PHIL 4150: Analytic Philosophy
Dr. Robert Lane
Lecture Notes: Tuesday October 16, 2012


[5.2] Logical Positivism.



[5.2.1.] The Vienna Circle


In the 1920s in Vienna, Austria, a group of philosophers known as the Vienna Circle developed a view of meaning that had serious consequences for metaphysics and other areas of philosophy.


Members of the Vienna Circle included:

·         Moritz Schlick (1882-1936)

·         Friedrich Waismann (1896-1959)

·         Otto Neurath (1882-1945)

·         Rudolf Carnap (1891-1970)


An important associate of the Vienna Circle was A. J. Ayer (about whom more later).


The Vienna Circle was deeply influenced by Wittgenstein’s Tractatus, although they did not accept all of its claims.


The members of the Vienna Circle, as well as Ayer, embraced the following position:


logical positivism (df): There are only two types of meaningful statement:

(1)   statements that are true or false solely because of the meanings of their words (“All bachelors are unmarried”; “Some squares have three sides”)

(2)   statements that can be shown to be true or false by way of experience (“This thermos contains water”; “The earth is orbited by two moons”).

All other statements are meaningless.

·         This view is also known as logical empiricism.


As we will see, the Vienna Circle and Ayer took logical positivism to have negative implications for metaphysics (as well as for ethics, aesthetics, and religion).



[5.2.2.] Background: Metaphysics.


metaphysics (df.): the area of philosophy concerned with questions about reality and existence; traditionally, metaphysics has been considered to be one of the central areas of philosophy, along with ethics, logic and epistemology.


The most basic metaphysical question is: what is there?


Metaphysics is not concerned to find very specific answers to such questions. For example, it is not looking for answers like: “There are 25 desks in this room; there is water on Mars; there is a recess in the Michael Vick trial.” It is not even concerned with more general, but still specific, answers: “there are desks; there is water; there are trial recesses.”


Rather, it is concerned with the most general sorts of answer: there is matter (i.e., physical objects), there are qualities (properties, traits, characteristics), there are kinds.


Following that most basic metaphysical question (“what is there?”), there is the question: what is the nature of what there is?


Other, slightly more general questions, also belong to metaphysics: what do the words “is” and “are” mean? What is existence? What is being, i.e., what is it to be?


Still other, slightly more specific questions have traditionally been viewed as belonging to metaphysics:

·         what is the difference between the actual and the merely possible?

·         what is the nature of causation?

·         does God (or gods) exist? if so, what is the nature of God? [this is now dealt with within philosophy of religion]

·         are minds non-physical and independent of brains, or physical and identical with brains, or something else? [this is now dealt with within philosophy of mind]

·         what is free will, and do humans have it? [this is now dealt with within philosophy of action]



[] “Metaphysics” and “Ontology.”


The term “metaphysics” was coined when it was given by Andronicus to the body of work directly following the Physics in the edited works of Aristotle. In Greek, the literal meaning of “metaphysics” was “after Physics.” (Aristotle himself called that work “first philosophy.”)


The word “ontology” is used to refer to a list of the things (or types of thing) that have being, i.e., of the things (or types of thing) that there are. For example, one philosopher may have an ontology that includes only physical objects (such a philosopher believes that the only things there are, are physical objects); another may have an ontology consisting of physical objects, non-physical minds, and God (such a philosopher, e.g., Descartes, thus believes the only things there are, are physical objects, non-physical minds, and God).


But sometimes “ontology” is used to refer, not to a list of fundamental types of thing, but to the branch of metaphysics that tries to come up with such a list. In this sense, ontology itself is an area of metaphysics. Some people use the terms “ontology” and “metaphysics” interchangeably.



[] Two Attitudes About Metaphysics in the Analytic Tradition.


Philosophers have been engaged in metaphysics since before Socrates. For example, the so-called pre-Socratics were Greek philosophers who espoused theories about the nature of the physical world (e.g., Thales claimed that everything was made of water; Anaximenes claimed that everything was made of air, etc.)


This continued with Plato and Aristotle, through the medieval period and into the modern period (with Descartes, Spinoza, Leibniz, Locke, Berkeley, Hume and Kant).


The Tradition of Analytic Philosophy is no exception. Many philosophers in this tradition were concerned with metaphysics. We have already seen a bit of metaphysics in the philosophers we’ve studied so far:

·         Frege: the claim that there is a third realm of senses associated with expressions and propositions, and which exists outside the mind, is a metaphysical claim. It illustrates how metaphysics and philosophy of language sometimes overlap.

·         The Early Wittgenstein: the claim that the world consists of (non-atomic) facts, which themselves are composed of atomic facts (which in turn are composed of objects arranged in definite ways), is also a metaphysical claim. But as we have seen, Wittgenstein himself had an odd attitude towards that claim, and towards all of the Tractatus: he held that the entire book was, strictly speaking, meaningless. He thought this because the metaphysical claims in that book do not live up to his own standard of meaning: the sentences of the Tractatus cannot picture the world in the way that a meaningful claim must. As we have seen, the final line in the book is: “Whereof one cannot speak, thereof one must be silent.” So the early Wittgenstein exhibits an odd combination of positive and negative attitudes toward metaphysics.


Other philosophers in the tradition exhibited very different attitudes toward metaphysics:


1.      Positive: metaphysics is a legitimate enterprise to which philosophers should contribute. Many philosophers in the Analytic Tradition put forward their own metaphysical claims and theories.


2.      Negative: metaphysics is not a legitimate enterprise. Others in the Analytic Tradition argued against metaphysics itself, e.g., by arguing that metaphysical claims are meaningless. This group includes the logical positivists.



[] Historical Background: Kant.


To really understand logical positivism (LP), we need to go back in time, to the eighteenth century, to the work of Prussian philosopher Immanuel Kant (1724-1804).[1]


Kant employed a pair of distinctions which have been widely used within philosophy ever since.


One of these we’ve seen before: the distinction between the a priori and the a posteriori.


The other distinction is new for us: the distinction between the analytic and the synthetic.


Kant applied these distinctions to “judgments” (by which he meant a sort of mental operation, something that the mind does).


analytic (df.): an analytic judgment contains nothing in the concept of the predicate not already thought in the concept of the subject (e.g., “Bachelors are unmarried”).


synthetic (df.): a synthetic judgment is one which is not analytic (e.g., “Some philosophers are bachelors”).



This is a distinction between two different types of truth.

a priori (df.): an a priori judgment is one that can be known to be true or false independently of sense experience.



a posteriori (df.): an a posteriori judgment is one that can be known to be true or false only by sense experience.



This is an epistemological distinction between two different types of knowledge.


The combination of these two distinctions yields four possible categories of judgment... This table shows the sorts of judgment that Kant thought belonged to each of the four categories:





 a priori

trivial verbal judgments (“Unmarried males are male”; “Bachelors are unmarried”).

mathematics (e.g., “7 + 5 = 12”) & metaphysics (e.g., “Every event has a cause”).

a posteriori




natural science, history, commonsense empirical knowledge


Synthetic a priori judgments would be (i) non-trivial, interesting judgments about the world which (ii) we can know prior to any particular sense experience.


Kant’s category of synthetic a priori is controversial. Prior philosophers had maintained that such judgments were impossible. Kant himself took it to be an important philosophical task to explain how they are possible. He tried to give such an explanation in his book, Critique of Pure Reason.


[Recall that Frege and Russell had each argued for logicism, according to which mathematical statements are, at bottom, really statements of logic. If they were right about this, then mathematical statements are a priori and analytic, rather than synthetic as Kant had maintained.]



[5.2.3.] Against Metaphysics: the Verification Principle. 


The Logical Positivists had no problem with the analytic a priori or the synthetic a posteriori. But they rejected the synthetic a priori.


They gave the following classification of statements (notice that they are focusing on language rather than on mental judgments as Kant had done):


cognitively meaningful statements

cognitively meaningless statements

logical meaning:



(i.e., the analytic a priori)

empirical* meaning:


historical statements

common-sense empirical


(i.e., the synthetic a posteriori)


*empirical (df.): having to do with sensory experience or observation

religious discourse






The positivists thought that metaphysics, religion, etc. are meaningless because they accepted the following standard of empirical meaning:


The Verification Principle (df.): A sentence S is empirically meaningful if and only if S is verifiable by experience, i.e., S can shown to be true or false by means of the senses.


Another name for the positivists’ position regarding empirical meaning is “the testability theory of meaning”; in order for a statement to have empirical meaning, it must be possible to test it by way of sensory experience in order to determine whether it is true or false.


Different positivists developed the Verification Principle in different ways. Below we will consider the way in which Ayer developed it…



[5.3.] Alfred Jules (A. J.) Ayer.


·         1910-1989

·         Born in London

·         Beginning in 1929, he attended college at Oxford, where he was the student of philosopher Gilbert Ryle. Ryle suggested that he read Wittgenstein’s Tractatus, by which Ayer was very impressed, and that he travel to Vienna to study with Moritz Schlick of the Vienna Circle.

·         Back from Vienna, he returned to Oxford and, while only 24 years old, wrote Language, Truth and Logic (1936). This was a widely read explanation and defense of logical positivism. With its publication, Ayer became an emissary for logical positivism from continental Europe to the rest of the world. Your reading, “The Elimination of Metaphysics,” is the first chapter of that book.

·         In the following years he continued to refine his version of logical positivism, and this resulted in a second book, Foundations of Empirical Knowledge. He taught at various prestigious schools both in England and elsewhere and continued writing and publishing philosophy until late in his life.

·         He had many famous friends, including Bertrand Russell, George Orwell, ee cummings, Iris Murdoch, and Christopher Hitchens.[2]


Ayer defended a version of the redundancy theory of truth: “in all sentences of the form ‘p is true’, the phrase ‘is true’ is logically superfluous. When, for example, one says that the proposition ‘Queen Anne is dead’ is true, all that one is saying is that Queen Anne is dead.” (LTL p.88; not in your textbook).



[5.3.1.] Ayer’s Verification Principle.


Ayer stated the Verification Principle as follows:


[A] sentence is factually significant to any given person, if, and only if, he knows how to verify the proposition which it purports to express—that is, if he knows what observations would lead him, under certain conditions, to accept the proposition as being true, or reject it as being false. If, on the other hand, the putative proposition is of such a character that the assumption of its truth, or falsehood, is consistent with any assumption whatsoever concerning the nature of his future experience, then, as far as he is concerned, it is, if not a tautology, a mere pseudo-proposition. (500)


But this statement does not provide every important detail about Ayer’s version of the Principle. To really understand how he interpreted the principle, we need to attend to two important distinctions:

·         in-principle verifiability vs. in-practice verifiability

·         strong verification vs. weak verification


As we will see, Ayer understood the Verification Principle to involve weak, in-principle verification…




Stopping point for Tuesday October 16. For next time, no new reading (I thought it would take only one day to work through Ayer, but it will take us two days—so we are one day behind schedule). I will update the online course schedule to take account of this. The next reading [C. L. Stevenson, “The Emotive Meaning of Ethical Terms,” sections I through III (pp.450-455)] will now be due on Tuesday October 23.


Your mandatory term paper draft is due on Thursday November 1.




[1] For more on Kant, see this article in the Routledge Encyclopedia of Philosophy: .


[2] These biographical details are taken from Graham Macdonald, “Alfred Jules Ayer,” The Stanford Encyclopedia of Philosophy (Winter 2010 Edition), Edward N. Zalta (ed.), URL =, retrieved October 8, 2012.

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