Joyce (1999: 102–4) and Jeffrey (1984: 138–41) both make similar claims. A particularly detailed argument along these lines for comparative belief can be found in Hawthorne (2009). Indeed, this idea has a long and distinguished history that goes back at least as far as B.O. Koopman (1940). I.J Good (1962), Terrence Fine (1973) and Patrick Suppes (1974) all discussed ideas along these lines. Seidenfeld, Schervish, and Kadane (1995) give a representation theorem for preference that don’t satisfy completeness. (See Evren and Ok 2011; Pedersen 2014; and Chu and Halpern 2008, 2004; for very general representation theorems).