more from Gilbert Harman

Single Idea 19310

[catalogued under 10. Modality / B. Possibility / 6. Probability]

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.

Gist of Idea

High probability premises need not imply high probability conclusions


Gilbert Harman (Change in View: Principles of Reasoning [1986], 3)

Book Reference

Harman,Gilbert: 'Change in View: Principles of Reasoning' [MIP 1986], p.23

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.

Related Idea

Idea 6368 If my ticket won't win the lottery (and it won't), no other tickets will either [Kyburg, by Pollock/Cruz]