This thesis argues that the aesthetic character of some conceptual works of art can be determined by the possession of essential aesthetic properties. By discussing Peter Lamarque’s account of individual aesthetic essentialism one can suggest that conceptual works can be aesthetically investigated. Chapter I introduces the concept of the aesthetic and discusses Frank Sibley’s account of aesthetic concepts. Chapter II analyses in detail Sibley’s two fold relational character of aesthetic properties. Chapter III introduces Lamarque’s concept of aesthetic properties and it (...) also insists on a distinction between artistic and aesthetic properties. Chapter IV introduces a general account of essentialism and then discusses Lamarque’s new object theory. Chapter V investigates Lamarque’s weaker version of individual aesthetic essentialism and analyses the distinction between essential and inessential aesthetic properties. Finally, Chapter VI considers the aesthetics of conceptual art and argues that some conceptual pieces have essential aesthetic properties. The philosophical discussions are supported by appeal to many different works of art, from traditional works to contemporary works. I conclude that all conceptual works have aesthetic properties but mostly there are inessential properties. My suggestion at the end of this thesis is more radical. A close analysis identified essential aesthetic properties in some conceptual works of art and this contribute to the aesthetic character and value of these works. (shrink)