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Summary: A seminal book of a seminal thinker.
Review: If you are tired of reading summaries and general introductions to philosophy and would like to start reading original works, "Language, Truth and Logic" is a great place to start. The book is clear and concise, and is the classic presentation of logical positivism in English. The concept underlying Ayer's discussion is the "principle of verifiability," which defines a statement as being "literally meaningful" only if it either is logically necessary ("analytical") or can be empirically verified as being either true or false. Under this definition, metaphysical statements are not literally meaningful, and so are properly part of theology rather than philosophy. Ayer believes that many philosophical debates (such as those about ethics or about the nature of the soul) stem from arguing about metaphysical statements as if they were literally meaningful. He believes that once metaphysics has been eliminated from philosophy, these debates will seem silly and the questions that underlie them will be recognized as theological rather than philosophical. So once he has established the principle of verifiability and explained how he identifies statements as either verifiable or analytical, Ayer spends the rest of the book applying this principle to various "philosophical" questions. Of course, the place of metaphysics in philosophy is itself debatable. Ayer's conception of philosophy is relatively narrow, and many readers will prefer a wider definition of philosophy that includes some (or all) of the metaphysical statements that he banishes. Others will be thrilled to finally read a philosophical work that cuts through the mystical goo spread so liberally and destructively by other thinkers. Whether or not one agrees with Ayer's approach and conclusions, one has to appreciate his clear presentation of an important philosophical viewpoint.
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Summary: Logic Positivism -- Period!
Review: There is no better single source of doing philosophy via the logical positivism method than by reading this book. It's really two books in one. The Introduction is a rather thorough reply to his critics of the book's original lengthier substance, and if nothing else is read, the Introduction provides an excellent example of what logical positivism is, why it is regarded highly or poorly depending on the reader, and why some people think this kind of analysis defeats the whole purpose of philosophy. The book does try to end metaphysics as we know it, but in the course of establishing new principles (i.e., verifiability), it itself becomes indefensible against the accusation of itself relying on its own premises to prove its own conclusions (a charge Ayer coyly ignores), otherwise known as circularity. The fact that many Anglo-American philosophers still do philosophy in this manner -- after Ayer's style -- is reason alone to study this book thoroughly. It is concisely written, clear and unambiguious (if not a tad bit too analytical), and exemplary of Anglo-American style of doing philosophy. I don't think too many philosophers subscribe to its own circular metaphysics, but many, if not most, current philosophers adopt its principles as a "method" -- something which Ayer later (in "The Meaning of Life") claims was his aim all along. What is disappointing to me, at least in the body of Ayer's works read thus far, is his failure to address "verifiability" in light of Popper's "falsification" doctrine. What exactly constitutes "verifiability" or empirical truth? And, how does the verification of empirical truth differ from the "empirical falsification" of Popper? Perhaps Ayer addresses this problem somewhere, but I've not found it. It would be an interesting problem to see solved.
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Summary: Philosophy for atheists
Review: This book is an easy to read explanation of the nature of truth. Basically, it outlines two basic types of truth: tautologies (such as those found in mathematics) and empirical facts. All other "facts," such as metaphysical speculations, are considered to be nothing more than nonsensical delusions. This book is to be especially recommended to high school students as a primer for university level studies in philosophy.
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Summary: A. J. Ayer's criterion vs. Karl Popper's criterion
Review: To the previous reviewer: "Nor can we accept the suggestion that a sentence should be something which is definitely confutable by experience . . . This has been proposed by Karl Popper in his Logik der Forschung." ("Language, Truth and Logic", p. 38) A. J. Ayer criterion is based upon the assumption that no scientific theory is either confirmed or refuted "for eternity". In fact, it is both a verifiability/falsifiability criterion since by verifying a sentence one is falsifying its converse. Karl Popper's falsifiability criterion is based upon the assumption that certain scientific theories can be refuted "for eternity" (absolutely) albeit no theory can be confirmed "for eternity".
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