This project is about the representation of particular objects in language and thought, a topic which has been at the forefront of philosophical attention for more than a century. About fifty years ago, ‘descriptivism’ was demoted from its dominant position in philosophy in favour of the theory of ‘direct reference’. A similar shift away from descriptivism has been a noticeable feature of work on the representation of objects in cognitive science, where the notion of an ‘object file’ has made it possible to unify research on perception and on infant cognition. The object file construct is in many respects similar to the philosophical idea of direct (non-descriptive) grounding for thoughts about particulars, and this has given rise to a new research program: the generalization of the file idea from perception to thought. Thus the last decade has seen the development of the mental file framework, according to which nondescriptive thoughts about particulars (so-called ‘singular thoughts’), whether or not they are based on perception, involve mental files whose 'reference' does not depend on category information to be found in the file but on certain relations to the object the obtaining of which triggers the opening of the file. The mental file framework has attracted considerable attention not only in philosophy, but also in psychology (Perner) and linguistics (Kamp). It has also inspired work in aesthetics and the philosophy of fiction. Successful though it is, the mental file framework currently faces what may be described as a foundational crisis. According to a recurrent piece of criticism, it fails to provide appropriate identity and persistence conditions for mental files. This threatens the credibility of the framework, reduced to a convenient metaphor, and puts it at risk despite its high promises and considerable appeal. The aim of this philosophical project is to end the crisis by entirely rethinking the foundations of the framework.