The relationship between propositions and sentences is a little hard to pin down since a sentence will always advance or express one or more propositions and a proposition will always be in the form of a sentence. The key here is to think of a sentence as being a visible piece of writing and the propositions its advances as assumptions and ideas not necessarily written out. The easiest way of thinking about this relationship is to say that a written sentence usually rests on or contains or combines a number of underlying propositions, most of which the sentence simply assumes and which would be too basic or simple-sounding to actually write out. I like to think of the written sentence as the part of the iceberg you see above water, while many of its underlying propositions remain out of sight underwater. Put another way, propositions are the atoms from which the molecule of the sentence is constructed.Landon goes on to illustrate this idea with a very simple sentence: "I like hamburgers." Sounds agonizingly straightforward, doesn't it? But Landon notes that it presupposes a number of things, such as 1) the speaker exists; 2) there is a food called a hamburger; 3) that food is capable of causing enjoyment, at least in some people; and 4) that someone might actually care about learning that fact. Now if you aren't already muzzy with boredom, you might be wondering, "Why does this matter when it comes to genre fiction anyway?" Well, the idea that propositions are the building blocks of sentences (which are the building blocks of stories) has huge thematic implications. If you automatically infuse your beliefs into every clause, then you can't help slinging themes every which way no matter what you write.
Let's pluck a story from the headlines by way of example: A government strives to remedy an environmental disaster caused by a corporation. Straightforward enough, but the way in which you tell it leads to very different thematic emphases. "The bags beneath the CEO's eyes grew deeper and darker by the day as he struggled to facilitate a solution for a problem baffling the world's best scientists," lands much differently than, "'Of course I'm working on it!' Tony snapped. 'I'd like the whole thing to be fixed as much as you, and I'd like my life back while we're at it!'" Ditto for an administration clean-up effort that's either "tenacious," "tentative" or "torpid." See the propositions behind those choices? They certainly reveal different sorts of thinking about the same situation. Landon's thesis that our beliefs choose our words is a call for more careful consideration, a reminder that every idea has impact, both on our works and those who read them.
(Picture: CC 2007 by love not fear)