  One may also worry that, throughout the PAO, Vaihinger has reverted to a crudely psychologistic version of Kantianism that both he and Cohen had earlier rejected. On this score, Vaihinger is more easily defended. Though his fictionalism draws on certain biological and psychological theories, his main concern is still epistemological: “Apart from the general warning not to confuse fictions with reality, we may also call attention to the fact that every fiction must be able to justify itself, i.e., must justify itself by what it accomplishes for the progress of science” (PAO 79). There would arguably be a confusion if Vaihinger held that the fact that certain concepts (or dispositions to form them) are psychologically innate justifies us in believing that there exist objects exemplifying them. But that is precisely the view he wishes to reject. The appeal to the theory of natural selection is intended to suggest a pragmatic, rather than evidential, justification for the use of those concepts. In this sense, Vaihinger sees himself as drawing on Kant’s method of justifying the concepts of God, freedom, and immortality on practical grounds, but extending it beyond the domain of moral philosophy.