Is Popper’s Falsifiability Test Reasonable?

· philosophy of science

Popper states in Knowledge Without Authority (1960):

  • The empirist’s questions “How do I know? What is the source of your assertion?” are wrongly put. They are questions which beg for an authoritarian answer.
  • I propose to replace, therefore, the question of the sources of our knowledge by the entirely different question: “How can we hope to detect and eliminate error?

This is Popper’s falsifiability test: A theory is considered scientific as long as it is not falsified in the sense that there is a consequence or prediction of the theory, which does not match with observation of reality.

Popper’s test thus does not ask for justification or positive evidence that the theory is correct, only for negative evidence as lack of falsification.

Popper’s test represents a break with classical rational science based on positive evidence and reason, and one may ask what made Popper take the bold step from positive evidence to lack of negative evidence?  Does it reflect the break from classical rational deterministic physics into the modern physics of statistical mechanics and quantum mechanics which took place at the turn to the 20th century?

Yes, there seems to be substantial positive evidence supporting this idea: The fundamental reason seems to be that the basic assumptions of modern physics being based on statistics, cannot be directly tested and justified and thus a weaker test is needed to be able to claim that modern physics is science, which Popper then offers in the form of his falsifiability test.

The basic assumption of molecular chaos of statistical mechanics can thus according to Popper be adopted without positive evidence, and can be viewed to be valid as long as no consequence of the assumption contradicts observation.

But to draw consequences from molecular chaos is difficult since it requires solution a Boltzmann’s equation, which is impossible except in a few simple cases. This makes statistical mechanics into a scientific theory according to a very weak test.

But viewing a theory with weak support as a scientific theory with solid support, is potentially dangerous since the theory may give grossly incorrect predictions.

Comparing with a legal case, we know that to convict someone for murder it is necessary with some positive evidence which connects the suspect to the deed, like fingerprints. We know that lack of negative evidence, such as lack of alibi, is not enough for conviction to the electric chair. It should neither be enough to convict a theory to the heavy burden of being scientific.

Popper’s negativism expresses his criticism of positivism, which serves the purpose of making modern physics based on statistics acceptable as science.

13 Comments

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  1. SuperNova

    I have one question for you.

    Your hypothesis that the world is an analog computation, how do you prove this?

  2. SuperNova

    To clarify, in analogue with the murder trial, where’s the positive evidence?

  3. claesjohnson

    That the world is analog computation is not a basic assumption. It is just way of summarizing evidence that it is possible to simulate physical processes by computation. Basic assumptions are Newton’s laws and constitutive relations such as Hooke’s law.

  4. SuperNova

    So you assume,

    1. If the world is a finite precision computation then we can simulate physical processes with computations.
    2. We can simulate physical processes with computations.
    =>
    3. Hence the world is a finite precision computation.

    This is completely faulty logic and can not be used as evidence for that assumption.

    Or do you now claim that some basic principles are in no need of positive verification?

  5. claesjohnson

    No this is not the logic I use: I assume Newton’s laws of motion and show that the corresponding equations are solvable by computation and find that this allows computational simulation of real phenomena. I thus find evidence that the world can be simulated by digital computation. I then say that this gives evidence that the world can be seen as a form of analog computation. I do not assume that the world is a clock with finite precision or a computation of finite precision. Instead I give evidence that the world can be seen as such. If you don’t accept this conclusion, nothing de facto changes: The essence of computational solution of the equations expressing Newton’s laws remains the same.

  6. SuperNova

    Ok, so you say “can be seen as”. I assume you mean, can be modeled as, then.

    So in what way does this stand out from ordinary modern physics?

  7. claesjohnson

    I do not use statistics while modern physics is loaded with statistics. I suggest to modify rational mechanics by finite precision computation and maintain rationality, instead of of throwing out rationality by resorting to statistics.

  8. SuperNova

    But, by examining the success of introducing statistics as an integral part of physics the only rational thing would be to let statistics pertain.

    • claesjohnson

      The success is a myth. The reality is that it is a catastrophe.

      • SuperNova

        Easy thing to claim.

        How do you empirically back up that claim?

  9. claesjohnson

    If you study the subject you will find that the predictions of statistical mechanics are very vague and difficult to use for practical purposes. The statistical interpretation of the wave function has been criticized by many sharp scientists including Einstein and Schrödinger. Physics is not doing statistics, only human statisticians.

    • SuperNova

      o my…

      I saw your contribution at the Fredomfest. It looked like straw men and loose innuendo heaven sprinkled with non sequitur.

      Do you realize how ignorant you look.

      My hypothesis from this is that you actually don’t know much physics. My guess is that you want modern physics to be wrong, so bad, that you started to try to dismantle it before you really understood it.

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