Allan has a post about disagreement, which happens to correspond to a disagreement that occurred between Ben and me at the GCB last night. I say, we can disagree about things that are not propositions; Ben disagrees. My example: suppose Ben and I are looking for a place to live, and he says, "Let's live on Wickenden." I say, "No, let's live on Hope". We disagree, even though there's no proposition he's assenting to that I think is false, or vice versa.