To a large extent, the neocortex’s functioning is dedicated to solving the problem of underdetermination. Hubel and Wiesel’s discovery of simple cells in V1 made it thinkable that the brain has a hard-wired feature detection machinery for all sorts of features that are detectable in the visual field. Their discoveries made many philosophers believe that the neural code should be understood as a one-directional causal process that computes for similarities in the environment. This allows for a realist interpretation of solving the underdetermination problem as an inverse problem of perception to find what there is in the world.