What is "falsifiability" exactly?

[ccdan]

I have noticed that this term gets thrown around quite often when people debate what's "scientific" and what is not.

What I have NOT found is a definition or explanation of "falsifiability" that is unambiguous, coherent and logical! 

Apparently it's an alleged "property" of a theory or hypothesis, which for some mysterious reason makes it "scientific" (whatever that might mean - I'll get back to that later) 

So we need a "test" which could tell us whether a theory/hypothesis is "falsifiable" or not. In the context of science any such a "test" should be rigorously and unambiguously defined.

The problem is, the only things I found are ambiguous and nonsensical ramblings made by people who seem very unfamiliar with the clarity, rigor and logical soundness that actual science requires. And I haven't even touched on the issue of how such a "test" would prove that something is "scientific" and what that would really mean.

Let's explore a few examples ... first, wikipedia:

Quote

A statement, hypothesis, or theory has falsifiability (or is falsifiable) if it is contradicted by a basic statement, which, in an eventual successful or failed falsification, must respectively correspond to a true or hypothetical observation.^[

 

So we have:

"basic statement" - what does it mean? how does it differ from non-"basic statements"? do you just have to "say something"? 

"successful or failed falsification" - a theory is falsifiabile if [something], which, in eventual successful or failed falsification [some other stuff] - what is the meaning of falsification here, as it sounds like a circular statement

"must respectively correspond to a true or hypothetical observation" - what's the meaning of "hypothetical observation"? it kinda sounds like oxymoron! are imaginary things are ok? unicorns? aliens? or just scenarios that are imaginary but seem plausible due to similar actual facts that exists or perhaps laws of physics? 

OK, let's now explore the concrete example... from the same wikipedia:

Quote

For example, the claim "all swans are white and have always been white" is falsifiable since it is contradicted by this basic statement: "In 1697, during the Dutch explorer Willem de Vlamingh expedition, there were black swans on the shore of the Swan River in Australia", which in this case is a true observation

1. what if that "basic statement" were not a "true observation" but some imaginary stuff?

2. how about this one: "all swans have two eyes" ... good luck finding a three eyed swan!

OK,  now let's try to falsify one popular "theory": "The earth is flat!" - well, this is contradicted by many statements and experiments that back them! So "the earth is flat" is a scientific theory according to Popper! WOW! How does it help us in separating non-scientific stuff from scientific stuff?

We can even try to formulate theories related to imaginary friends: "In every room in every building on earth, there's a green unicorn!" Finding just one room without an unicorn would make the theory "scientific". You can replace unicorns with angels, gods or whatever. 

Then there's the nonsense that a theory can only be "disproved" and never "proved" - which is hugely wrong and nonsensical(you might get to "disprove" an infinity of things and won't be able to reach any conclusion)! Actually the whole story about "falsifiability" comes from this philosophical idea of Popper that "nothing is certain" and theories can only be shown to be false. Besides being wrong, is completely unhelpful, as that's not the way we use science to our benefit.

I'll stop here for now. 

[koti]

10 minutes ago, ccdan said:

I have noticed that this term gets thrown around quite often when people debate what's "scientific" and what is not.

What I have NOT found is a definition or explanation of "falsifiability" that is unambiguous, coherent and logical! 

Apparently it's an alleged "property" of a theory or hypothesis, which for some mysterious reason makes it "scientific" (whatever that might mean - I'll get back to that later) 

So we need a "test" which could tell us whether a theory/hypothesis is "falsifiable" or not. In the context of science any such a "test" should be rigorously and unambiguously defined.

The problem is, the only things I found are ambiguous and nonsensical ramblings made by people who seem very unfamiliar with the clarity, rigor and logical soundness that actual science requires. And I haven't even touched on the issue of how such a "test" would prove that something is "scientific" and what that would really mean.

Let's explore a few examples ... first, wikipedia:

 

So we have:

"basic statement" - what does it mean? how does it differ from non-"basic statements"? do you just have to "say something"? 

"successful or failed falsification" - a theory is falsifiabile if [something], which, in eventual successful or failed falsification [some other stuff] - what is the meaning of falsification here, as it sounds like a circular statement

"must respectively correspond to a true or hypothetical observation" - what's the meaning of "hypothetical observation"? it kinda sounds like oxymoron! are imaginary things are ok? unicorns? aliens? or just scenarios that are imaginary but seem plausible due to similar actual facts that exists or perhaps laws of physics? 

OK, let's now explore the concrete example... from the same wikipedia:

1. what if that "basic statement" were not a "true observation" but some imaginary stuff?

2. how about this one: "all swans have two eyes" ... good luck finding a three eyed swan!

OK,  now let's try to falsify one popular "theory": "The earth is flat!" - well, this is contradicted by many statements and experiments that back them! So "the earth is flat" is a scientific theory according to Popper! WOW! How does it help us in separating non-scientific stuff from scientific stuff?

We can even try to formulate theories related to imaginary friends: "In every room in every building on earth, there's a green unicorn!" Finding just one room without an unicorn would make the theory "scientific". You can replace unicorns with angels, gods or whatever. 

Then there's the nonsense that a theory can only be "disproved" and never "proved" - which is hugely wrong and nonsensical(you might get to "disprove" an infinity of things and won't be able to reach any conclusion)! Actually the whole story about "falsifiability" comes from this philosophical idea of Popper that "nothing is certain" and theories can only be shown to be false. Besides being wrong, is completely unhelpful, as that's not the way we use science to our benefit.

I'll stop here for now. 

So what better alternative to the scientific method would you propose?

[Phi for All]

17 minutes ago, ccdan said:

So we need a "test" which could tell us whether a theory/hypothesis is "falsifiable" or not. In the context of science any such a "test" should be rigorously and unambiguously defined.

It's pretty simple, really. Can you think of a way to show something is false? Then it's falsifiable. 

18 minutes ago, ccdan said:

2. how about this one: "all swans have two eyes" ... good luck finding a three eyed swan!

But that's a great example. Finding a three-eyed swan is EXACTLY what would show "all swans have two eyes" to be a false statement.

As a counter example, arguing that the Christian God exists is NOT falsifiable. Being unobservable, there's no way to perform adequate tests. There's no way to form a prediction based on observed behavior. Almost by definition, this god isn't going to show itself because that would destroy the reason behind the faith of its followers. 

24 minutes ago, ccdan said:

Then there's the nonsense that a theory can only be "disproved" and never "proved"

Why is it nonsense? A single black swan is enough to disprove a statement like "all swans are white". But if I say "all swans are black or white", I can't prove that, not even if I check every living swan. I'd have to check every swan there ever was, or ever will be, and I'd have to be sure swans didn't live on any other planet in the universe as well. 

This is the basis for theory, the idea that we can only accumulate evidence in support rather than "proving" an idea. It's what keeps us searching for the most supported explanations, rather than answers we decide on and never go back to check.

[Strange]

50 minutes ago, ccdan said:

from the same wikipedia:

For someone banging on about clarity etc, I’m rather surprised you haven’t provided a reference. 

I agree that the first bit of text you quote appears pretty bad. But as I don’t know where it is from, I can’t say much more. 

52 minutes ago, ccdan said:

OK,  now let's try to falsify one popular "theory": "The earth is flat!" - well, this is contradicted by many statements and experiments that back them! So "the earth is flat" is a scientific theory according to Popper! WOW! How does it help us in separating non-scientific stuff from scientific stuff?

That is a hypothesis not a theory. It is falsifiable because we can specify ways of testing it. As it happens, these show that the hypothesis is false. Which it is why it is not a theory. 

54 minutes ago, ccdan said:

We can even try to formulate theories related to imaginary friends: "In every room in every building on earth, there's a green unicorn!" Finding just one room without an unicorn would make the theory "scientific". You can replace unicorns with angels, gods or whatever. 

You seem to confusing “falsified” with “falsifiable”

56 minutes ago, ccdan said:

Then there's the nonsense that a theory can only be "disproved" and never "proved" - which is hugely wrong and nonsensical(you might get to "disprove" an infinity of things and won't be able to reach any conclusion)!

The idea here is that you only need one example to disprove something (eg your room without a green unicorn) but it is much harder to prove something. Let’s say you have looked in every room in your house and, yes, there is a green unicorn there (obviously, this is just to explain the point).

Then you check every room in every building in your town. Yep, the hypothesis still holds. You check every room in your country and then on the planet. Still no rooms without green unicorns. But by now, thousands of new buildings have gone up; they all need to be checked. And can you be certain that there weren’t some secret or hidden rooms you missed. And what about buildings on other planets (if they exist). 

It is usually impossible or impractical to test something exhaustively. So science more often relies on finding a counter-example, rather than trying to confirm every possible case. 

1 hour ago, ccdan said:

I'll stop here for now. 

Good. I think you need to go and chill out 

[ccdan]

1 hour ago, koti said:

So what better alternative to the scientific method would you propose?

"falsifiability" has absolutely nothing to do with the scientific method. 

[Strange]

7 minutes ago, ccdan said:

"falsifiability" has absolutely nothing to do with the scientific method. 

How about this:

Quote

 The process of the scientific method involves making conjectures (hypotheses), deriving predictions from them as logical consequences, and then carrying out experiments or empirical observations based on those predictions.^[5][6] A hypothesis is a conjecture, based on knowledge obtained while seeking answers to the question. The hypothesis might be very specific, or it might be broad. Scientists then test hypotheses by conducting experiments or studies. A scientific hypothesis must be falsifiable, implying that it is possible to identify a possible outcome of an experiment or observation that conflicts with predictions deduced from the hypothesis; otherwise, the hypothesis cannot be meaningfully tested

From: https://en.wikipedia.org/wiki/Scientific_method

[Sensei]

1 hour ago, ccdan said:

We can even try to formulate theories related to imaginary friends: "In every room in every building on earth, there's a green unicorn!"

The key word here is "every"...

1 hour ago, ccdan said:

Finding just one room without an unicorn would make the theory "scientific".

No, it would not. It would show that "In every room in every building on earth, there's a green unicorn!" is false statement.

[ccdan]

12 minutes ago, Strange said:

How about this:

From: https://en.wikipedia.org/wiki/Scientific_method

It''s wrong. As is the article on "falsifiability"

No one does actual science by trying to "disprove" theories, hypotheses and so on. 

1 hour ago, Phi for All said:

But that's a great example. Finding a three-eyed swan is EXACTLY what would show "all swans have two eyes" to be a false statement.

The only problem being, that, until you find a three eyed swan, the statement "all swans have two eyes" is non-falsifiable, that is, non-scientific - according to the Popperian theory you're subscribing to. 

[Phi for All]

27 minutes ago, ccdan said:

The only problem being, that, until you find a three eyed swan, the statement "all swans have two eyes" is non-falsifiable, that is, non-scientific - according to the Popperian theory you're subscribing to. 

This is where your mistake lies. False, falsify, and falsifiable are three different concepts in science. All swans have two eyes is a false statement (I found a picture of a one-eyed swan). The picture falsified the statement "all swans have two eyes". The fact that finding swans with more or less than two eyes would make the statement "all swans have two eyes" false means the statement is falsifiable. 

All swans have two eyes is a statement that can be checked to see if it's false (making it falsifiable), but we can't do any checks to be certain it's true. 

[ccdan]

7 minutes ago, Phi for All said:

This is where your mistake lies. False, falsify, and falsifiable are three different concepts in science. All swans have two eyes is a false statement (I found a picture of a one-eyed swan). The picture falsified the statement "all swans have two eyes". The fact that finding swans with more or less than two eyes would make the statement "all swans have two eyes" false means the statement is falsifiable. 

All swans have two eyes is a statement that can be checked to see if it's false (making it falsifiable), but we can't do any checks to be certain it's true. 

Don't put things in my mouth... here's the original text from wiki:

Quote

For example, the claim "all swans are white and have always been white" is falsifiable since it is contradicted by this basic statement: "In 1697, during the Dutch explorer Willem de Vlamingh expedition, there were black swans on the shore of the Swan River in Australia", which in this case is a true observation

My statement is basically identical, I just replaced color with the number of eyes. "since" = that's why it's falsifiable, otherwise it wouldn't be

Edited August 21, 2019 by ccdan

[Strange]

38 minutes ago, ccdan said:

The only problem being, that, until you find a three eyed swan, the statement "all swans have two eyes" is non-falsifiable, that is, non-scientific - according to the Popperian theory you're subscribing to. 

The fact that you can count swan’s eyes is what makes it falsifiable. As it is impossible to check every Sean that ever lived or will live, all you can do is hope to find a swan with one or three eyes to disprove the hypothesis. 

42 minutes ago, ccdan said:

It''s wrong. As is the article on "falsifiability"

No one does actual science by trying to "disprove" theories, hypotheses and so on. 

Says the guy who doesn’t even know the difference between “falsify” and “falsifiable”.

 

[ccdan]

1 hour ago, Sensei said:

The key word here is "every"...

No, it would not. It would show that "In every room in every building on earth, there's a green unicorn!" is false statement.

It's irrelevant the so called keyword.

every room in every building = all swans 

"there's a green unicorn in every room" = property of the room(it has an unicorn), equivalent to the color of the swan

If you find a single room without unicorn, the property of the room is changed, equivalent to finding a swan of a different color

14 minutes ago, Strange said:

The fact that you can count swan’s eyes is what makes it falsifiable. As it is impossible to check every Sean that ever lived or will live, all you can do is hope to find a swan with one or three eyes to disprove the hypothesis. 

That's completely nonsensical. Counting swan's eyes is the same as seeing swan's color. The number of eyes is just a property of the swan, the same way color is. By that logic, seeing the color of a swan would make the statement "all swans are white" falsifiable. 

Edited August 21, 2019 by ccdan

[Sensei]

6 minutes ago, ccdan said:

By that logic, seeing the color of a swan would make the statement "all swans are white" falsifiable. 

But "all swans are white" is false statement. Some swans are not white.

https://en.wikipedia.org/wiki/Black_swan

The key word in this statement is "all". If statement would be "majority of swans are white", finding swan with different color would not contradict statement.

 

[ccdan]

10 minutes ago, Sensei said:

But "all swans are white" is false statement. Some swans are not white.

 

You don't seem to be paying much attention to what I'm saying. I already told you the wiki article claims that "Some swans are not white" is what make the statement FALSIFIABLE! 

Quote

"all swans are white and have always been white" is falsifiable since it is contradicted by this basic statement: "In 1697, during the Dutch explorer Willem de Vlamingh expedition, there were black swans on the shore of the Swan River in Australia", which in this case is a true observation

 

Edited August 21, 2019 by ccdan

[uncool]

3 hours ago, ccdan said:

OK,  now let's try to falsify one popular "theory": "The earth is flat!" - well, this is contradicted by many statements and experiments that back them! So "the earth is flat" is a scientific theory according to Popper! WOW! How does it help us in separating non-scientific stuff from scientific stuff?

It is a scientific statement, which (as you have said) has been falsified. In this terminology, "scientific" does not mean "confirmed". It's approximately equivalent to saying that a sentence is grammatically correct - the content may be true or false, but it satisfies certain rules about the sentence itself.

[Strange]

1 hour ago, ccdan said:

is. By that logic, seeing the color of a swan would make the statement "all swans are white" falsifiable. 

Yep. That is exactly what makes the sentence falsifiable. (Even before any non-white swans had been seen.)

I’m not sure what you are struggling with. If you want to test a statement about the colour of swans then the minimum requirement is to see the colour of swans. (Testable = falsifiable)

25 minutes ago, uncool said:

It is a scientific statement, which (as you have said) has been falsified. In this terminology, "scientific" does not mean "confirmed". It's approximately equivalent to saying that a sentence is grammatically correct - the content may be true or false, but it satisfies certain rules about the sentence itself.

Nice example. This does remind me of when I was studying logic and some of the other students could not get theirs round the concept that an argument could be logically sound but still not be true. 

34 minutes ago, ccdan said:

You don't seem to be paying much attention to what I'm saying. I already told you the wiki article claims that "Some swans are not white" is what make the statement FALSIFIABLE! 

 

That article is just badly worded. Get over it. 

I note you are still not able to provide a reference. 

[Strange]

The bit about swans comes from this page: https://en.wikipedia.org/wiki/Falsifiability

It is an excellent example of why one should not rely on Wikipedia as a primary source. There is some quite good discussion on the Talk page, some of which clarifies what is there. (But I haven't read enough of it to be sure I would trust it, either.)

 

[swansont]

17 hours ago, ccdan said:

OK,  now let's try to falsify one popular "theory": "The earth is flat!" - well, this is contradicted by many statements and experiments that back them! So "the earth is flat" is a scientific theory according to Popper! WOW! How does it help us in separating non-scientific stuff from scientific stuff?

You can make a falsifiable claim and not have it be a scientific theory. Falsifiability is one element — a necessary but insufficient condition. "Elvis is still alive" is a falsifiable claim. It's not a theory.

 

Theories have to make specific enough predictions that they can be shown to be wrong. If you have competing theories, you need to be able to do an experiment where they will give conflicting predictions, so one can be eliminated.

[LazyLemonLucas]

On 8/21/2019 at 9:56 AM, ccdan said:

Then there's the nonsense that a theory can only be "disproved" and never "proved" - which is hugely wrong and nonsensical(you might get to "disprove" an infinity of things and won't be able to reach any conclusion)! Actually the whole story about "falsifiability" comes from this philosophical idea of Popper that "nothing is certain" and theories can only be shown to be false. Besides being wrong, is completely unhelpful, as that's not the way we use science to our benefit.

I'll stop here for now. 

Karl Popper read about Sigmund Freud's theories and listened to Albert Einstein's lectures which helped him formulate the theory that makes "pseudoscience" (as he coined it) and "science" distinct.

What he realized is that Sigmund Freud could warp evidence to conform to his theory. For example: Sigmund Freud could explain how a child might feel lonely by explaining that they were hugged too little as a child (lack of affection; induces alienation to affection) or being hugged too much as a child (affection becomes a normal occurence it is taken for granted). Sigmund Freud seeked to prove his theory which ultimately leads him to cognitive dissonance and bias--something unscientific.

Albert Einstein did not do what Sigmund Freud did. What Albert Einstein did sounds counterproductive, but he seeked to disprove his theory. The solar eclipse of 1919 was heavily watched by Albert Einstein as the way light would travel to Earth would've disproven the Theory of Relativity, but as we all know, it becomes the most well-known scientific theory today. (The solar eclipse proved the Theory of Relativity as Einstein observed how the light warps or bends)

What seperated Sigmund Freud and Albert Einstein was unorthodox and seemingly contradicting, but we can never trust how we "feel" but rather what we "know". We know that theories that seek to disprove are scientific because they do not have the bias that a theory that would seek to prove. It sounds weird, I know, but Karl Popper thought that seeking to disprove eliminates more bias than seeking to prove ever would. 

In his eyes, every "wrong" theory that we assume gets us that more closer to the truth, because we have just crossed off one wrong idea to be replaced with a right one.

[Ken Fabian]

On 6/6/2022 at 12:39 PM, LazyLemonLucas said:

What Albert Einstein did sounds counterproductive, but he seeked to disprove his theory.

I thought Einstein sought empirical evidence that his theory was correct; if it were true the bending of light by gravity would be demonstrated. If it were not correct that would be demonstrated too, but I don't think it was proposed as an attempt to disprove. Other people probably did see it like that. It works as Falsifiable in Popper's terms but not by any intent to conform to Popper's terms; Popper's ideas didn't get published until a couple of decades after the observations that showed Einstein was correct.

Edited June 8, 2022 by Ken Fabian

[exchemist]

On 6/6/2022 at 4:39 AM, LazyLemonLucas said:

Karl Popper read about Sigmund Freud's theories and listened to Albert Einstein's lectures which helped him formulate the theory that makes "pseudoscience" (as he coined it) and "science" distinct.

What he realized is that Sigmund Freud could warp evidence to conform to his theory. For example: Sigmund Freud could explain how a child might feel lonely by explaining that they were hugged too little as a child (lack of affection; induces alienation to affection) or being hugged too much as a child (affection becomes a normal occurence it is taken for granted). Sigmund Freud seeked to prove his theory which ultimately leads him to cognitive dissonance and bias--something unscientific.

Albert Einstein did not do what Sigmund Freud did. What Albert Einstein did sounds counterproductive, but he seeked to disprove his theory. The solar eclipse of 1919 was heavily watched by Albert Einstein as the way light would travel to Earth would've disproven the Theory of Relativity, but as we all know, it becomes the most well-known scientific theory today. (The solar eclipse proved the Theory of Relativity as Einstein observed how the light warps or bends)

What seperated Sigmund Freud and Albert Einstein was unorthodox and seemingly contradicting, but we can never trust how we "feel" but rather what we "know". We know that theories that seek to disprove are scientific because they do not have the bias that a theory that would seek to prove. It sounds weird, I know, but Karl Popper thought that seeking to disprove eliminates more bias than seeking to prove ever would. 

In his eyes, every "wrong" theory that we assume gets us that more closer to the truth, because we have just crossed off one wrong idea to be replaced with a right one.

I’m with @Ken Fabian on this. Einstein et al weren’t trying to disprove the theory. They wanted to test it to see if it gave correct predictions or not.

Falsifiability does not mean you have to try to falsify a theory, just that for a theory to be science it must be testable in a way that is capable of showing it false if its predictions are not borne out by observation.

[LazyLemonLucas]

3 hours ago, exchemist said:

I’m with @Ken Fabian on this. Einstein et al weren’t trying to disprove the theory. They wanted to test it to see if it gave correct predictions or not.

Falsifiability does not mean you have to try to falsify a theory, just that for a theory to be science it must be testable in a way that is capable of showing it false if its predictions are not borne out by observation.

Apologies. I mistook Einstein's theories in which he had no preconceived notions as an attempt to disprove his theory. Though I can't say the same with Freud who did have preconceived notions. 

[exchemist]

7 hours ago, LazyLemonLucas said:

Apologies. I mistook Einstein's theories in which he had no preconceived notions as an attempt to disprove his theory. Though I can't say the same with Freud who did have preconceived notions. 

Yes I think the problem with Freud is that his theories didn’t really make testable predictions. He could theorise about the reasons for something after the event, but he couldn’t find a child that not been hugged, say, and correctly predict it’s behaviour without knowing it beforehand. It all seems to be ex post facto explanation.

Mind you, I sometimes get a bit queasy about certain rationalisations of behaviour in chemistry, for similar reasons. For instance, One can read qualitative explanations of why Hg is a liquid at r.t.p., but I’m not sure any theory is capable of predicting that outcome exactly. With very complex systems in science, one can get a fair amount of rationalisation after the event.

[jimmydasaint]

I just want to address the OP. ccdan referred to Popper and was struggling to find relevant data where a hypothesis was falsified in the Popperian hypothetico-deductive method.

Firstly, do you believe that there is some Objective Truth about phenomena or objects? Something that is independent of the subject and subjective bias? 

IIRC Popper believed that an Objective Truth could be reached through a deductive scientific method because induction was not enough. So a hypothesis is made, tested experimentally and then, if proved false, is modified and re-tested until it is close to an Objective Truth as possible.

I think Plato already indicated a sense of doubt about the reliability of observation and even getting close to an Objective Truth is valid science in my opinion.

My sense of ambivalence about the subject arises because I have seldom seen scientists go out of their way to falsify hypotheses. Quite the opposite. If a cell line did not show the hypothesis to be correct, a few scientists have been known to go out of their way to find the "correct" cell line. 

Nevertheless, the iteration of hypothesis, observation, deductive conclusion until you get close to the Objective Truth, is in stark contrast to induction.

An example of painstaking attention to Popper's method is described below:

Quote

To get a better understanding of the hypothetico-deductive method, we can examine the following geographic phenomena. In the brackish tidal marshes of the Pacific Coast of British Columbia and Washington, we find that the plants in these communities spatially arrange themselves in zones that are defined by elevation. Near the shoreline plant communities are dominated primarily by a single species known as Scirpus americanus. At higher elevations on the tidal marsh Scirpus americanus disappears and a species called Carex lyngbyei becomes widespread. The following hypothesis has been postulated to explain this unique phenomenon:

The distribution of Scirpus americanus and Carex lyngbyei is controlled by their tolerances to the frequency of tidal flooding. Scirpus americanus is more tolerant of tidal flooding than Carex lyngbyei and as a result it occupies lower elevations on the tidal marsh. However, Scirpus americanus cannot survive in the zone occupied by Carex lyngbyei because not enough flooding occurs. Likewise, Carex lyngbyei is less tolerant of tidal flooding than Scirpus americanus and as a result it occupies higher elevations on the tidal marsh. Carex lyngbyei cannot survive in the zone occupied by Scirpus americanus because too much flooding occurs.

According to Popper, to test this theory a scientist would now have to prove it false. As discussed above this can be done in two general ways: 1) predictive analysis; or 2) by way of experimental manipulation. Each of these methods has been applied to this problem and the results are described below.

 

Predictive Analysis

If the theory is correct, we should find that in any tidal marsh plant community that contains Scirpus americanus and Carex lyngbyei that the spatial distribution of these two species should be similar in all cases. This is indeed true. However, there could be some other causal factor, besides flooding frequency, that may be responsible for these unique spatial patterns.

 

Experimental Manipulation

If the two species are transplanted into the zones of the other they should not be able to survive. An actual transplant experiment found that Scirpus americanus can actually grow in the zone occupied by Carex lyngbyei, while Carex lyngbyei could also grow at lower Scirpus sites. However, this growth became less vigorous as the elevation became lower and at a certain elevation it could not grow at all. These results falsify the postulated theory. So the theory must be modified based on the results and tested again.

The process of testing theories in science is endless. Part of this problem is related to the complexity of nature. Any one phenomenon in nature is influenced by numerous factors each having its particular cause and effect. For this reason, one positive test result is not conclusive proof that the phenomenon under study is explained. However, some tests are better than others and provide us with stronger confirmation. These tests usually allow for the isolation of the phenomena from the effects of causal factors. Manipulative experiments tend to be better than tests based on prediction in this respect.

 

Source of article for Popper's method in action

Edited June 11, 2022 by jimmydasaint