Wed Mar 14, 2018
234 Moses, 6–7:30 PM
|Working Group in the History and Philosophy of Logic, Mathematics, and Science
Alan Hajek (ANU)
Most Counterfactuals Are Still False
I have long argued for a kind of ‘counterfactual scepticism’: most counterfactuals are false. I maintain that the indeterminism and indeterminacy associated with most counterfactuals entail their falsehood. For example, I claim that these counterfactuals are both false:
(Indeterminism) If the chancy coin were tossed, it would land heads.
(Indeterminacy) If I had a son, he would have an even number of hairs on his head at his birth.
And I argue that most counterfactuals are relevantly similar to one or both of these, as far as their truth-values go. I also have arguments from the incompatibility of ‘would’ and ‘might not’ counterfactuals, and from so-called ‘reverse-Sobel sequences’.
However, counterfactual reasoning seems to play an important role in science, and ordinary speakers judge many counterfactuals that they utter to be true. A number of philosophers have defended such judgments against counterfactual scepticism. David Lewis and others appeal to ‘quasi-miracles’; Robbie Williams to ‘typicality’; John Hawthorne and H. Orri Stefánsson to ‘counterfacts’, primitive counterfactual facts; Moritz Schulz to an arbitrary-selection semantics; Jonathan Bennett and Hannes Leitgeb to high conditional probabilities; Karen Lewis to contextually-sensitive ‘relevance’.
I argue against each of these proposals. A recurring theme is that they fail to respect certain valid inference patterns. I conclude: most counterfactuals are still false.