Under certain circumstances, a deductive or ‘theoretical’ mode of reasoning is revealed among young children, as well as among illiterate adults. In four experiments we asked whether 4-, 5- and 6-year-old children can extend their deductive abilities to syllogisms whose content runs counter to their practical world knowledge. In Experiment 1, premises were presented within the context of play, using suitable toys and props, or in the ordinary verbal mode. Syllogisms with known, unknown as well as contrary facts were included. Children's performance following presentation in the verbal mode was less accurate than with presentation in the context of play, particularly when syllogisms with contrary facts were included in the premises. Experiments 2, 3 and 4 showed that it is the make-believe context of play rather than the visible presence of toys during play that facilitates children's reasoning when the premises of the problems run counter to their experience.