PHIL 4150: Analytic Philosophy
Dr. Robert Lane
Lecture Notes: Thursday October 18, 2012


[] In-Principle vs. In-Practice Verifiability.


in-principle verifiability (df.): “p” can be verified in principle if and only if we can describe sensory observations that would show “p”  to be true or that would show “p”  to be false, even if we cannot in fact make those observations.


in-practice verifiability (df.): “p”  can be verified in practice if and only if we can actually make observations that would show “p”  to be true or that would show “p”  to be false.


The verification required by Ayer’s version of the VP is in-principle verifiability, not in-practice verifiability, i.e., if a statement cannot in practice be shown to be true or false by our experiences, that does not render it meaningless. What’s required for a sentence to be empirically meaningful is only that we be able to describe observations that would go to show that it is true or false, even if we cannot in fact make those observations.


Ayer gives the example of the claim that there are mountains on the dark side of the moon… when he wrote LTL, it was not practically possible to travel to the moon and make such observations. (501) But even at that time such observations were possible in principle—you could describe the kinds of observation that you have to make in order to verify the claim (namely, going to the dark side of the moon and looking).


As an example of a metaphysical sentence that is not verifiable, even in principle, Ayer cites the following:


“the Absolute enters into, but is itself incapable of, evolution and progress.” F.H. Bradley, Appearance and Reality (1893; 2nd ed. published in 1897; quoted by Ayer at 501)


F. H. Bradley (1846-1924) was one of the so-called British Idealists against whom Russell and Moore rebelled.[1] He defended a form of


absolute idealism (df.): belief in a God—“Absolute Mind”—that is present everywhere and in all things. This is a sort of secular, philosophical concept of God that played a role in the philosophical systems of many philosophers during the 19th and early 20th centuries.[2]


According to Ayer, the sentence he quoted from Bradley “is not even in principle verifiable. For one cannot conceive of an observation which would enable one to determine whether the Absolute did, or did not, enter into evolution and progress.” (501)



[] Strong vs. Weak Verifiability.


strong verifiability (df.):p”  is strongly verifiable if and only if there are observations that would show “p” to be true or false conclusively, with certainty.


weak verifiability (df.): “p”  is weakly verifiable if and only if there are observations that are relevant to the determination of “p”  being either true or false.


Ayer said that the VP should not be understood as requiring strong verification, because in that case the following kinds of meaningful propositions will turn out to be meaningless:


So he urged that the VP be understood as requiring only weak verifiability.



[5.3.2.] Against “Transcendent Metaphysics.”


Ayer criticized what he calls “transcendent metaphysics,” i.e., metaphysics that makes claims that go beyond (transcend) possible human experience. Such claims will be a priori, since they are not a posteriori, but they would not be analytic (mere definitions or logical truths), and so they would have to be synthetic.


So Ayer, like the members of the Vienna Circle, was targeting the synthetic a priori.


… one cannot overthrow a system of transcendent metaphysics merely by criticizing the way in which it comes into being. What is required is rather a criticism of the nature of the actual statements which comprise it. And this is the line of argument which we shall, in fact, pursue. For we shall maintain that no statement which refers to a “reality” transcending the limits of all possible sense-experience can possibly have any literal significance; from which it must follow that the labours of those who have striven to describe such a reality have all been devoted to the production of nonsense. (499-500)


Some examples of “transcendent metaphysics”—metaphysical statements and debates that get ruled out as meaningless by the VP--are as follows:


“The world of sense experience [is] altogether unreal.” (502) In other words: the world that we experience through our senses is not real—it is “mere appearance,” not reality. (Although Ayer does not mention Plato here, this claim is suggestive of Plato’s metaphysics, according to which the world we experience through the senses is less real than the Forms that we come to know through thinking. On one interpretation, Kant held something like the view that Ayer criticizes here.) Says Ayer:


[I]t is plain that no conceivable observation, or series of observations, could have any tendency to show that the world revealed to us by sense-experience was unreal. Consequently, anyone who condemns the sensible world as a world of mere appearance, as opposed to reality, is saying something which, according to our criterion of significance, is literally nonsensical. (502)


The debate between monism (reality is a single “substance”—thing or object) and pluralism (reality is many different “substances”—things or objects).

·         The question posed here can be restated as follows: is the universe a single thing, or is it made up of many different things?

·         An example of philosophers who argued about this: Spinoza (1632-1677), who maintained that the universe is a single substance (namely, God) and that everything in it is simply a mode or aspect of that one substance, and Leibniz (1646-1716), who held that the universe consists of infinitely many substances (which he called monads).


[I]f we are told that no possible observation could give any probability either to the assertion that reality was one substance or to the assertion that it was many, then we must conclude that neither assertion is significant. … [T]he metaphysical question concerning ‘substance’ is ruled out by our criterion as spurious i.e., as false or fake]. (502)


The debate between realism (ordinary objects—books, tables, trees, the sun, etc.—are objectively real) and idealism (ordinary objects are not objectively real but are instead ideas in the mind of the perceiver, or in the mind of God).

·         An example of philosophers who disagreed about this: René Descartes (1594-1650) maintained that ordinary objects are objectively real, while Bishop George Berkeley (1685-1753) maintained that ordinary objects are ideas in the mind of human perceivers (and, in the case of things not perceived by any human, ideas in the mind of God).

·         Ayer illustrates this debate by first asking us to consider a disagreement about whether a specific work of art was painted by a specific painter (the Spanish artist Francisco Goya, 1746-1828). We know what sorts of empirical observation we can make to help settle this question: experts can examine the work to see whether it is very similar to other works which they know to have been created by Goya and whether it properties that other known forgeries have had, and they can conduct research into the historical records to see whether there is independent evidence of such a work having been created by Goya.

·         But what sorts of empirical evidence are relevant to the question whether the painting is objectively real or whether it is an idea in a perceiver’s mind, or in God’s mind? According to Ayer: none whatsoever. So “the problem is fictitious.” (503)



Thus, Ayer concludes that all transcendent metaphysical claims fail to live up to the Verification Principle and are thus literally meaningless. He views the claims of ethics and of religion in the same way. About religion, he says, for example, the following:


It is common to find belief in a transcendent god conjoined with belief in an after-life. But, in the form which it usually takes, the content of this belief is not a genuine hypothesis. To say that men do not ever die, or that the state of death is merely a state of prolonged insensibility, is indeed to express a significant proposition, though all the available evidence goes to show that it is false. But to say that there is something imperceptible inside a man, which is his soul or his real self, and that it goes on living after he is dead, is to make a metaphysical assertion which has no more factual content than the assertion that there is a transcendent god. (LTL 117; not in your textbook)



The next philosopher we will study, C. L. Stevenson, applies the approach of the logical positivists to ethical discourse.



Stopping point for Thursday October 18. For next time, begin reading C. L. Stevenson, “The Emotive Meaning of Ethical Terms,” sections I through III (pp.450-455).



[1] For more on Bradley, see Stewart Candlish and Pierfrancesco Basile, “Francis Herbert Bradley,”, The Stanford Encyclopedia of Philosophy (Spring 2009 Edition), Edward N. Zalta (ed.), URL =, accessed October 8, 2012.


[2] Contemporary philosopher Timothy Sprigge (1932-2007) states the central thesis of absolute idealism this way: “there is one unitary world consciousness or experience which includes everything else which exists.” (“James, Empiricism, and Absolute Idealism,” in Shook and Margolis, eds., A Companion to Pragmatism, Blackwell, Malden, MA, 2006, p.166; Ingram Library owns a copy of this reference book, and you can also access an electronic copy through GALILEO, but only if you are on campus). Sprigge reports that “absolute idealism was the dominant philosophy in the English-speaking world throughout the period in which James worked out his ideas.” (op. cit.) Among the philosophers who defended various forms of absolute idealism were Friedrich Schelling (1775–1854), Georg Hegel (1770–1831), and, in James’s lifetime, Josiah Royce (1855-1916), T. H. Green (1836-1882), F. H. Bradley (1846-1924), and Bernard Bosanquet (1848-1923). Sprigge himself defended a version of absolute idealism in his books The Vindication of Absolute Idealism (1984) and The God of Metaphysics (2006).