I’ve gotten a couple of questions on question #7 of the practice final. What it asks you to do is translate the following into English:<\/p>\n
λp<\/em> [ ∃x<\/em> [ p<\/em> = λw [ person(x<\/em>) ∧ poisoned-the-vodka(x<\/em>, w<\/em>) ]]]<\/p>\n There is a sense in which this question isn’t really “fair” in that we’ve never really talked about these things in these terms.<\/p>\n But, here’s where that was going: p<\/em> here is supposed to a proposition. A proposition is something that is true in some worlds, false in others. Although we haven’t been doing this, we can make the world dependence explicit by saying that a proposition is a function from possible worlds to truth values. So, e.g., John weeps<\/em> is a function that, given a world w<\/em> is either true (if John weeps in w<\/em>) or false (otherwise).<\/p>\n That is: λw<\/em> [ John weeps in w<\/em> ]<\/p>\n So, now, suppose that you have the proposition λw<\/em> [ person(w<\/em>) ∧ poisoned-the-vodka(x<\/em>, w<\/em>) ] for some x<\/em>. That will be one of the possible answers to the question Who poisoned the vodka?<\/em>.<\/p>\n The idea in the formula in question 7 is that a proposition is in the set of propositions the formula is describing if there is an x<\/em> such that the proposition is x poisoned the vodka<\/em>.<\/p>\n I’ll try to stick to things we actually covered, on tomorrow’s test…<\/p>\n","protected":false},"excerpt":{"rendered":" I’ve gotten a couple of questions on question #7 of the practice final. What it asks you to do is translate the following into English: λp [ ∃x [ p = λw [ person(x) ∧ poisoned-the-vodka(x, w) ]]] There is a sense in which this question isn’t really “fair” in that we’ve never really talked …<\/p>\n