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Logical Positivism: Is Metaphysics Meaningless?

Does metaphysics lack meaning? This question might come as a shock to many philosophers, particularly theologians, but others will give an emphatic “yes” in response. Most notably the logical positivists, and among them the most vocal being Moritz Schlick (1882-1936) and Rudolf Carnap (1891-1970). According to them, if a thing is not empirically verifiable, it simply has no meaning.

Schlick says, “metaphysics collapses not because the solving of its tasks is an enterprise to which the human reason is unequal… but because there is no such task.” [Ayer: 57] Carnap says, “Whether or not these questions can be answered, it is at any rate unnecessary to worry about them.” [Ayer: 60] Essentially, all questions that cannot be answered scientifically are a waste of time, no more important than trying to determine how many angels can dance on a pin head or wondering why unicorns are hollow. In this essay, I wish to present their view on metaphysics as expressed in the collection titled Logical Positivism, edited by A. J. Ayer.

What is Metaphysics?

In order to know what claims are being made, we must first identify what it is we mean by the term “metaphysics”. A formal definition may be: “The study of the fundamental nature of being and reality; supposedly distinct from physics, as it attempts to consider issues concerning the existence and nature of non-physical entities, or the nature of being and reality as such (in itself).” Carnap defines “metaphysics” as “the field of alleged knowledge of the essence of things which transcends the realm of empirically founded, inductive science.” [Ayer: 80] In simpler terms, metaphysics discusses things in the world which cannot be analyzed through our senses or with the scientific method.

Metaphysics may include discussion of universals as actual entities, the Platonic Ideas, Kant’s “thing in itself” or any other suggested theory that is mere speculation and can never be independently verified.

Metaphysics would not include such things as the speculation about quantum particles or undiscovered celestial objects. While these things may not have been directly observed (yet), their existence is hypothesized on the basis of current scientific knowledge and not from any source outside of the realm of math or logic. It remains likely that, should such things exist, they will one day be discovered through scientific means.

Using Physics to Explain Metaphysics

Carnap talks about “the impossibility of any metaphysics which tries to draw inferences from experience to something transcendent which lies beyond experience and is not itself experienceable” [Ayer: 145] He uses the Kantian “thing in itself” as an example. Quite simply, experience can only explain experience. Anything beyond that can not be “inferred” or “deduced”, at least not with any degree of reliability.

Schlick again says it has been said “that metaphysics is the theory of ‘true being’… (and this) implies a (contradictory) spurious, lesser, apparent being… (which) amounts to identifying the ‘given’ of the positivist with the ‘appearances’ of metaphysics”. [Ayer: 83] He believes the opposite: “the world of the non-metaphysician is the same world as that of all other men; it lacks nothing which is needed to bestow meaning on all the propositions of science and the whole conduct of life. He merely avoids adding meaningless statements to his description of the world.” [Ayer: 105]

In essence, Schlick is arguing for common sense. Why should we say the world we experience is “false” and the true world is unknowable? This adds another facet to the universe that need not be there: perhaps what we see is really what exists. Is there a good reason to believe otherwise? Philosophers, as brilliant as they may be, have a tendency to make life more complicated than the lay person. But here, if the lay person says they see a brown table, they probably do see a brown table and not some “apparent” thing with the reality unknown to man.

The Distinction Between ‘False’ and ‘Meaningless’

Schlick explains that metaphysics cannot be affirmed or denied, only ignored: “The denial of the existence of of a transcendent external world would be just as much a metaphysical statement as its affirmation. Hence the consistent empiricist does not deny the transcendent world, but shows that both its denial and affirmation are meaningless.” [Ayer: 107] Continuing on, he says, “This last distinction is of the greatest importance. I am convinced that the chief opposition to our view derives from the fact that the distinction between the falsity and the meaninglessness of a proposition is not observed. The proposition ‘Discourse concerning a metaphysical external world is meaningless’ does not say: ‘There is no external world,’ but something altogether different. The empiricist does not say to the metaphysician ‘what you say is false,’ but, ‘what you say asserts nothing at all!’ He does not contradict him, but says ‘I don’t understand you.'” [Ayer: 107]

This is probably the most easily misunderstood part of the logical positivist view of metaphysics. Metaphysical things like angels, gods, demons, universals, Ideas and more are not declared false or wrong. Could these things exist? Very possibly. However, as they cannot be affirmed empirically, any discussion of them lacks meaning. They are meaningless in any real sense. Not false, just unprovable. We could debate the properties of archangels, but as we can never verify our claims (at least not in this life), why bother? Our intellectual pursuits are best followed in other categories.

Carnap says, “The physical language is universal and inter-subjective. This is the thesis of physicalism. If the physical language, on the grounds of its universality, were adopted as the system language of science, all science would become physics. Metaphysics would be discarded as meaningless.” [Ayer: 166] He may be going a bit far here, but his point is sound: physics and the physical world is the same for all of us, and we should pursue knowledge of the realm we all agree to be made up of the same properties.

Should all science be reduced to physics? That would be infinitely more easy, to be sure. But as much as Carnap and materialists may want this, it does not mean we necessarily can. Some science, like behavioral psychology, may require a subjective element. To many, the thought that human beings can be reduced to mere machinery is abhorrent. (But does this make it not true?)


Logical positivism is a school of philosophy that seems to have died out decades ago, but its influence on science should not be disregarded. The basic fact it is trying to assert, with regards to metaphysics, is still sound: there is no sense in arguing over things which cannot be ascertained to be true or false.

Scientists would do well to follow this advice when encountering religion. Science does not disprove God — in fact, as the logical positivists claim, it cannot disprove God. God is not an empirical concept, and is thus outside the realm of science. As they would say, discussion of Him is meaningless. And, although religious devotees may not wish to accept this, it is in some sense true even for them: God is unknowable. To claim we know what He wants is a lie, or misguided. It is best to simply say we do not know and cannot know.

Faith has its role, but faith cannot rely on science and fact for reasons outlined by Schlick and Carnap.


Ayer, A. J., ed. Logical Positivism. Free Press, 1959.

Also try another article under Philosophical
or another one of the writings of Gavin.

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