 Despite these worries, the conceptualist might be encouraged by the example of singular propositions.  Hasn’t the truth in vs. truth at distinction been useful in dealing with the modality of singular propositions?  For example, consider any singular proposition about Socrates, e.g., the proposition that Socrates was a philosopher. Such propositions, plausibly, depend for their existence on the object they are directly about.  One might therefore think that no singular proposition about Socrates could exist unless Socrates existed. Consider, then, the proposition that Socrates does not exist.  It is clearly contingent that Socrates exists; things could have been otherwise.  But then the proposition that Socrates does not exist would appear to be possible without being possibly true.  Unlike the examples from Pollock and Buridan, however, we cannot understand such possibility without possible truth in terms of expressing a possibly true proposition while not being possibly true itself.  Propositions do not express propositions, of course, and so we cannot understand their possibility without possible truth in this way (Plantinga 1981). What is it, then, for such a singular proposition to be possible but not possibly true?  Answering this question was one of the key motivations in the development of the distinction between truth in and truth at a world.  But while Adams and others attempted to do this by thinking of truth at a world as determined by what is true in that world together with a certain set of facts about the actual world, the conceptualist hopes to kick aside the ladder of truth in a world altogether.  Whether this hope is reasonable or not is an important issue in contemporary work on propositions. (Key recent discussions include King 2007, Soames 2010, and Merricks 2015).