 Note: these thought-experiments can only be performed when \(\mathbf{p}(A)\) is not 0. On this approach, indicative conditionals only have a role when the thinker takes \(A\) to be an epistemic possibility. If you take yourself to know for sure that Ann is in Paris, you don’t go in for “If Ann is not in Paris …” thoughts (though of course you can think “If Ann had not been in Paris …”). In conversation, you can pretend to take something as an epistemic possibility, temporarily, to comply with the epistemic state of the hearer. When playing the sceptic, there are not many limits on what you can, at a pinch, take as an epistemic possibility – as not already ruled out. But there are some limits, as Descartes found. Is there a conditional thought that begins “If I don’t exist now …”?