Ideas from 'Defeasibility Theory' by Thomas Grundmann [2011], by Theme Structure

[found in 'Routledge Companion to Epistemology' (ed/tr Bernecker,S/Pritchard,D) [Routledge 2014,978-0-415-72269-8]].

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11. Knowledge Aims / B. Certain Knowledge / 3. Fallibilism
Indefeasibility does not imply infallibility
                        Full Idea: Infallibility does not follow from indefeasibility.
                        From: Thomas Grundmann (Defeasibility Theory [2011], 'Significance')
                        A reaction: If very little evidence exists then this could clearly be the case. It is especially true of historical and archaeological evidence.
13. Knowledge Criteria / A. Justification Problems / 1. Justification / c. Defeasibility
Defeasibility theory needs to exclude defeaters which are true but misleading
                        Full Idea: Advocates of the defeasibility theory have tried to exclude true pieces of information that are misleading defeaters.
                        From: Thomas Grundmann (Defeasibility Theory [2011], 'What')
                        A reaction: He gives as an example the genuine news of a claim that the suspect has a twin.
Can a defeater itself be defeated?
                        Full Idea: Can the original justification of a belief be regained through a successful defeat of a defeater?
                        From: Thomas Grundmann (Defeasibility Theory [2011], 'Defeater-Defs')
                        A reaction: [Jäger 2005 addresses this] I would have thought the answer is yes. I aspire to coherent justifications, so I don't see justifications as a chain of defeat and counter-defeat, but as collective groups of support and challenge.
Simple reliabilism can't cope with defeaters of reliably produced beliefs
                        Full Idea: An unmodified reliabilism does not accommodate defeaters, and surely there can be defeaters against reliably produced beliefs?
                        From: Thomas Grundmann (Defeasibility Theory [2011], 'Defeaters')
                        A reaction: [He cites Bonjour 1980] Reliabilism has plenty of problems anyway, since a generally reliable process can obviously occasionally produce a bad result. 20:20 vision is not perfect vision. Internalist seem to like defeaters.
You can 'rebut' previous beliefs, 'undercut' the power of evidence, or 'reason-defeat' the truth
                        Full Idea: There are 'rebutting' defeaters against the truth of a previously justified belief, 'undercutting' defeaters against the power of the evidence, and 'reason-defeating' defeaters against the truth of the reason for the belief.
                        From: Thomas Grundmann (Defeasibility Theory [2011], 'How')
                        A reaction: That is (I think) that you can defeat the background, the likelihood, or the truth. He cites Pollock 1986, and implies that these are standard distinctions about defeaters.
Knowledge requires that there are no facts which would defeat its justification
                        Full Idea: The 'defeasibility theory' of knowledge claims that knowledge is only present if there are no facts that - if they were known - would be genuine defeaters of the relevant justification.
                        From: Thomas Grundmann (Defeasibility Theory [2011], 'What')
                        A reaction: Something not right here. A genuine defeater would ensure the proposition was false, so it would simply fail the truth test. So we need a 'defeater' for a truth, which must therefore by definition be misleading. Many qualifications have to be invoked.
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / b. Basic beliefs
'Moderate' foundationalism has basic justification which is defeasible
                        Full Idea: Theories that combine basic justification with the defeasibility of this justification are referred to as 'moderate' foundationalism.
                        From: Thomas Grundmann (Defeasibility Theory [2011], 'Significance')
                        A reaction: I could be more sympathetic to this sort of foundationalism. But it begins to sound more like Neurath's boat (see Quine) than like Descartes' metaphor of building foundations.