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Single Idea 22178

[filed under theme 14. Science / C. Induction / 6. Bayes's Theorem ]

Full Idea

If the only objective constraints concern how we should change our credences, but what our initial credences should be is entirely subjective, then individuals with very bizarre opinions about the world will count as perfectly rational.

Gist of Idea

If the rules only concern changes of belief, and not the starting point, absurd views can look ratiional

Source

Samir Okasha (Philosophy of Science: Very Short Intro (2nd ed) [2016], 2)

Book Ref

Okasha,Samir: 'Philosophy of Science: very short intro (2nd ed)' [OUP 2016], p.35

A Reaction

The important rationality has to be the assessement of a diverse batch of evidence, for which there can never be any rules or mathematics.

The 19 ideas with the same theme [equation showing probability of an inductive truth]:

14280 The probability of two events is the first probability times the second probability assuming the first [Bayes]
22656 Trying to assess probabilities by mere calculation is absurd and impossible [James]
19143 Ramsey gave axioms for an uncertain agent to decide their preferences [Ramsey, by Davidson]
19155 Instead of gambling, Jeffrey made the objects of Bayesian preference to be propositions [Jeffrey, by Davidson]
2751 Probabilities can only be assessed relative to some evidence [Dancy,J]
2798 Probability of H, given evidence E, is prob(H) x prob(E given H) / prob(E) [Horwich]
2799 Bayes' theorem explains why very surprising predictions have a higher value as evidence [Horwich]
16802 Bayes seems to rule out prior evidence, since that has a probability of one [Lipton]
16803 Bayes is too liberal, since any logical consequence of a hypothesis confirms it [Lipton]
16801 A hypothesis is confirmed if an unlikely prediction comes true [Lipton]
16837 Bayes involves 'prior' probabilities, 'likelihood', 'posterior' probability, and 'conditionalising' [Lipton]
16839 Explanation may be an important part of implementing Bayes's Theorem [Lipton]
6372 Since every tautology has a probability of 1, should we believe all tautologies? [Pollock/Cruz]
17600 Bayesian inference is forced to rely on approximations [Thagard]
14990 Bayes produces weird results if the prior probabilities are bizarre [Sider]
6798 Bayesianism claims to find rationality and truth in induction, and show how science works [Bird]
22178 If the rules only concern changes of belief, and not the starting point, absurd views can look ratiional [Okasha]
17943 Probability supports Bayesianism better as degrees of belief than as ratios of frequencies [Colyvan]
22365 The Bayesian approach is explicitly subjective about probabilities [Reiss/Sprenger]