  These elements (particulars and universals) define a range of combinations, some of them actualised, some not. These combinations must respect the form of states of affairs (thus Aristotle's being wise is an actualised combination, Aristotle's being a general is an unactualised combination, and wisdom's being Aristotle does not respect the form of states of affairs and so does not fall in the range of combinations defined by particulars and universals). The possible atomic states of affairs are the combinations of particulars and universals which respect the form of states of affairs. The merely possible atomic states of affairs are the recombinations of particulars and universals, i.e. those combinations which do not actually occur, like Aristotle's being a   general.[28]  Possible worlds are, for Armstrong, conjunctions of possible atomic states of affairs (1989, 47,  48).[29] 