First published in 2002. This is Volume XV of seventeen in the Library of Philosophy series on Metaphysics. Written in 1939, this book looks at Language and Reality and the Philosophy of Language and the Principles of Symbolism and is related to the movement of Logical Positivism, initiated by Wittgenstein's Tractatus Logico-Philosophicus.

Part I The Philosophy of Language; Chapter I Language and Reality: The Theme of a Philosophy of Language; Chapter II What is Language? Origin and Development the Science of Language; Chapter III Language as the Bearer of Meaning: What it is to Understand; Chapter IV The Phenomenology of Linguistic Meaning: The Primary Functions of Language; Chapter V The Normative Problem of Language: Linguistic Validity; Chapter VI Intelligible Communication: Its Nature and Conditions; Chapter VII Language and Logic: the "Logical Analysis" of Language; Chapter VIII Language and Cognition: The Metalogical Problems of Language; Part II The Principles of Symbolism; Chapter IX The Principles of Symbolism: The General Theory of Symbolism; Chapter X The Language of Poetry and its Symbolic Form; Chapter XI Science and Symbolism: Symbolism as a Scientific Principle; Chapter XII Religious Symbols and the Problem of Religious Knowledge; Chapter XIII The Language of Metaphysics: Symbolism as a Metaphysical Principle; Chapter XIV Philosophia Perennis: The "Natural Metaphysic of the Human Mind";