The philosophical approach of this volume is mainly structuralist, using logical tools to investigate the formal structure of various kinds of objects in our world, as characterised by language and as systematised by philosophy. This volume mainly analyses the structural properties of collections or pluralities (with applications to the philosophy of set theory), homogeneous objects like water, and the semantics and philosophy of events. This book thereby complements algebraic work that has been done on other philosophical entities, i.e. propositions, properties, relations, or situations. Located in the triangle of language, logic and philosophy, this volume is unique in combining the resources of different ?elds in an interdisciplinary enterprise. Half of the fourteen chapters of this volume are original papers, complementing the collection of the author's previously published essays on the subject.