logos], which is the hallmark of understanding. I take coherence to be the best method of achieving understanding. Any understanding meets Lehrer's test. |
21496 | Mere agreement of testimonies is not enough to make truth very likely [Olsson] |
Full Idea: Far from guaranteeing a high likelihood of truth by itself, testimonial agreement can apparently do so only if the circumstances are favourable as regards independence, prior probability, and individual credibility. | |
From: Erik J. Olsson (Against Coherence [2005], 1) | |
A reaction: This is Olson's main thesis. His targets are C.I.Lewis and Bonjour, who hoped that a mere consensus of evidence would increase verisimilitude. I don't see a problem for coherence in general, since his favourable circumstances are part of it. |
21499 | Coherence is only needed if the information sources are not fully reliable [Olsson] |
Full Idea: An enquirer who is fortunate enough to have at his or her disposal fully reliable information sources has no use for coherence, the need for which arises only in the context of less than fully reliable informations sources. | |
From: Erik J. Olsson (Against Coherence [2005], 2.6.2) | |
A reaction: I take this to be entirely false. How do you assess reliability? 'I've seen it with my own eyes'. Why trust your eyes? In what visibility conditions do you begin to doubt your eyes? Why do rational people mistrust their intuitions? |
21502 | A purely coherent theory cannot be true of the world without some contact with the world [Olsson] |
Full Idea: The Input Objection says a pure coherence theory would seem to allow that a system of beliefs be justified in spite of being utterly out of contact with the world it purports to describe, so long as it is, to a sufficient extent, coherent. | |
From: Erik J. Olsson (Against Coherence [2005], 4.1) | |
A reaction: Olson seems impressed by this objection, but I don't see how a system could be coherently about the world if it had no known contact with the world. Olson seems to ignore meta-coherence, which evaluates the status of the system being studied. |
21512 | Extending a system makes it less probable, so extending coherence can't make it more probable [Olsson] |
Full Idea: Any non-trivial extension of a belief system is less probable than the original system, but there are extensions that are more coherent than the original system. Hence more coherence does not imply a higher probability. | |
From: Erik J. Olsson (Against Coherence [2005], 6.4) | |
A reaction: [Olson cites Klein and Warfield 1994; compressed] The example rightly says the extension could have high internal coherence, but not whether the extension is coherent with the system being extended. |
2384 | Those actions that follow immediately the last appetite are voluntary [Hobbes] |
Full Idea: Those actions that follow immediately the last appetite are voluntary. | |
From: Thomas Hobbes (Letters to the Lord Marquis of Newcastle [1652]) |
2385 | If a man suddenly develops an intention of doing something, the cause is out of his control, not in his will [Hobbes] |
Full Idea: When first a man hath an appetite or will to something, to which immediately before he had no appetite or will, the cause of his will is not the will itself, but something else not in his own disposing. | |
From: Thomas Hobbes (Letters to the Lord Marquis of Newcastle [1652]) |