 Counterfactual thinking. Richard Kilvington comments on obligations in his Sophismata (S47; Kretzmann &amp; Kretzmann 1990a; 1990b). In his view, it should not be possible to force the respondent to grant any falsities whatsoever, and the order in which propositions are put forward ought not to have an effect on their evaluation. As Kilvington sees it, the respondent should grant only those falsities which would be true if the positum were true. Kilvington gives the following example (S47, (q); Kretzmann &amp; Kretzmann 1990b, 127–8):