Samuel C. Rickless presents a novel interpretation of the thought of George Berkeley. In 'A Treatise Concerning the Principles of Human Knowledge' (1710) and 'Three Dialogues Between Hylas and Philonous' (1713), Berkeley argues for the astonishing view that physical objects (such as tables and chairs) are nothing but collections of ideas (idealism); that there is no such thing as material substance (immaterialism); that abstract ideas are impossible (anti-abstractionism); and that an idea can be like nothing but an idea (the likeness principle). It is a matter of great controversy what Berkeley's argument for idealism is and whether it succeeds. Most scholars believe that the argument is based on immaterialism, anti-abstractionism, or the likeness principle.