In this book, the author of "Language, Truth and Logic" tackles one of the central issues of philosophy - how we can know anything - by setting out all the sceptic's arguments and trying to counter them one by one.
A. J. Ayer was one of the foremost analytical philosophers of the twentieth century, and was known as a brilliant and engaging speaker. In essays based on his influential Dewey Lectures, Ayer addresses some of the most critical and controversial questions in epistemology and the philosophy of science, examining the nature of inductive reasoning and grappling with the issues that most concerned him as a philosopher. This edition contains revised and expanded versions of the lectures and two additional essays. Ayer (...) begins by considering Hume's formulation of the problem of induction and then explores the inferences on which we base our beliefs in factual matters. In other essays, he defines the three kinds of probability that inform inductive reasoning and examines the various criteria for verifiability and falsifiability. In his extensive introduction, Graham Macdonald discusses the arguments in _Probability and Evidence_, how they relate to Ayer's other works, and their influence in contemporary philosophy. He also provides a brief biographical sketch of Ayer, and includes a bibliography of works about and in response to _Probability and Evidence_. (shrink)
The criterion of truth is the measure of the truthfulness and reliability of our knowledge. It is also the basis for determining the correctness of our concepts and how much our perceptions, ideas, and concepts accord with objective reality. Idealism holds to the idea that the criterion of truth does not involve the integration between theory as created by human intelligence and objective reality, but rather that the criterion of truth involves the "clarity and correctness" of perception, viewpoints, and concepts (...) by the subject. For instance, the Machists 1 think that the criterion of truth is experience, however, they neither interpret experience from a materialistic viewpoint, nor view experience as the result of humans interacting with nature as they reform it. The Machists view experience as a summary of perceptions and as the subjective experience of humans. In this sense, perception must be tested by perception itself. In attempting to escape the trap of solipsism , they proposed "collective experience" as the criterion of truth. According to such a view, anything that involves "common significance," that is, anything acknowledged by everyone, is the truth. Lenin exposed the absurdity of idealist theory by pointing out that by following the view of "socially formed experience" it is very easy to consider as normal the most absurd and farcical notions, such as ghosts, for such beliefs are also a form of human "experience." Religion also possesses a "common significance," for innumerable people believe in ghosts and miracles, etc. Nevertheless, religion does not become the truth because of this. The concept of the "criterion of truth" held by the Machists played a dominant role in modern bourgeois philosophy. Jean Jacques Rousseau and John Dewey, along with other reactionaries in philosophy all denied scientific criteria. They would rather that the masses remain ignorant of how to understand and determine the truth. (shrink)