Animalism and Dicephalus: The Psychological Disunity Solution

According to animalism, each of us is essentially a human organism. As such, the number of persons corresponds to the number of organisms. Dicephalic conjoined twins, such as the Hensel twins, challenge this view, as they appear to be two persons but only one organism. This is the dicephalus objection to animalism. In this paper, we address this problem. First, we introduce the Hensel case and outline the dicephalus objection (§1). We then discuss two prominent animalist responses: the indeterminacy solution, which holds that the Hensel twins are a borderline case of human animal (§2), and the overlap solution, which posits two overlapping organisms in the Hensel case (§3). We reject both views, arguing instead that there is exactly one organism and a single person with two functional brains (or psychological centers) and a highly disunified psychology. This is the psychological disunity solution (§4). We conclude by addressing potential objections to our view (§5).