I don't think that Simple Living means/is defined exactly like Minimalism, but I do see that the two are related and even intertwined. The more minimalist I do in various areas of my life, the simpler my living becomes; and the simpler I make my life, it seems the less I have and/or do which - to me - is a form of minimalism.
Edited to add: I believe one's perspective definitely plays a part in one's definition of each.