Wemaybeginbyaskingwhether,accordingtoAquinas,the
Christianprohibitiononkillingappliestocreaturesotherthan
humans, and if not, why not. Aquinas answers:
Thereisnosininusingathingforthepurposeforwhichitis.
Nowtheorderofthingsissuchthattheimperfectareforthe
perfect....Things,likeplantswhichmerelyhavelife,areall
alikeforanimals,andallanimalsareforman.Whereforeitis
not unlawful if men use plants for the good of animals,
andanimals forthegoodofman,asthePhilosopherstates
(PoliticsI, 3).
Nowthemostnecessaryusewouldseemtoconsistinthefact
thatanimalsuseplants,andmenuseanimals,forfood,and
this cannot be done unless these be deprived of life,
whereforeitislawfulbothtotakelifefromplantsfortheuse
ofanimals,andfromanimalsfortheuseofmen.Infactthisis
inkeepingwiththecommandmentofGodhimself(Genesisi,
29, 30 andGenesisix, 3).^11
ForAquinasthepointisnotthatkillingforfoodisinitself
necessaryand therefore justifiable (sinceAquinas knew of
sectsliketheManicheesinwhichthekillingofanimalswas
forbidden,hecouldnothavebeenentirelyignorantofthefact
thathumanbeingscanlivewithoutkilling animals,but we
shall overlook this for the moment); itis only the “more
perfect”whoareentitledtokillforthisreason.Animalsthat
kill human beings for food are in a quite different category:
Savageryand brutalitytaketheirnamesfrom alikenessto
wildbeasts.Foranimalsofthiskindattackmanthattheymay
feedon hisbody, and not forsome motive of justice, the
consideration of which belongs to reason alone.^12