10 ideas
| 6950 | You can be rational with undetected or minor inconsistencies [Harman] |
| Full Idea: Rationality doesn't require consistency, because you can be rational despite undetected inconsistencies in beliefs, and it isn't always rational to respond to a discovery of inconsistency by dropping everything in favour of eliminating that inconsistency. | |
| From: Gilbert Harman (Rationality [1995], 1.2) | |
| A reaction: This strikes me as being correct, and is (I am beginning to realise) a vital contribution made to our understanding by pragmatism. European thinking has been too keen on logic as the model of good reasoning. |
| 6954 | A coherent conceptual scheme contains best explanations of most of your beliefs [Harman] |
| Full Idea: A set of unrelated beliefs seems less coherent than a tightly organized conceptual scheme that contains explanatory principles that make sense of most of your beliefs; this is why inference to the best explanation is an attractive pattern of inference. | |
| From: Gilbert Harman (Rationality [1995], 1.5.2) | |
| A reaction: I find this a very appealing proposal. The central aim of rational thought seems to me to be best explanation, and I increasingly think that most of my beliefs rest on their apparent coherence, rather than their foundations. |
| 14303 | Truth-functional conditionals have a simple falsification, when A is true and B is false [Peirce] |
| Full Idea: The utility of [truth-functional conditionals] is that it puts us in possession of a rule...[namely] The hypothetical proposition may be ...falsified by a single state of things, but only by one in which A [antecedent] is true and B [consequent] is false. | |
| From: Charles Sanders Peirce (On the Algebra of Logic [1895], p.218), quoted by Stephen Mumford - Dispositions | |
| A reaction: Personally I am rather more interested in verifying conditionals than in falsifying them. I certainly don't accept them until they are falsified, unless they have massive support from surrounding facts. |
| 6955 | Enumerative induction is inference to the best explanation [Harman] |
| Full Idea: We might think of enumerative induction as inference to the best explanation, taking the generalization to explain its instances. | |
| From: Gilbert Harman (Rationality [1995], 1.5.2) | |
| A reaction: This is a helpful connection. The best explanation of these swans being white is that all swans are white; it ceased to be the best explanation when black swans turned up. In the ultimate case, a law of nature is the explanation. |
| 6952 | Induction is 'defeasible', since additional information can invalidate it [Harman] |
| Full Idea: It is sometimes said that inductive reasoning is 'defeasible', meaning that considerations that support a given conclusion can be defeated by additional information. | |
| From: Gilbert Harman (Rationality [1995], 1.4.5) | |
| A reaction: True. The point is that being defeasible does not prevent such thinking from being rational. The rational part of it is to acknowledge that your conclusion is defeasible. |
| 6953 | All reasoning is inductive, and deduction only concerns implication [Harman] |
| Full Idea: Deductive logic is concerned with deductive implication, not deductive reasoning; all reasoning is inductive | |
| From: Gilbert Harman (Rationality [1995], 1.4.5) | |
| A reaction: This may be an attempt to stipulate how the word 'reasoning' should be used in future. It is, though, a bold and interesting claim, given the reputation of induction (since Hume) of being a totally irrational process. |
| 22371 | Determinism threatens free will if actions can be causally traced to external factors [Foot] |
| Full Idea: The determinism which worries the defender of free will is that if human action is subject to a universal law of causation, there will be for any action a set of sufficient conditions which can be traced back to factors outside the control of the agent. | |
| From: Philippa Foot (Free Will as Involving Determinism [1957], p.63) | |
| A reaction: She draws on Russell for this, but neither of them mention whether the causation is physical. Free will seems to imply non-physical causation. |
| 6951 | Ordinary rationality is conservative, starting from where your beliefs currently are [Harman] |
| Full Idea: Ordinary rationality is generally conservative, in the sense that you start from where you are, with your present beliefs and intentions. | |
| From: Gilbert Harman (Rationality [1995], 1.3) | |
| A reaction: This stands opposed to the Cartesian or philosophers' rationality, which requires that (where possible) everything be proved from scratch. Harman seems right, that the normal onus of proof is on changing beliefs, rather proving you should retain them. |
| 22372 | Not all actions need motives, but it is irrational to perform troublesome actions with no motive [Foot] |
| Full Idea: We do not expect that everything a rational man does should be done with a motive, ...but we do expect a man to have a motive for many things that he does, and would count anyone who constantly performed troublesome actions without a motive as irrational. | |
| From: Philippa Foot (Free Will as Involving Determinism [1957], p.66) | |
| A reaction: Interestng, because the assessment of whether someone is 'rational' therefore needs a criterion for when a motive seems required and when not. 'Significant' actions need a motive? |
| 22373 | People can act out of vanity without being vain, or even vain about this kind of thing [Foot] |
| Full Idea: It makes sense to say that a man acts out of vanity on a particular occasion although he is not in general vain, or even vain about this kind of thing. | |
| From: Philippa Foot (Free Will as Involving Determinism [1957], p.69) | |
| A reaction: Aristotle tells us that virtues and vices are habits, and also have an intellectual component, implying that the person believes in that sort of behaviour. Anyone can have 'a little moment of vanity'. |