ABSTRACT
It is obvious that humans are intelligent creatures. We display capacities to learn and to know that surpass all other species—at least in many domains. Furthermore, it is clear that intelligence is somehow connected to our genetic endowment because everything we do is at least permitted by our genes. What is less clear is whether intelligence considered as a general species trait is a biological adaptation in the strict sense. The strict sense we have in mind says that for some trait T (intelligence in the present case) and for some species S, T is an adaptation if and only if T was selected and maintained in S because T led (and possibly still does lead) to reproductive success and stability for S in a particular environment. This requires that for T to be a biological adaptation it led—or better, contributed—to population growth and stability at a level supportable by the ecological niche S occupies. Furthermore, to provide a case that some trait T is an adaptation, there must be reason to believe that T is heritable, that offspring are more likely to have trait T, if their parents had it.
