 One difficulty for the problem-solving account is to find a proper framework for identifying and counting problems (Rescher 1984; Kleiner 1993). When Newton’s mechanics is applied to determine the orbit of the planet Mars, this can be counted as one problem. But, given an initial position of Mars, the same theory entails a solution to an infinite number of questions concerning the position of Mars at time \(t\). Perhaps the most important philosophical issue is whether one may consistently hold that the notion of problem-solving may be entirely divorced from truth and falsity: the realist may admit that science is a problem-solving activity, if this means the attempt to find true solutions to predictive and explanatory questions (Popper, 1972; Niiniluoto 1984). Bird’s (2007) main criticism against the “functional account” of Kuhn and Laudan is its consequence that the cumulation of false solutions from an entirely false theory counts as scientific progress (e.g. Oresme in the fourteenth century believed that hot goat’s blood could split diamonds).