
Why falsificationism is false - viburnum
https://necpluribusimpar.net/why-falsificationism-is-false/
======
noego
The author makes some good points, but does not propose his own criteria for
what distinguishes a good theory from a bad theory, which seems like a cop-out
to be frank.

I imagine a big appeal of falsifiability in its early days, stemmed from its
opposition to religious dogma. Imagine dealing with someone whose answer to
every question comes back to God. _" Why did the patient die?"_ _" Because God
decreed it."_ Talking about germ-theory must have been a massive improvement
over theology, hence why ideas like falsifiability must have arisen to provoke
people to think in more critical ways.

My own standard for evaluating theories comes down to the following: The
_simplest_ explanation that best _fits existing data_ , and makes _useful
predictions_ for the future.

 _" Simplest"_ because we need to prevent overfitting.

 _" Fits existing data"_ because the whole point of a theory is to explain
what we see around us.

And " _useful predictions_ " because it will actually provide practical
benefit to us. As opposed to a theory like _" God decreed it"_, which may be
extremely simple and error-free, but provides us with no practical benefit at
all.

As I see it, falsifiability is a side-effect of the second and third
requirements. If a theory is making useful predictions, we might as well check
to see if it's accurate. And if it's not, there's no point in holding on to a
theory that's making faulty predictions. Falsifiability, in this perspective,
isn't a requirement in and of itself - it's a natural consequence of the
requirement that theories be useful and fit any data at hand.

~~~
thethirdone
> The simplest explanation that best fits existing data, and makes useful
> predictions for the future.

My main issue with that definition is what makes it a useful prediction. Does
a theory (for particle physics) that predicts the Higgs Boson more useful than
one that didn't? If not, then before we collected the data to reject other
theories they all would have been equal.

I would rather suggest that the properties of a good theory are best fitting
existing data and having specific predictions for future measurements.

> Falsifiability, in this perspective, isn't a requirement in and of itself -
> it's a natural consequence of the requirement that theories be useful.

If you are of the opinion that any good theory is falsifiable (in the sense
described in the article), then presumably you disagree with the rejection of
falsifiability in the article. Where would you say the error in logic in the
article is?

~~~
gliop
A useful prediction is a prediction that matches experimental results.

~~~
thethirdone
You can't possibly know what will match experimental results in the future so
that doesn't help determine good theories in the present.

And I would say that Newtonian gravity was a useful theory despite not
matching experimental currently because when it was the best it mostly
explained observations.

~~~
chii
> Newtonian gravity was a useful theory despite not matching experiment

"Useful" in this context means useful for a future theory or experimentation,
not utility. Newtonian theory certainly predicted many results, and all of
them were useful in the above sense. A prediction doesn't have to exactly
match observations to be useful, but that the theory produces a prediction
which _could_ be tested against.

Even flat-earth theory makes useful predictions - albeit already proven false
as time and time again, it predicts the wrong results.

What isn't useful is an unfalsifiable theory, which means the predictions it
makes is not able to be tested, or the results of such a test could be
construed to match if you squint a bit. A theory like creationism, for
example.

~~~
thethirdone
I am a bit confused by your comment. I'm not sure if you agree with gliop or
not. I am simply saying that Newtonian gravity is useful (in pretty much any
sense) and that it did not match all experiments. Particularly in the orbit of
Mercury could not be explained.

> Even flat-earth theory makes useful predictions - albeit already proven
> false as time and time again, it predicts the wrong results.

I definitely agree usefulness is independent of fitting experimental data.
gliop would seem to say flat earth theories are not useful.

~~~
noego
I don't think the value of a theory can be evaluated in isolation. It can only
be evaluated relative to its competition. During its time, Newtonian gravity,
even if it didn't perfectly fit all data, was still superior to its
competition on an aggregate of the 3 criteria mentioned. Only once Einstein's
theories were put forward, were we able to replace Newtonian gravity with a
superior alternative.

------
outlace
This article attacks falfsificationism in part on the basis that scientists
don’t seem to actually behave according to “naive falsficationism” in which
you supposedly should immediately throw out a theory as soon as you get some
conflicting empirical data.

The article notes that collecting empirical data to falsify a theory depends
on auxiliary theories (eg testing the idea that smoke causes cancer in rats
depends on our ability to precisely define and identify when cancer is
present) and so most scientists will question these auxiliaries rather than
the main theory if conflicting data comes out. This is presented as evidence
that scientists don’t actually practice falsficationism.

This whole discussion completely ignores uncertainty and the fact that
theories describe not only relationships between variables but also involve
parameters that need to be estimated.

If I fill a rat cage with smoke and the rats don’t get cancer, I don’t
immediately assume all previous studies were wrong. This isn’t ignoring my
duty to falsify, it’s realizing that the theory that smoking causes cancer
describes a causal relationship between variables (smoking -> cancer) it also
implicitly or explicitly depends on parameters (in this case, how much and how
long a rat must be exposed to smoke to cause cancer at some incidence rate).
Given that many other studies found the causal relationship, it is more likely
that my experiment messed up the parameters of the causal model (eg I didn’t
administer smoke long enough) rather than messed up the causal relationship.
And parameter estimation is subject to uncertainty.

Now if I’m absolutely sure I’m getting all my model parameters correct, and I
can only be confident if other people get the same results. Then I’m moving
toward falsifying the theory.

The point is that science involves positing theories, and theories are
descriptions of causal relationships and generally involve parameters. Much of
science is just estimating model parameters given that we assume some model to
be tentatively true. You assume your model to be tentatively true, eg smoking
causes cancer, now you need to estimate the effect size which is a parameter
problem.

------
lisper
This article attacks a straw man. Being falsifiable is necessary but it is
_not_ sufficient to be considered a scientific hypothesis. Such a hypothesis
also, and more importantly, has to provide a better _explanation_ of some
phenomenon than the current best theory. Experimental evidence is only brought
to bear to decide among plausible alternative theories after the vast majority
of candidate theories have been eliminated for not providing good
explanations.

It's easy to see that this must be true because we can only ever have a finite
amount of data, and that will always be consistent with an infinite number of
falsifiable theories (c.f. Russell's teapot). So data cannot possibly help us
choose from among those.

~~~
logicchop
Popper heavily criticizes the value of explanation. He gives examples of
really great "explanations" that have almost zero empirical value (things like
psychoanalysis). Hard to see how it could be a "straw man."

~~~
Animats
"Science is prediction, not explanation." \- Fred Hoyle.

~~~
lorriman
I heard Fred Hoyle when he came to lecture at my school in the 80s (a
prestigious, rich boys school). It was one of the few places willing to give
him the time as his views were vaguely in line with Christian creationism
though he was an atheist, ironically. It was doubly ironic in that the school
was Catholic and Catholic Christianity is not biblically literalist. In fact
the inventor of the Big Bang theory eventually became a Catholic priest.
hahaha!

------
whatshisface
If there's no conceivable experiment that could contradict your claim then
it's meaningless. Just because there might be other ways for a claim to be
vacuous doesn't mean the necessary condition above doesn't hold.

~~~
smallnamespace
There may be some difficulties with the criterion that you just laid out, one
practical and another logical:

1\. 'Conceivable experiment' is a changing definition, since the realm of what
humans can conceive is always expanding with the growth of technology and
knowledge. If we had been around 2000+ years ago, would you have considered
Democritus's atomic theory to be meaningless, given the lack of any
conceivable path to test it at the time?

Either you have to take quite an expansive view of what is 'conceivable', or
admit that 'meaningless' here refers more to practical difficulties that may
be temporary, rather than anything inherent in a particular claim.

2\. If we turn your statement back on itself, statements about meaning are
also statements about the world (after all, what is 'meaning' if it doesn't
involve what humans think and believe?). Is your statement that 'only
falsifiable claims are meaningful' itself falsifiable? If so, what sort of
experiment would you set up to test it?

~~~
whatshisface
> _would you have considered Democritus 's atomic theory to be meaningless,
> given the lack of any conceivable path to test it at the time?_

Strictly speaking Democritus's atomic theory is still untestable today because
it doesn't include the actual scale of the atoms. For all we know the
apparently continuous quantum fields are themselves made of "atoms" (in his
sense, not the modern meaning of the word atom). If he had said "things will
get clearly atom-y around a nanometer" then it would have been at least
conceivable that someone could eventually look that closely.

> _you have to take quite an expansive view of what is 'conceivable'_

That's right, I was laying down a very liberal criteria (and saying that it
was a necessary but insufficient condition).

> _If so, what sort of experiment would you set up to test it?_

That's kind of like asking what sort of experiment could disprove the law of
the excluded middle: not an unreasonable question, but the answer is going to
sound pretty silly. To test my claim, you could iterate though every claim
about the universe, checking to see if it simultaneously could not contradict
with any observation, and yet predicted what you would observe. Good luck
actually doing it; but it does technically meet my criterion.

~~~
smallnamespace
> That's right, I was laying down a very liberal criteria

> but the answer is going to sound pretty silly.

Yes, I was trying to illustrate that the line between 'science' and
'metaphysics' is necessarily a blurry one, and the choice of (and
justification for) where to draw it itself lies in the realm of metaphysics.

The broader the universe of claims you admit as scientific, the more
'testability' and 'falsifiability' lie closer to the realm of theory. However,
even theories (and paradigms) that can't be directly placed on the
experimenter's bench today can point towards fruitful lines of investigation.

On the flip side, we can't but to make metaphysical (and therefore non-
scientific) claims and hold them as true, despite our best efforts ... the
strong version of 'scientism' (that only scientific claims can have meaning)
is a self-defeating one.

------
thethirdone
> This means that a theory is never falsifiable simpliciter, but only relative
> to a set of background assumptions. Therefore, if we say that a theory is
> only scientific if it’s falsifiable, then it follows that no theory, not
> even a theory as successful as Newton’s law of universal gravitation, is
> scientific. Of course, this is absurd, so falsificationism is false.

You can consider the union of the theory and background assumptions to be a
single theory. The premises do not imply that no theory is scientific.

An analogy to mathematics is pretty apt. The Riemann hypothesis (RH) is
falsifiable in the crude sense described, but cannot be proven or disproven
without an axiomatic basis. If you were able to derive a contradiction from RH
and some other accepted theorems, you would think that falsifies RH. However,
if you wanted a more concrete picture of what was proved, you might reduce the
other theorems to Zermelo–Fraenkel set theory (ZF) so you have the result that
RH + ZF is inconsistent/false. Maybe in some other axiomatization RH is true,
but the general community accepts ZF so that means RH + ZF is false
effectively means RH is false.

I do agree with some of the sentiment of the article. There should be thought
about how to actually test what we say we are testing (not having a reliance
on background assumptions) and to accept negative results rather than just
find something to blame.

------
nerdponx
What is the point of this article? The content is interesting: falsification
is more complicated than it seems at first, and scientists don't practice
philosophically-pure falsificationism. But it's wrapped up in some kind of
finger-pointing "the emperor has no clothes!" type of exposé format that
doesn't make sense and doesn't lead to a satisfying conclusion.

~~~
dang
The article explains clearly and at length why the author wanted to write it.
But the best thing you say here is "The content is interesting". That's why it
belongs on HN!

[https://news.ycombinator.com/newsguidelines.html](https://news.ycombinator.com/newsguidelines.html)

~~~
nerdponx
Sorry I was unclear. My comments were meant for the author, not the poster.

~~~
dang
Yes, and he goes into that at length in the article. The HN thing was just my
addition; shop talk basically.

------
viburnum
Well that is definitely not the title I submitted.

~~~
dang
The site guidelines call for using the original title unless it is misleading
or linkbait
([https://news.ycombinator.com/newsguidelines.html](https://news.ycombinator.com/newsguidelines.html)).
Judging by the first couple of comments that appeared here, the title is
baity, because it was generating shallow reactions—to the top-level dramatic
claim, rather than to the rich content in the article, such as its final
paragraph.

When the comments in a thread are generated from the most-obvious, already-
familiar information in an article—which often shows up in the title—than we
get a discussion of people reciting things they already know or believe (not
interesting!), instead of a learning process (much more interesting).

I changed the title to "There are strong arguments against falsificationism",
which is a phrase from the article body. (When we change titles, we always
look for representative language in the article itself.) A couple minutes
later, I wasn't sure, so reverted it. This is a bit of an edge case. To some
extent, what to do with the title depends on which direction the thread takes:
shallow "I know better" dismissals? or thoughtful responses to the less
obvious?

