▁similar ▁view ▁( with ▁which ▁they ▁disag ree ): ▁ ▁Because ▁of ▁the ▁philosoph ical ▁questions ▁of ▁conscious ness ▁and ▁mind ▁that ▁are ▁involved , ▁many ▁scient ists ▁have ▁stayed ▁away ▁from ▁exam ining ▁animal ▁and ▁human ▁em otion , ▁and ▁have ▁instead ▁studied ▁meas urable ▁brain ▁functions ▁through ▁neu ros cience . ▁ ▁Compar ative ▁approach ▁In ▁ 1 9 0 3 , ▁C . ▁Lloyd ▁Morgan ▁published ▁Morgan ' s ▁Can on , ▁a ▁special ised ▁form ▁of ▁Occ am ' s ▁raz or ▁used ▁in ▁eth ology , ▁in ▁which ▁he ▁stated : ▁ ▁Dar win ' s ▁approach ▁Charles ▁Dar win ▁initially ▁planned ▁to ▁include ▁a ▁chapter ▁on ▁em otion ▁in ▁The ▁Des cent ▁of ▁Man ▁but ▁as ▁his ▁ideas ▁progress ed ▁they ▁expanded ▁into ▁a ▁book , ▁The ▁Expression ▁of ▁the ▁Em ot ions ▁in ▁Man ▁and ▁Anim als . ▁Dar win ▁proposed ▁that ▁emot ions ▁are ▁adapt ive ▁and ▁serve ▁a ▁communic ative ▁and ▁motiv ational ▁function , ▁and ▁he ▁stated ▁three ▁principles ▁that ▁are ▁useful ▁in ▁understanding ▁emot ional ▁expression : ▁First , ▁The ▁Princi ple ▁of ▁Service able ▁Hab its ▁takes ▁a ▁L amar ck ian ▁st ance ▁by ▁suggesting ▁that ▁emot ional ▁expressions ▁that ▁are ▁useful ▁will ▁be ▁passed ▁on ▁to ▁the ▁off spring . ▁Second , ▁The ▁Princi ple ▁of ▁Ant ith esis ▁suggests ▁that ▁some ▁expressions ▁exist ▁merely ▁because ▁they ▁opp ose ▁an ▁expression ▁that ▁is ▁useful . ▁Third , ▁The ▁Princi ple ▁of ▁the ▁Direct ▁Action ▁of ▁the ▁Ex c ited