▁ ▁Un il ine ar ▁theory ▁ ▁In ▁the ▁ 1 9 th ▁century ▁cultural ▁evolution ▁was ▁thought ▁to ▁follow ▁a ▁un il ine al ▁pattern ▁where by ▁all ▁cult ures ▁progress ively ▁develop ▁over ▁time . ▁The ▁underlying ▁assumption ▁was ▁that ▁Cultural ▁E volution ▁itself ▁led ▁to ▁the ▁growth ▁and ▁development ▁of ▁civil ization . ▁ ▁Thomas ▁Hob bes ▁in ▁the ▁ 1 7 th ▁Century ▁declared ▁ind igen ous ▁culture ▁to ▁have ▁" no ▁arts , ▁no ▁letters , ▁no ▁society " ▁and ▁he ▁described ▁facing ▁life ▁as ▁" sol it ary , ▁poor , ▁nast y , ▁brut ish , ▁and ▁short ." ▁He , ▁like ▁other ▁sch ol ars ▁of ▁his ▁time , ▁reason ed ▁that ▁everything ▁positive ▁and ▁este emed ▁resulted ▁from ▁the ▁slow ▁development ▁away ▁from ▁this ▁poor ▁low ly ▁state ▁of ▁being . ▁ ▁Under ▁the ▁theory ▁of ▁un il ine ar ▁Cultural ▁E volution , ▁all ▁soci eties ▁and ▁cult ures ▁develop ▁on ▁the ▁same ▁path . ▁The ▁first ▁to ▁present ▁a ▁general ▁un il ine al ▁theory ▁was ▁Herbert ▁Sp encer . ▁Sp encer ▁suggested ▁that ▁humans ▁develop ▁into ▁more ▁complex ▁be ings ▁as ▁culture ▁progress es , ▁where ▁people ▁originally ▁lived ▁in ▁" und iffer enti ated ▁h ord es " ▁culture ▁progress es ▁and ▁develop s ▁to ▁the ▁point ▁where ▁civil ization ▁develop s ▁hier arch ies . ▁The ▁concept ▁behind ▁un il ine ar ▁theory ▁is ▁that ▁the ▁steady ▁accum ulation ▁of ▁knowledge ▁and ▁culture ▁leads ▁to ▁the ▁separation ▁of ▁the