Consider the hypothesis:

On August 1st 2008 at midnight Greenwich time, a one-foot sphere of chocolate cake spontaneously formed in the center of the Sun; and then, in the natural course of events, this Boltzmann Cake almost instantly dissolved.

I would say that this hypothesis is meaningful and almost certainly false. Not that it is "meaningless". Even though I cannot think of any possible experimental test that would discriminate between its being true, and its being false.

I would say that this hypothesis is meaningful and almost certainly false. Not that it is "meaningless". Even though I cannot think of any possible experimental test that would discriminate between its being true, and its being false.

Well, if you had access to a time machine and some sensing device that could survive the environment of the Sun...

Yeah, I'm a nitpicker. I'm also not as good at picking nits as I might like.

I've an old post - 'Verification and Base Facts' - which shows how a non-verificationist can still capture much of what was most compelling in verificationism.

An idea unconfirmable by experiment is not just probably wrong, but necessarily meaningless.

This depends on whether we're talking about unverifiable-in-practice, or unverifiable-in-principle.

If it's unverifiable-in-principle, there is no distinction between the affirmation and negation of the premise, and the concept is meaningless.

The positivist accusation seems obviously false just based on the whole quantum mechanics series of posts.

Caledonian: There is one exception:

The Kolmogorov complexity of this sentence is exactly 50 bytes in Java bytecode.

Meaningful, but unfalsifiable.

/nitpick

On second thought, that's not right. But you probably understood what I mean. If you happen to make an a conjecture about something like Kolmogorov complexity or the halting problem, and it just happens to be undecidable, it's still either true or false.

Eliezer, you're definitely setting up a straw man here. Of course it's not just you -- pretty much everybody suffers from this particular misunderstanding of logical positivism.

"Untestable" does not mean "untestable by humans using current technology". What it means is untestable, period -- even by (say) a hypothetical being with godlike powers. This is what distinguishes a chocolate cake in the sun from "post-colonial alienation". If a chocolate cake spontaneously formed in the Sun, there would be physical consequences. These consequences would necessarily be detectable to sufficiently advanced beings. We need only imagine a Laplacian calculator, for example.

The feasibility of performing the verification is utterly beside the point, because we're only interested in the meaning of the statement.

Contrast this with "post-colonial alienation". The problem there is not that we lack some technological gadget. Rather, the problem is that no being, not even a god or a Laplacian demon, could verify the statement. In the case of a chocolate cake, you simply present God with a list of ingredients, and tell him/her to look for them in the Sun; but what do you tell God to look for in the works of Shakespeare in order to determine whether there is "post-colonial alienation"?

So this is not a counterexample to logical positivism at all. In fact, you yourself already gave the positivist's reply to this criticism in "Belief in the Implied Invsible". The point is, you're allowed in logical positivism to use the full apparatus of mathematics and logic (and that includes probability theory!) in formulating theories (hence the name logical positivism); verificationism is not a constraint on mathematics.

There are different shades of positivism, and I think at least some positivists are willing to say any statement for which there is a decision procedure even possible in principle for an omnipotent being is meaningful.

Under this interpretation, as Doug S. says, the omnipotent being can travel back in time, withstand the heat of the sun, and check the status of the cake. The omnipotent being could also teleport to the spaceship past the cosmological horizon and see if it's still there or not.

However, an omnipotent being still wouldn't have a decision procedure with which to evaluate whether Shakespeare's works show signs of post-colonial alienation (although closely related questions like whether Shakespeare meant for his plays to reflect alienation could be solved by going back in time and asking him).

This sort of positivism, I think, gets the word "meaningful" exactly right.

The Kolmogorov complexity of this sentence is exactly 50 bytes in Java bytecode.

Meaningful, but unfalsifiable.

You can't make a Java class file that small.

Maybe you mean the difference between the smallest possible executable class file, and one that prints that message will be exactly 50 bytes, given some specified existing standard library? If so, the sentence should probably make that clearer.

Unfortunately, the capabilities of an omnipotent being are themselves not very well defined. Suppose we want to determine whether "The Absolute is an uncle" is meaningful. Well, says the deranged Hegelian arguing the affirmative, of course it is: we just ask our omnipotent being to take a look and see whether the Absolute is an uncle or not.

Butbutbutbut, you say, we can't tell it how to do that, whereas we can tell it how to check whether there's a spaceship past the cosmological horizon. But can we really? I mean, it's not like we know how to make that observation, or we'd be able to make it ourselves. What's the difference between this and checking whether the Absolute is an uncle? "Well, we know what it means to check whether there's a spaceship past the cosmological horizon, but not what it means for the Absolute to be an uncle." Circular argument alert!

It does *feel* like there's a difference that we can use, but trying to formulate it exactly seems to lead to a circular definition.

(No one is really going to defend "The Absolute is an uncle", but there certainly are people prepared to claim that the existence of an afterlife is testable because dead people might discover it, or because God could tell you whether it's there or not; and I don't think any sort of logical positivist would agree.)

I haven't gotten through your whole post yet, but the "postmodernist literature professor" jogged my memory about a trend I've noticed in your post. Postmodernists, and perhaps in particular postmodernist literature professors seem to be a recurring foil. What's going on there? Is a way to break out of that analytically? I sense that as a deeper writer and thinker you'll go beyond cartoonish representations of foils, if nothing more to reflect a deeper understanding of things like postmodernist literature professors as natural phenomena. It seems to me to be more a barrier to knowledge and understanding than an accurate summation of something in our reality (postmodernist literature professors).

No, I still think there's a difference, although the omnipotence suggestion might have been an overly hasty way of explaining it. One side has moving parts, the other is just a big lump of magic.

When a statement is meaningful, we can think of an experiment that confirms it such that the experiment is also built out of meaningful statements. For example, my experiment to confirm the cake-in-the-sun is for a person on August 1 to go to the center of the sun, and see if it tastes delicious. So, IF Y is in the center of the sun, AND IF Y is there on August 1, AND IF Y perceives a sensation of deliciousness, THEN the cake-in-the-sun theory is true.

Most reasonable people will agree that "Today is August 1st" is meaningful, "This is the center of the sun" is meaningful, and "That's delicious!" is meaningful, so from those values we can calculate a meaningful value for "There's a cake in the center of the sun August 1st". If someone didn't believe that "Today is August 1st" is meaningful, we could verify it by saying "IF the calendar says 'August 1', THEN it is August 1st" in which we specify a way of testing that. If someone doesn't even agree that "The calendar says 'August 1'" is meaningful, we reduce it to "IF your sensory experience includes an image of a calendar with the page set to August 1st, THEN the calendar says 'August 1'." In this way, the cake-in-the-sun theory gets reduced to direct sensory experience.

To determine the truth value of the uncle statement, I need to see if the Absolute has an uncle. Mmmkay. So. I'll just go and....hmmmm.

If you admit that direct sensory experience is meaningful, and that statements composed of operations on meaningful statements are also meaningful, then the cake-in-the-sun theory is meaningful and the uncle theory isn't.

(I do believe that questions about the existence of an afterlife are meaningful. If I wake up an hour after dying and find myself in a lake of fire surrounded by red-skinned guys with pointy pitchforks, that's going to concentrate my probability mass on the afterlife question pretty densely to one side.)

It's not clear that you're a verificationist but you're clearly an Empiricist. I think that's problematic. Unless you believe something magical happens at the retina, then there's no more reason to privilege what happens at the retina or in the brain, than there is the wire connecting the dial to the voltmeter. It's all causal linkage. We can use the same standards of reliability for people as we do wires. The sensory periphery is just not particularly interesting.

Is the following assertion meaningless -- "There exists a invisible dragon in my garage, which can't be seen, felt, or sensed by any methods known to man today, or in the future".

"There exists a invisible dragon in my garage, which can't be seen, felt, or sensed by any methods known to man today, or in the future".

This is meaningful and true according to MWI.

Poke, can you expand a little on what you're driving at?

Also, Steven, how on Earth is that statement true under MWI? :)

The dragon is in another world superimposed on ours, one where something improbable happened (some form of genetic engineering?); we will never be able to interact with the dragon in any way, but it's perfectly real, as the people (also invisible to us) in its world can verify.

That dragon isn't in our world, steven. It's not in the garage. The people to which the dragon does exist aren't in our world or our garage, either.

The original claim is meaningless.

I second Hopefully on criticism of the strawman postmodernist. Honestly, I think that academic disciplines, or even schools, where everyone is completely full of it are extremely rare. There are thoughtful, intelligent, and honest people who frame important and fairly novel ideas in the terminology of sociology, academic feminism, Freudianism, behaviorism, even, math-help-us, Jung. Perfect intellectual honest and intelligence among humans are a chimera, and different disciplines aspire to different approximations thereof by establishing different sorts of standards for esteem and for publication.

As a general summary, I would say that the Enlightenment was, to a large extent, a set of proscriptions regarding what types of questions should and should not be asked, argumentative styles should and should not be used, and hand waves are and are not allowed. Some set of standards is necessary for functional discourse under imperfect honesty, and the Enlightenment standards enabled fruitful conversation among people of merely, perhaps, 70th percentile honesty and 96th percentile intelligence, an AMAZING standard that reshaped history. Sadly, each set of standards disables productive discussion of certain subject matter, and places one's beliefs on ultimately unsound foundations, so re-foundation is ultimately necessary. The more dysfunctional academic disciplines are largely those which try to deal, possibly prematurely, with subject matter for which we lack good honesty enforcing protocols, including subject matter foundational to the Enlightenment subject matter, but for individuals in those disciplines insights are indeed possible and low-hanging fruit are even abundant.

I have to agree with komponisto and some others: this post attacks a straw-man version of logical positivism. As komponisto alluded to, you are ignoring the logical in logical positivisim. The logical positivists believed that meaningful statements had to be either verifiable or they had to be logical constructs built up out of verifiable constituents. They held that if A is a meaningful (because verifiable) assertion that something happened, and B is likewise, then A & B is meaningful by virtue of being logically analyzable in terms of the meaning of A and B. They would maintain this even if the events asserted in A and B had disjoint light cones, so that you could never experimentally verify them both. In effect, they subscribed to precisely the view that you endorse when you wrote, "A great many untestable beliefs . . . talk about general concepts already linked to experience, like Suns and chocolate cake, and general frameworks for combining them, like space and time."

Your "general frameworks for combining" do exactly the work that logical positivists did by building statements from verifiable constituents using logical connectives. In particular space and time would be understood by them in logical terms as follows: space and time reduce to geometry via general relativity, and geometry, along with all math, reduces to logic via the logicist program of Russell and Whitehead's Principia Mathematica. See, for example, Hans Reichenbach's _The Philosophy of Space and Time_.

So, even without invoking omnipotent beings to check whether the cake is there, the logical positivist would attribute meaning to that claim in essentially the same way that you do.

Honestly, I think that academic disciplines, or even schools, where everyone is completely full of it are extremely rare.

That isn't the point. Sincere and intelligent people have been coming up with novel ideas on important topics long before scientific methodology was even a sparkle in Galileo's eye.

Most of those ideas were worthless. Most modern ideas are worthless, too. The question is: how good were they at distinguishing the worthy ideas from the worthless ones? The sheer number of recently-discarded fields, much less ideas, should make it clear how well the ancients discerned the gold from the dross.

What's the signal-to-noise ratio? How much care is taken to ensure that people aren't deluding themselves?

michael vassar, Maybe that's a good description of new departments (eg x-studies), but you sound like you think the post-colonial rhetoric is coming out of political science departments rather than English departments.

...and I go on to learn that people in political science departments cite Derida.

Political science is the department where it would be most interesting to know what's going on because it has methodological pluralism while seeming to have a single topic, while, say, English departments seem to have gotten methodological variety out of crisis of topic.

This seems like an excellent example of the application of the Law of the Minimum - admittedly, outside of the specific ecological context it was formulated in, but the general principle is sound.

The resource in least supply will dictate the growth of the population, and the entity that requires the least expended or committed resources while meeting the minimum standards will dominate the population.

Fields that have low standards will be dominated by garbage. Fields with high standards will be dominated by whatever can pass those standards.

What are the standards that determine whether work in a field is valuable? Not from the viewpoint of those within the field, but from a general perspective? Once that's determined, we need only see which fields' requirements best match those standards.

I just finished reading Ayer's "Language, Truth & Logic" last night, and from my understanding of it, I think he'd think that your proposal about the appearance and vanishing of a chocolate cake was a meaningful proposal. He said, for instance, that it would be meaningful and reasonable to posit the appearance of wildflowers on a mountain peak nobody had climbed based on the fact that such wildflowers had been seen on similar mountain peaks nearby, or to propose that there were mountains on the dark side of the moon (before it was possible to empirically verify this). He seemed mostly interested in disqualifying propositions that were /in principle/ unverifiable. Now if you're asserting that this piece of cake came and went /and/ that it's not just going to be really difficult to come up with a single sense-impression that this fact would have some bearing on, but that it is /in principle/ impossible to do so, then he'd probably say you're talking rot.

Your example of a spaceship exiting the range at which you could possibly have any interaction with it is another issue. Ayer deals with the "does this tree continue to be when there's no one about on the quad" question, and says that (if I remember right) since the logical construction "this tree" is composed of both actual and hypothetical sense experiences, there's no reason why you have to imagine it vanishing when those sense experiences aren't immediately occurring. Even given this, though, I'm not sure if Ayer would call your spaceship meaningless or merely improbable, since its hypotheticals would all seem to be logical impossibilities.

The classic objection to logical positivism is that it is incoherent: If statements which are not testable are meaningless, then the statement "Statements which are not testable are meaningless" is meaningless. For those of you defending logical positivism of any sort, how do you deal with this criticism? Is there even a way to test the central tenet of logical positivism in principle?

If statements which are not testable are meaningless, then the statement "Statements which are not testable are meaningless" is meaningless.

Only if "Statements which are not testable are meaningless" isn't testable.

Can you show it to be untestable? Or is there a way you might check?

If all you are worried about is in-principle verification, then, so the argument goes, the way to check is to see if there is any empirical content to "statements which are not testable are meaningless." What is there in the world that we would see if that statement is true?

There are three categories -- "meaningful," "meaningless," and "tautological" statements -- at least in Ayer's categorization. "Statements which are not testable are meaningless or tautological" would be an example of a tautology: just a definition of terms.

Because if you /could/ test the statement to see if it were true (not absolutely true, but, per Ayer, "probable"), you'd conduct an experiment where you took a sample of statements, tried to come up with tests (ways in which they refer to sense experiences that would serve to verify or disprove them), and then saw which ones were or were not meaningful. But in Ayer's framework, meaningfulness is defined as referring to sense experiences that would serve to verify or disprove, so it's circular, thus tautological, which isn't a term of abuse in Ayer's categorization the way meaninglessness is. He thinks that philosophers deal in tautologies all the time -- constructively! -- and that meaningful statements are more in the domain of science anyway.

he way to check is to see if there is any empirical content

OR, you see what logical content it has. We don't need to locate an immovable object or an irresistible force, much less try to combine them, to answer the question of what happens when they meet.