Metaphysical orthodoxy holds that a privileged minority of properties carve reality at its joints. These are the so-called fundamental properties. This thesis concerns the contemporary philosophical debate about the nature of fundamental properties. In particular, it aims to answer two questions: What is the most adequate conception of fundamental properties? What is the “big picture” world-view that emerges by adopting such a conception? I argue that a satisfactory answer to both questions requires us to embrace a novel conception of powerful (...) qualities, according to which properties are at once dispositional and qualitative. By adopting the proposed conception of powerful qualities, an original theory of fundamental properties comes to light. I call it Dual-Aspect Account. In this thesis, I defend the Dual-Aspect Account and its superiority with respect to rival views of fundamental properties. I illustrate this claim by examining Dispositionalism, the view defended among others by Alexander Bird and Stephen Mumford, Categoricalism, which has been advocated notably by David Lewis and David Armstrong, and the Identity Theory of powerful qualities, primarily championed by C. B. Martin and John Heil. The latter is the standard conception of powerful qualities. However, in the literature, the Identity Theory faces the charge of contradiction. A preliminary task is therefore to show that a conception of powerful qualities is coherent. To accomplish this aim, I introduce the notion of an aspect of a property. On this interpretation, powerful qualities can be thought of as having dispositional and qualitative aspects. I show that such a conception allows us to disambiguate the claim that a property’s dispositionality is identical with its qualitativity, and evade the charge of contradiction. Aspects bring us other theoretical benefits. I illustrate this claim by showing how the Dual-Aspect Account offers us a promising theory of resemblance. I then compare its merits with David Armstrong’s theory of partial identity. The conclusion of this thesis is that the Dual-Aspect Account is better suited to capturing the world as we find it in everyday life and scientific investigation as compared to the theoretical positions examined. (shrink)