Animalscanfeelpain.Aswesawearlier,therecanbe no
moraljustification forregarding thepain(orpleasure) that
animalsfeelaslessimportantthanthesameamountofpain
(orpleasure)feltbyhumans.Butwhatpracticalconsequences
followfromthisconclusion?TopreventmisunderstandingI
shall spell out what I mean a little more fully.
IfIgiveahorseahard slapacrossitsrumpwithmyopen
hand,thehorsemaystart,butitpresumablyfeelslittlepain.
Itsskinisthickenoughtoprotectitagainstamereslap.IfI
slapababyinthesameway,however,thebabywillcryand
presumablyfeelpain,foritsskinismoresensitive.Soitis
worse to slap a baby than a horse, if both slaps are
administeredwithequalforce.Buttheremustbesomekind
ofblow—Idon’tknowexactlywhatitwouldbe,butperhaps
a blowwith a heavystick—thatwould causethehorse as
muchpainaswecauseababybyslappingitwithourhand.
ThatiswhatImeanby“thesameamountofpain,”andifwe
consideritwrongtoinflictthatmuchpainonababyforno
goodreasonthenwemust,unlesswearespeciesists,consider
itequallywrongtoinflictthesameamountofpainonahorse
for no good reason.
Otherdifferences betweenhumansand animalscauseother
complications. Normal adult human beings have mental
capacities that will,in certain circumstances, leadthem to
suffermorethananimalswouldinthesamecircumstances.If,
for instance, we decided to perform extremely painful or
lethal scientific experiments on normal adult humans,
kidnapped at random from public parks for this purpose,
adultswhoenjoystrollinginparkswouldbecomefearfulthat
theywould be kidnapped. Theresultant terrorwould be a
form ofsuffering additionalto thepainofthe experiment.