A definite answer to the latter question ought not to be expected, seeing that no one can solve the simpler problem, why, of two races of savages, one has risen higher in the scale of civilisation than the other; and this apparently implies increased brain power.
Ez litzateke espero behar erabateko erantzunik arestiko galderari, ikusirik inork ezin diola soluziorik eman honako beste arazo errazago honi ere, alegia, basa-arraza bitik bat zergatik iritsi den bestea baino gorago zibilizazio eskalan; eta honek, dirudienez, burmuin-ahal handiagoa inplikatzen du.