▁cult ures . ▁The ▁anth rop ologist ▁fills ▁in ▁with ▁compar isons ▁to ▁other ▁cult ures ▁and ▁is ▁forced ▁to ▁rely ▁on ▁theories ▁that ▁have ▁no ▁evident ial ▁basis , ▁the ▁old ▁notion ▁of ▁universal ▁stages ▁of ▁development ▁or ▁the ▁claim ▁that ▁cultural ▁res embl ances ▁are ▁based ▁on ▁some ▁un recogn ized ▁past ▁contact ▁between ▁groups . ▁Bo as ▁came ▁to ▁believe ▁that ▁no ▁overall ▁pattern ▁in ▁social ▁development ▁could ▁be ▁proven ; ▁for ▁him , ▁there ▁was ▁no ▁single ▁history , ▁only ▁histor ies . ▁ ▁There ▁are ▁three ▁broad ▁choices ▁involved ▁in ▁the ▁diver gence ▁of ▁these ▁schools – each ▁had ▁to ▁decide ▁what ▁kind ▁of ▁evidence ▁to ▁use ; ▁whether ▁to ▁emphas ize ▁the ▁particular s ▁of ▁a ▁single ▁culture ▁or ▁look ▁for ▁patterns ▁underlying ▁all ▁soci eties ; ▁and ▁what ▁the ▁source ▁of ▁any ▁underlying ▁patterns ▁might ▁be , ▁the ▁definition ▁of ▁a ▁common ▁human ity . ▁Social ▁scient ists ▁in ▁all ▁trad itions ▁re lied ▁on ▁cross - c ult ural ▁studies . ▁It ▁was ▁always ▁necessary ▁to ▁supp lement ▁information ▁about ▁a ▁society ▁with ▁information ▁about ▁others . ▁So ▁some ▁idea ▁of ▁a ▁common ▁human ▁nature ▁was ▁implicit ▁in ▁each ▁approach . ▁The ▁critical ▁distinction , ▁then , ▁remained : ▁does ▁a ▁social ▁fact ▁exist ▁because ▁it ▁is ▁functional ▁for ▁the ▁social ▁order , ▁or ▁because ▁it ▁is ▁functional ▁for ▁the ▁person ? ▁Do ▁uniform ities ▁across ▁cult ures ▁occur ▁because ▁of ▁organiz ational ▁needs ▁that ▁must ▁be ▁met ▁everywhere , ▁or ▁because ▁of ▁the ▁uniform