We consider three perspectives in determing the number of persons involved in the so called "Hensel twins", a case of adult conjoined twins: 1. the materialistic perspective establishes the equivalence between the number of brains and the number of persons involved. A body having two brains is indeed two distinct persons; 2. according to the linguistic turn, dialogue is what establishes the subjects involved in the so called adult conjoined twins. In this perspective, the Hensel twins are (again, but for different reasons) two dinstinct persons; 3. considering the somatocentric turn, the human being is characterized by his/her body. Being the world experienced through the body, the "Hensel twins" are just one single person. In conclusion, none of these perspectives, once considered detached from the others, fit to determine the number of "Hensel twins": the Hensel twins are two persons sharing the very same body.