Fong and Nisbett (1991) claimed that human problem solvers use abstract principles to accomplish transfer to novel problems, based on findings that subjects were able to apply the law of large numbers to problems from a different domain from that in Ahich they had been trained. However, the abstract-rules position cannot account for results from other studies of analogical transfer that indicate that the content or domain ot a problem is important both for retrieving previously learned analogues (e.g., Holyoak & Koh, 1987; Keane, 1985, 1987; Ross, 1989) and for mapping base analogues onto target problems (Ross, 1989). It also cannot account for Fong and Nisbett's own findings that different-domain but not same-domain transfer was impaired after a 2-week delay. It is proposed that the content of problems is more important in problem solving than supposed by Fong and Nisbett (1991).