"A delightful book … I should like to have written it myself." — Bertrand Russell
First published in 1936, this first full-length presentation in English of the Logical Positivism of Carnap, Neurath, and others has gone through many printings to become a classic of thought and communication. It not only surveys one of the most important areas of modern thought; it also shows the confusion that arises from imperfect understanding of the uses of language. A first-rate antidote for fuzzy thought and muddled writing, this remarkable book has helped philosophers, writers, speakers, teachers, students, and general readers alike.
Mr. Ayers sets up specific tests by which you can easily evaluate statements of ideas. You will also learn how to distinguish ideas that cannot be verified by experience — those expressing religious, moral, or aesthetic experience, those expounding theological or metaphysical doctrine, and those dealing with a priori truth. The basic thesis of this work is that philosophy should not squander its energies upon the unknowable, but should perform its proper function in criticism and analysis.
Table of ContentsIntroduction
Ch. I. The Elimination of Metaphysics
What is the purpose and method of philosphy?
"Rejection of the metaphysical thesis that philosophy affords us knowledge of a transcendent reality,"
"Kant also rejected metaphysics in this sense, but whereas he accused metaphysicians of ignoring the limits of the human understanding we accuse them of disobeying the rules which govern the significant use of language."
Adoption of verifiability as a a criterion for testing the significance of putative statements of fact.
Distinction between conclusive and partial verification.
No propositions can be conclusively verified.
Or conclusively confuted
For a statement of fact to be genuine some possible observations must be relevant to the deterination of its truth or falsehood.
"Examples of the kinds of assertions, familiar to philosphers, which are ruled out by our criterion."
Metaphysical sentences defined as sentences which express neither tautologies nor empirical hypotheses.
Linguistic confusions the prime source of metaphysics.
Metaphysics and Poetry.
Ch. II. The Function of Philosophy
Philosophy is not a search for first principles.
Barrenness of Descartes' procedure.
The function of philosophy is wholly critical.
But this does not mean that it can give an a priori justification of our scientific or common-sense assumptions.
"There is no genuine problem of induction, as ordinarily conceived."
Philosophising is an activity of analysis.
"Most philosophers in our sense, rather than metaphysicuabs,"
"Locke, Berkeley, Hume as analysts."
We adopt Berkeley's phenomenalism without his theism.
And take a Humean view of causation.
Philosophy in our doctrine of atomism.
"The philosopher as an analyst is not concerned with the physical properties of things, but only with the way in which we speak about them."
Linguistic propositions disguised in factual terminology.
Philosophy issues in definitions.
Ch. III. The Nature of Philosophical Analysis
"Philosophy provides not explicit definitions, such as are given in dictionaries, but definitions in use."
Explanation of this distinction.
"Russell's "theory of descriptions" as an example of philosophical analysis."
Definition of an ambiguous symbol.
Definition of a logical construction.
Material things are logical constructions out of sense-contents.
By defining the notion of a material thing in terms of sense-contents we solve the so called problem of perception.
A solution of this problem outlined as a further example of philosophical analysis.
Utility of such analyses.
Danger of saying that philosphy is concerned with meaning.
The propositions of philosophy are not empirical propositions concerning the way in which people actually use words.
They are concerned with the logical consequences of linguistic conventions.
"Rejection of the view that "every language has a structure concerning which in the language nothing can be said."
Ch. IV. The A Priori
"As empiricists, we must deny that any general proposition concerning a matter of fact can be known certainly to be valid."
How then are we to deal with the propositions of formal logic and mathematics?
Rejection of Mill's view that these propositions are inductive generalisations.
They are necessarily true because they are analytic.
Kan'ts definitions of analytic and synthetic judgments.
Emendation of Kant's definitions.
Analytic propositions are tautological; they say nothing concerning any matter of fact.
"But they give us new knowledge, inasmuch as they bring to light the implications of our linguistic usages."
"Logic does not describe "the laws of thought."
Nor geometry the properties of physical space.
Our account of a priori truths undermines Kant's transcendental system.
"How, if they are tautological, can there be in mathematics and logic the possibility of invention and discovery?"
Ch. V. Truth and Probability
What is truth?
Definition of a proposition.
"The words "true" and "false" function in the sentence simply as assertion and negation signs."
"The "problem of truth" reduced to the question."
How are propositions validated?
The criterion of the validity of empirical propositions is not purely formal.
"No empirical propositions are certain, not even those which refer to immediate experience."
Observation confirms or discredits not just a single hypothesis but a system of hypotheses.
"The "facts of experience" can never compel us to abandon a hypothesis."
Danger of mistaking synthetic for analytic propositions.
Hypotheses as rules which govern our expectation of future experience.
Definition of rationality.
Definition of probability in terms of rationality.
Propositions referring to the past.
Ch. VI. Critique of Ethics and Theology
How does an empiricist deal with assertions of value?
Distinction between verious types of ethical enquiry
Utilitarian and subjectivist theories of ethics consistent with empiricism.
But unacceptable on other grounds.
Distinction between normative an descriptive ethical symbols.
Rejection of intuitionism.
"Assertions of value are not scientific but "emotive."
They are therefore neither true nor false.
"They are partly expressions of feeling, partly commands."
Distinction between expressions and assertions of feeling.
Objection that this view makes it impossible to dispute about questions of value.
"Actually, we never do dispute about questions of value, but always about questions of fact."
Ethics as a branch of knowledge comprehended in the social sciences.
The same applies to æsthetics.
Impossibility of demonstrating the existence of a transcedent god.
Or even of proving it probable.
"That a transcedent god exists is a metaphysical assertion, and therefore not literally significant."
Saying this does not make us atheists or agnostics in the ordinary sense.
The belief that men have immortal souls is also metaphysical.
There is no logical ground for conflict between religion and science.
Our views supported by the statements of theists themselves.
Refutation of the argument from religious experience.
Ch. VII. The Self and the Common World
The basis of knowledge.
"Sense-contents as parts, rather than objects, of sense-experiences."
Sense-contents netiher mental nor physical.
Distinction between the mental and the physical applies only to logical constructions.
The existence of epistemological and causal connections between minds and material things open to no a priori objections.
Analysis of the self in terms of sense-experiences.
A sense-experience cannot belong to the sense-history of more than one self.
The substantive ego a fictitious metaphysical entity.
Hume's definition of the self.
That the empirical self survives the dissolution of the body is a self-contradictory proposition.
Does our phenomenalism involve solipsism?
Our knowledge of other people.
How is mutual understanding possible?
Ch. VIII. Solutions of Outstanding Philosophical Disputes
"The nature of philosophy does not warrant the existence of conflicting philosophical "parties."
The conflict between rationalists and empiricists.
Our own logical empiricism to be distinguished from positivism.
"We reject Hume's psychological, as opposed to his logical, doctrines."
Realism and Idealism.
To say that a thing exists is not to say that is is actually being perceived.
Things as permanent possibilities of sensation.
What is perceived is not necessarily mental.
What exists need not necessarily be thought of.
Nor what is thought of exist.
Empirical grounds for supposing that things may exist unperceived.
Monism and Pluralism.
Monistic fallacy that all a thing's properties are constitutive of its nature.
Illustrates the danger of expressing linguistic propositions in factual terminology.
Causality not a logical relation.
Empirical evidence against the monist's view that every event is causally connected with every other.
The unity of science.
Philosophy as the logic of science.