Thought about scientific models and modelling practices in the sciences has a long tradition. It has recently been argued that this practice of science also exists in metaphysics. In this paper, I show that this view has two significant historical forerunners: Hans Vaihinger and Salomon Maimon. Vaihinger provided what is today often seen as the starting point of the contemporary debate on scientific models as fictions. He argued that fictions can be equally useful in the sciences as in metaphysics. However, (...) Vaihinger‘s position is problematic. Firstly, he mainly credits Kant for providing the first comprehensive account of the method of fictions in the sciences. I will argue that contrary to his claims, it was Maimon – whom Vaihinger only mentions in passing – who first adapted Kant‘s doctrine of ideas to serve the purposes of a fictionalist agenda. I will show that Maimon‘s account of scientific fictions already contains many of the features which Vaihinger claims to have discovered himself. Secondly, Vaihinger’s failure to distinguish between the use of fictions in the sciences and metaphysics creates a problem for some types of metaphysical fictions. I show that Maimon‘s account of metaphysical fictions identifies and avoids this problem. (shrink)