 We also agree that the inferences drawn in thought experimenting are highly problematic if the hypothetical scenario “is inadequately described” (Wilkes 1988, p. 8). But Wilkes seems to think that the lack of description is unavoidable, which supposedly amounts to a reason against philosophical thought experiments on personal identity because persons are not natural kinds. This makes it impossible to fill in necessary information to make the thought experiment work given its unavoidable underdetermination. Wilkes thinks that “whenever we are examining the ranges of concepts that do not pick on natural kinds, the problem of deciding what is or what is not ‘relevant’ to the success of the thought experiment is yet more problematic than the same question as it arises in science; and, unlike the scientific problem, it may not even have an answer in principle” (Wilkes 1988, p. 15). She adds that scientific laws — especially those describing biological kinds like human beings — “are not disjoint and independent, detachable from one another […]. They are interrelated, to varying degrees of course” (Wilkes 1988, p. 29). This implies, for example, that “a full psychophysiological account of the processes of human perception must at some stage link up with part at least of linguistic ability; for we typically see things under a certain description, and that description may be a very sophisticated one” (Wilkes 1988, p. 29). These considerations have her rule out experiments that challenge the human monopoly of personhood. No thought experiment, claims Wilkes, is well conceived if it involves non-human animals or computers as persons. But also those thought experiments can be ruled out which involve the “fission or fusion of humans” because it is not theoretically possible. “The total impact of the sum of laws that group us together as human beings (a natural kind category) precludes our splitting into two […] or fusing with someone else” (Wilkes 1988, p. 36).