This volume consists of Yasuhiko Tomida's notable essays on Locke, Berkeley, and Kant, as well as a thought-provoking article written in collaboration with an experimental physicist. Tomida asserts that the logical space of the theory of ideas is originally "naturalistic" in Quine's sense of the term and that Berkeley and Kant 'distort' it in their respective ways, thus offering a wholly new viewpoint concerning the historiography of the theory of ideas. The revised and enlarged second edition carries one more article on Locke's holistic logic.