15 ideas
| 17896 | We need to know the meaning of 'and', prior to its role in reasoning [Prior,AN, by Belnap] |
| Full Idea: For Prior, so the moral goes, we must first have a notion of what 'and' means, independently of the role it plays as premise and as conclusion. | |
| From: report of Arthur N. Prior (The Runabout Inference Ticket [1960]) by Nuel D. Belnap - Tonk, Plonk and Plink p.132 | |
| A reaction: The meaning would be given by the truth tables (the truth-conditions), whereas the role would be given by the natural deduction introduction and elimination rules. This seems to be the basic debate about logical connectives. |
| 17898 | Prior's 'tonk' is inconsistent, since it allows the non-conservative inference A |- B [Belnap on Prior,AN] |
| Full Idea: Prior's definition of 'tonk' is inconsistent. It gives us an extension of our original characterisation of deducibility which is not conservative, since in the extension (but not the original) we have, for arbitrary A and B, A |- B. | |
| From: comment on Arthur N. Prior (The Runabout Inference Ticket [1960]) by Nuel D. Belnap - Tonk, Plonk and Plink p.135 | |
| A reaction: Belnap's idea is that connectives don't just rest on their rules, but also on the going concern of normal deduction. |
| 11021 | Prior rejected accounts of logical connectives by inference pattern, with 'tonk' his absurd example [Prior,AN, by Read] |
| Full Idea: Prior dislike the holism inherent in the claim that the meaning of a logical connective was determined by the inference patterns into which it validly fitted. ...His notorious example of 'tonk' (A → A-tonk-B → B) was a reductio of the view. | |
| From: report of Arthur N. Prior (The Runabout Inference Ticket [1960]) by Stephen Read - Thinking About Logic Ch.8 | |
| A reaction: [The view being attacked was attributed to Gentzen] |
| 13836 | Maybe introducing or defining logical connectives by rules of inference leads to absurdity [Prior,AN, by Hacking] |
| Full Idea: Prior intended 'tonk' (a connective which leads to absurdity) as a criticism of the very idea of introducing or defining logical connectives by rules of inference. | |
| From: report of Arthur N. Prior (The Runabout Inference Ticket [1960], §09) by Ian Hacking - What is Logic? |
| 6871 | We can't only believe things if we are currently conscious of their justification - there are too many [Goldman] |
| Full Idea: Strong internalism says only current conscious states can justify beliefs, but this has the problem of Stored Beliefs, that most of our beliefs are stored in memory, and one's conscious state includes nothing that justifies them. | |
| From: Alvin I. Goldman (Internalism Exposed [1999], §2) | |
| A reaction: This point seems obviously correct, but one could still have a 'fairly strong' version, which required that you could always call into consciousness the justificiation for any belief that you happened to remember. |
| 6872 | Internalism must cover Forgotten Evidence, which is no longer retrievable from memory [Goldman] |
| Full Idea: Even weak internalism has the problem of Forgotten Evidence; the agent once had adequate evidence that she subsequently forgot; at the time of epistemic appraisal, she no longer has adequate evidence that is retrievable from memory. | |
| From: Alvin I. Goldman (Internalism Exposed [1999], §3) | |
| A reaction: This is certainly a basic problem for any account of justification. It will rule out any strict requirement that there be actual mental states available to support a belief. Internalism may be pushed to include non-conscious parts of the mind. |
| 6874 | Internal justification needs both mental stability and time to compute coherence [Goldman] |
| Full Idea: The problem for internalists of Doxastic Decision Interval says internal justification must avoid mental change to preserve the justification status, but must also allow enough time to compute the formal relations between beliefs. | |
| From: Alvin I. Goldman (Internalism Exposed [1999], §4) | |
| A reaction: The word 'compute' implies a rather odd model of assessing coherence, which seems instantaneous for most of us where everyday beliefs are concerned. In real mental life this does not strike me as a problem. |
| 6873 | Coherent justification seems to require retrieving all our beliefs simultaneously [Goldman] |
| Full Idea: The problem of Concurrent Retrieval is a problem for internalism, notably coherentism, because an agent could ascertain coherence of her entire corpus only by concurrently retrieving all of her stored beliefs. | |
| From: Alvin I. Goldman (Internalism Exposed [1999], §3) | |
| A reaction: Sounds neat, but not very convincing. Goldman is relying on scepticism about short-term memory, but all belief and knowledge will collapse if we go down that road. We couldn't do simple arithmetic if Goldman's point were right. |
| 6875 | Reliability involves truth, and truth is external [Goldman] |
| Full Idea: Reliability involves truth, and truth (on the usual assumption) is external. | |
| From: Alvin I. Goldman (Internalism Exposed [1999], §6) | |
| A reaction: As an argument for externalism this seems bogus. I am not sure that truth is either 'internal' or 'external'. How could the truth of 3+2=5 be external? Facts are mostly external, but I take truth to be a relation between internal and external. |
| 17064 | 1: Coherence is a symmetrical relation between two propositions [Thagard, by Smart] |
| Full Idea: 1: Coherence and incoherence are symmetrical between pairs of propositions. | |
| From: report of Paul Thagard (Explanatory Coherence [1989], 1) by J.J.C. Smart - Explanation - Opening Address p.04 |
| 17065 | 2: An explanation must wholly cohere internally, and with the new fact [Thagard, by Smart] |
| Full Idea: 2: If a set of propositions explains a further proposition, then each proposition in the set coheres with that proposition, and propositions in the set cohere pairwise with one another. | |
| From: report of Paul Thagard (Explanatory Coherence [1989], 2) by J.J.C. Smart - Explanation - Opening Address p.04 |
| 17066 | 3: If an analogous pair explain another analogous pair, then they all cohere [Thagard, by Smart] |
| Full Idea: 3: If two analogous propositions separately explain different ones of a further pair of analogous propositions, then the first pair cohere with one another, and so do the second (explananda) pair. | |
| From: report of Paul Thagard (Explanatory Coherence [1989], 3) by J.J.C. Smart - Explanation - Opening Address p.04 |
| 17067 | 4: For coherence, observation reports have a degree of intrinsic acceptability [Thagard, by Smart] |
| Full Idea: 4: Observation reports (for coherence) have a degree of acceptability on their own. | |
| From: report of Paul Thagard (Explanatory Coherence [1989], 4) by J.J.C. Smart - Explanation - Opening Address p.04 | |
| A reaction: Thagard makes this an axiom, but Smart rejects that and says there is no reason why observation reports should not also be accepted because of their coherence (with our views about our senses etc.). I agree with Smart. |
| 17068 | 5: Contradictory propositions incohere [Thagard, by Smart] |
| Full Idea: 5: Contradictory propositions incohere. | |
| From: report of Paul Thagard (Explanatory Coherence [1989], 5) by J.J.C. Smart - Explanation - Opening Address p.04 | |
| A reaction: This has to be a minimal axiom for coherence, but coherence is always taken to be more than mere logical consistency. Mutual relevance is the first step. At least there must be no category mistakes. |
| 17069 | 6: A proposition's acceptability depends on its coherence with a system [Thagard, by Smart] |
| Full Idea: 6: Acceptability of a proposition in a system depends on its coherence with the propositions in that system. | |
| From: report of Paul Thagard (Explanatory Coherence [1989], 6) by J.J.C. Smart - Explanation - Opening Address p.04 | |
| A reaction: Thagard tried to build an AI system for coherent explanations, but I would say he has no chance with these six axioms, because they never grasp the nettle of what 'coherence' means. You first need rules for how things relate. What things are comparable? |