, ▁into ▁an ▁imper fect ▁world , ▁has ▁been ▁the ▁major ▁influence . ▁Cart esian ▁dual ism , ▁from ▁the ▁sevent e enth ▁century ▁on , ▁ ▁further ▁rein for ced ▁this ▁dual istic ▁thinking ▁about ▁nature . ▁ ▁With ▁this ▁dual ism ▁goes ▁value ▁jud g ement ▁as ▁to ▁the ▁superior ity ▁of ▁the ▁natural ▁over ▁the ▁artificial . ▁Modern ▁science , ▁however , ▁is ▁moving ▁towards ▁a ▁hol istic ▁view ▁of ▁nature . ▁ ▁America ▁What ▁is ▁meant ▁by ▁natural , ▁within ▁the ▁American ▁conservation ▁movement , ▁has ▁been ▁changing ▁over ▁the ▁last ▁century ▁and ▁a ▁half . ▁ ▁In ▁the ▁mid - n in ete enth ▁century ▁American ▁began ▁to ▁realize ▁that ▁the ▁land ▁was ▁becoming ▁more ▁and ▁more ▁domestic ated ▁and ▁wild life ▁was ▁disappear ing . ▁This ▁led ▁to ▁the ▁creation ▁of ▁American ▁National ▁Park s ▁and ▁other ▁conservation ▁sites . ▁Initial ly ▁it ▁was ▁believed ▁that ▁all ▁that ▁was ▁needed ▁to ▁do ▁was ▁to ▁separate ▁what ▁was ▁seen ▁as ▁natural ▁landscape ▁and ▁" av oid ▁dist urban ces ▁such ▁as ▁logging , ▁gra zing , ▁fire ▁and ▁insect ▁out break s ." ▁This , ▁and ▁subsequent ▁environmental ▁policy , ▁until ▁recently , ▁was ▁influenced ▁by ▁ideas ▁of ▁the ▁w ilder ness . ▁However , ▁this ▁policy ▁was ▁not ▁consist ently ▁applied , ▁and ▁in ▁Y ellow stone ▁Park , ▁to ▁take ▁one ▁example , ▁the ▁existing ▁e col ogy ▁was ▁alter ed , ▁first ly ▁by ▁the ▁ex clusion ▁of ▁Native ▁Americans ▁and ▁later ▁with ▁the ▁virtual