The possible, species, and the question of the autonomy of metaphysics

Metaphysics has a long tradition of being the science of the possible, which, at first glance, guarantees it a form of autonomy from the natural sciences: science says what is, while metaphysics says what could be or could have been. I'll use the example of biological species to show that, when it comes to the necessity or possibility of particular kinds of things, modal knowledge is irreducibly empirical and therefore beyond the reach of metaphysics understood as an a priori or " armchair " discipline . This is not, however, a replay of the old cliché of the abuses of metaphysics-denounced-by-science. My aim here is to highlight the tensions, but also the cooperation, between two kinds of metaphysics that are equally legitimate in their respective domains: the metaphysics of science, i.e., emanating from science, and the metaphysics armchair.