Combining Texts

Ideas for 'On 'Generation and Corruption'', 'Change in View: Principles of Reasoning' and 'The Nature of Mathematics'

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3 ideas

10. Modality / B. Possibility / 1. Possibility
Some logical possibility concerns single propositions, but there is also compatibility between propositions [Peirce]
     Full Idea: Many say everything is logically possible which involves no contradiction. In this sense two contradictory propositions may be severally possible. In the substantive sense, the contradictory of a possible proposition is impossible (if we were omniscient).
     From: Charles Sanders Peirce (The Nature of Mathematics [1898], III)
10. Modality / B. Possibility / 6. Probability
The Gambler's Fallacy (ten blacks, so red is due) overemphasises the early part of a sequence [Harman]
     Full Idea: The Gambler's Fallacy says if black has come up ten times in a row, red must be highly probable next time. It overlooks how the impact of an initial run of one color can become more and more insignificant as the sequence gets longer.
     From: Gilbert Harman (Change in View: Principles of Reasoning [1986], 1)
     A reaction: At what point do you decide that the roulette wheel is fixed, rather than that you have fallen for the Gambler's Fallacy? Interestingly, standard induction points to the opposite conclusion. But then you have prior knowledge of the wheel.
High probability premises need not imply high probability conclusions [Harman]
     Full Idea: Propositions that are individually highly probable can have an immediate implication that is not. The fact that one can assign a high probability to P and also to 'if P then Q' is not sufficient reason to assign high probability to Q.
     From: Gilbert Harman (Change in View: Principles of Reasoning [1986], 3)
     A reaction: He cites Kyburg's Lottery Paradox. It is probable that there is a winning ticket, and that this ticket is not it. Thus it is NOT probable that I will win.