Everyone is equally content with our present configuration of fingers. Humans are always equally content with two things of equal usefulness. The perceived usefulness of our configuration of fingers is an illusory result of our prejudices. Humans are never equally content with two things of unequal usefulness.
Biologist: Humans have five fingers because we descended from a fish with five phalanges in its fins. Despite our prejudices to the contrary, our configuration of fingers is no more or less useful than several other possible configurations, e. g. , six per hand. So, if humans had descended from a fish with six phalanges in its fins and had six fingers on each hand, then we would be just as content with that configuration.
Which one of the following, if true, most strengthens the biologist's argument?