What does it mean that a theory, to be valid, must be, among other things, also “falsifiable”?


This confuses a lot of people, because when you first think about it, saying that a theory has to be falsifiable implies it is only a good theory if falsified.

But all that it means is that the theory needs to specify what would make it false.

The problem with all theories is that very often we are making a prediction by it. And just because the prediction is true in some cases, does not make it true in other cases.

So even though we could define a theory like this

  • all the balls in this box are red

What we really should be doing is this

  • none of the balls in this box are not red

Note that both statements are equivalent in truth – meaning that they are saying the same thing logically.

But by stating it the second way, it is clear what the “test of truth” has to be. We have to test every single instance of “ball” for the quality “red”.

So now let’s go back to my explanation.

All that it means is that the theory needs to specify what would make it false.

So now let’s look at the difference between a hypothesis and a theory.

  • A hypothesis is a STATEMENT that can be either true or false.
  • I hypothesize that this is a box of red balls. Note that this statement is a bit unclear about what would make it true or false.
  • A theory is a HYPOTHESIS that is falsifiable.
  • All the balls in this box are red – or none of the balls in this box are not red. Note that we do not have to make the statement a statement of falsifiability. All that is needed is that we can extract such a statement from it.

So now to recap, because the difference is significant.

  • A theory must be able to be expressed as a statement, or as a set of statements. That is clearly either true or false, but can’t be both.
  • In other words “the universe could be an onion” is not really that sort of statement. “The universe is an onion” is that sort of statement.
  • A hypothesis is also expressed this way, but with insufficient detail to be able to say whether it is true or false, even with more evidence.
  • A theory has to have enough detail to be able to say if it is true or false, with more evidence.

And we can see these distinctions when we consider something like “string theory”.

Note that many physicists, even if they support string theory, will agree that it is a hypothesis – so far as generally agreed what the evidence of it will be.

For example, one aspect of String Theory is that much of the “evidence” for it is also “evidence” of Standard Model.

And that is why I also now define for you a third concept – that of MODEL.

A model is the combination of theories, hypotheses, and evidence that compose an “explanation” of the evidence.

For example, the various models of man-made climate change. These often confuse the man-made climate change DENIER, because the evidence, the hypotheses, and the theories are constantly being all revised.

Suffice it to say that there are two problems with “String Theory”.

  • It is not really a theory. It is only referred to as such because once we have specific evidence of it – as the alternative explanation – that Standard Model can’t explain, we can start specifying the theory well enough to make it falsifiable.
  • And the reason we have a problem in specifying it that way is because the “dimensions” of the “strings” are too small to observe. It is an ELEGANT “theory” of sorts, but there is nothing we can say about it that is TESTABLE – just yet.
  • It is competing not just with another theory. It is competing with a MODEL, that has evidence for it, and that is being constantly revised and updated, as the component theories are being “falsified”.
  • The hypothesis is so far restricted to using the same evidence as the model. And the only “evidence” that it is the “better explanation” is that it is more elegant, which really just means that it is simpler to describe.

Having said that, since there is no “law” that says that a new MODEL can’t use the same evidence as an older MODEL, hopefully one day there will be more than just the hypotheses and evidence that is shared with the Standard Model, and we can start referring to the String Model.

But when we construct a theory, we need to describe it with enough detail to make it clear what we would need to do to falsify it.

And we can see this in Darwin’s Orgin of the Species book. The basic theory is easily described with two bullet points. Two statements.

  • All life is biologically evolved by a process of selection and natural variation (random mutation).
  • All species therefore evolved from earlier species, other than the very first species (plural).

And the theories (or should I now say MODELS) are still being revised all the time.

  • We can already see a slight revision to the first bullet point. We now have to include “genetic engineering” – where the DNA is “hacked” and not randomly mutated and then selected.
  • We already see evidence of the first bullet point, and Darwin knew this when he observed natural selection. The artificial selection of domesticated plants and animals.
  • We already see an overwhelming evidence of the second bullet point. As we can see by anyone who argues with me about that fact, when they demonstrate their ignorance of science.
  • And there is still some question as to the details. Is the first DNA “alive”? What was the first thing that we can say is “alive”? And was that the only “common ancestor”?

But in each one of these components of the model, we can say which one is a theory, which one is a “proved” theory (by being proved by compliance in all instances – for example, DNA is that sort of proof), and which one is still a hypothesis, even if reasonable.

Let me give you just two more examples of this.

  • I often say that DNA is the method of evolution, DNA is the record of evolution, and because of this DNA is the proof of evolution. We can PROVE the basic theory of Darwin just by demonstrating that what DNA does is evolution, and this would mean that every living thing evolves if it has DNA.
  • Which is why we define something as “alive” if it has DNA and can have descendants. Some evolutionary biologists may say that RNA only viruses are alive, but please remember Darwin did not know about viruses and did not define “life”.
  • But the informed speculation about the first life forms, referred to by the people that do not believe that such a thing is possible as “abiogenesis”, are better referred to as hypotheses.
  • Even though they can be quite specific in the details.
  • There is no way of “proving” it, because their DNA would have been so very simple there would be no detectable trace of it in our inherited DNA. We would not know what it is when we saw it, if we saw it.
  • There is no way of “proving” it because one strand of DNA and a few protein molecules do not fossilize at all. We would not know it was even there, if it time transported to the future and sat on a microscope slide.

But I could be wrong. Tell me how to falsify the hypothesis, even if only by time travel, and it becomes a theory.


The meaning of falsifiable is crucialto what is finally called a “theory”; in that once an idea (properly called a hypothesis) is presented, it must be presented so that it is possible to ‘prove that it wrong if it is wrong’. That presentation of some types of idea is very difficult to do! For others it is impossible!

Other Science types, often those whose older ‘theory’ would now be displaced/replaced if it passes the process, try to prove that the new hypothesis is wrong. If they can’tdo so, the hypothesis is moved up to what is now recognized as a new theory!

Being called a theory does notmean that it is ‘certainly correct’ but only that those with an interest in disproving it have not been able to do so! That is actually a very highstandard; if the process is properly done! Cheating sometimes happens!

Anyone who still believes that a theory is true, in any reasonable way, simply don’t understand what a ‘theory’ is; nor do they understand the demanding process that it had to go through and survive.

In my Books I present a few which suggest that it is better to say that Science tells such good stories that they can be relied upon to predict outcomes much better than an exhaustive series of tests ever could do.

Many with a poor education, or poor teachers/professors, disagree; because they don’t really know how Science ‘works’ at explaining ‘things and processes’ in the Energy/matter paradigm.

Many perfectly good and useful ideas in Philosophy cannot ever be written as acceptable hypotheses; so such ideas can never become ‘theories’!
They are still good and useful ideas though!


In order to ascertain whether a theory or hypothesis is valid or not, you must be able to test it. It is not enough to just test it to work, because you can easily set up a hypothesis which would always yield positive results no matter what test you throw it.

You must also be able to think up a scenario where, if a certain result comes up, your hypothesis or theory must be false. If there is no such scenario, then the hypothesis/theory is impossible to test.

Take, for instance, the interesting difference between the number of chromosomes of humans and the other primates. We know that chromosomes can fuse and split. So we can predict that either a chromosome pair split for each of the other primates, or that a chromosome pair fused once for humans. It is more likely that chromosomes fused once than split thrice.

Chromosomes also have these parts called centromeres where one chromosome of the pair link up to the other chromosome of the pair, and telomeres which protect the end of DNA.

That gives us something to test: in human chromosomes, there has to be an extra centromere (possibly inactive) in one chromosome, and a bunch of telomeres in the middle where the two predecessor chromosomes fused. If we can’t find that, then there’s something fishy about common ancestry with the other primates. And that also means that the theory of common descent is testable and thus falsifiable.

(And we find that in human chromosome 2, there are telomeres in the middle indicating a fuse at base pairs 114,455,823 to 114,455,838. There is an inactive centromere at base pairs 133,174,147 to 133,402,426 that corresponds to the centromere in chimpanzee chromosome 2B.)

A non-falsifiable theory would be “that is the way the Maker made it”, which was the how the defense responded in the Kitz miller v Dover Area School District trial.


Falsifiable = Testable.

A passport theorizes about who you are. When an immigration officer compares your face with the photo, they can assert whether that theory is true or false.

That small booklet that says “passport” theorizes that it’s a passport. When an immigration officer scans the book with their authenticator, they can assert whether that theory is true or false.

You just woke up and you’re theorizing you may be out of milk. You shake the jug and by the sound and weight can assert whether that theory is true or false.

Even after assertions are made, we can test again to confirm we are correct.

Now imagine if there was no test? You could never discover whether a theory is true or false. An untestable theory is falsifiable.

It’s important to note that here “theory” means “hypothesis”. Every mention of “theory” above can be replaced with “hypothesis”. This is not to be confused with “theory” as in “model” as used in quantum theory and string theory.

The next best thing to performing a test is to think up a test. These are thought experiments and are often enough to test for testability. If a test is not even imaginable, we call that hypothesis falsifiable, and proceed to classify it as inconsequential.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s