Full Idea
Moore's Paradox: one is strongly disposed not to believe both P and that one does not believe that P, while realising that these propositions are perfectly consistent with one another.
Gist of Idea
We strongly desire to believe what is true, even though logic does not require it
Source
Gilbert Harman (Change in View: Principles of Reasoning [1986], 2)
Book Reference
Harman,Gilbert: 'Change in View: Principles of Reasoning' [MIP 1986], p.19
A Reaction
[Where in Moore?] A very nice example of a powerful principle of reasoning which can never be captured in logic.