▁ep ist em ology , ▁eth ics ▁and ▁moral ▁philosophy , ▁political ▁philosophy , ▁and ▁the ▁history ▁of ▁ 1 9 th ▁and ▁ 2 0 th ▁century ▁philosophy . ▁He ▁is ▁best ▁known ▁for ▁his ▁work ▁on ▁John ▁Stuart ▁Mill ▁and ▁his ▁study ▁of ▁norm ativity , ▁The ▁Domain ▁of ▁Re asons . ▁ ▁Career ▁Sk or ups ki ▁studied ▁philosophy ▁and ▁econom ics ▁at ▁Christ ' s ▁College , ▁Cambridge , ▁from ▁which ▁he ▁received ▁both ▁an ▁MA ▁and ▁a ▁Ph D . ▁▁ 1 9 7 1 – 7 2 ▁Vis iting ▁L ect urer ▁at ▁the ▁University ▁of ▁If e , ▁Niger ia ▁( now ▁Ob af emi ▁Aw ol owo ▁University ) ▁ 1 9 7 4 ▁Vis iting ▁Professor ▁at ▁the ▁K athol ie ke ▁Univers iteit ▁Le u ven ▁( the ▁University ▁of ▁Lou v ain ), ▁Belg ium ▁ 1 9 7 4 – 7 6 ▁Research ▁Fellow ▁at ▁Sw anse a ▁University ▁( Univers ity ▁of ▁Wales , ▁Sw anse a ) ▁ 1 9 7 6 – 8 4 ▁L ect urer ▁at ▁the ▁University ▁of ▁Glasgow ▁ 1 9 8 4 – 9 0 ▁Professor ▁of ▁Philosoph y ▁at ▁the ▁University ▁of ▁She ff ield ▁ 1 9 9 0 – present ▁Professor ▁of ▁Mor al ▁Philosoph y ▁at ▁the ▁University ▁of ▁St ▁Andrew s . ▁ ▁Sk or ups ki ▁was ▁President ▁of ▁the ▁Arist ot elian ▁Society ▁in ▁ 1 9 9 0 – 9 1 . ▁He ▁was ▁made