I’ll be away from blogging for the weekend because I’m on a road trip – off to Cornell to do a paper, visit friends, drop into Creighton Club (not normally known as a tourist attraction) etc.

It’s bad of me to do this while I haven’t written up the last poll, but while I’m away I thought I’d leave you a little puzzle. This one is an old puzzle of Alan Gibbard’s, but I was reminded of it by Keith DeRose in his talk at MIT last Friday.

Sly Pete is gambling. It’s the last bet of the night, and Sly Pete wants to win. At the very least, he doesn’t want to lose. So he cheats. He has two spies Jack and Jill signal the contents of the other player’s hand to him. Both of them send in the signs, and both of them get the confirmation from Sly Pete of their signals. Assume the game is such that whether Sly Pete bets or not, the game is over. If he bets, the person with the better hand wins. And that, as Sly Pete now knows, although Jack and Jill do not, is not Pete. If he does not bet, no money changes hands.

After completing their mission, signalling the contents of the other player’s hand to Sly Pete, Jack and Jill report back to their paymaster. They utter the following sentences, both inspired by their knowledge that Pete knows what is in both hands, and Pete doesn’t make losing bets at the end of the night, at least when he knows he’s going to lose. (Assume the game is such that there are no ties – if someone bets they either win or lose.)

Jill: If Pete bets, he will win.
Jack: If Pete were to bet, he would win.

Pete, sometime after these reports are made, declines to bet.

Which of spies (if any) spoke truly (i.e. semantically expressed a true proposition)?

I promise I’ll write up both polls when I return. Have a fun weekend.

PS: If anyone posts an online report on the Yale philosophy of language conference, let me know. I’d like to hear what happens, and I’d like to be able to at least link to a report.