| 10121 | Contradiction is not a sign of falsity, nor lack of contradiction a sign of truth [Pascal] |
| 2111 | Falsehood involves a contradiction, and truth is contradictory of falsehood [Leibniz] |
| 18736 | Contradiction is between two rules, not between rule and reality [Wittgenstein] |
| 23496 | Two colours in the same place is ruled out by the logical structure of colour [Wittgenstein] |
| 12194 | Contradictions include 'This is red and not coloured', as well as the formal 'B and not-B' [Rumfitt] |