As the title indicates, this thesis is a critical exposition of Armstrong's theory of universals. But at a deeper level it is also an argument against one of the main tenets of traditional realism since Plato: the claim that the nature of physical properties, and objects in general, are ontologically independent of any mind or belief system. Armstrong's attempt to argue for a non-relational immanent realism epitomizes this claim. Armstrong's main argument for his position is an indirect one. He argues for the untenability of all theories opposing his and then attempts to show how his theory does not suffer from the same problems. Against theories opposing his (all forms of nominalism and transcendent Platonic realism) he puts forth four arg...