FALSIFIABILITY FOR DUMMIES
As science penetrates cosmological and sub-atomic realms, hypotheses attempting to account for features that are often paradoxical become increasingly esoteric and theoretical. Traditionally, reproducible experiments determine the validity of theoretical propositions, but the magnitude, technical inaccessability and costs makes this approach impractical. Consequently a huge body of untested and competing theoretical hypotheses have accumulated that leave virtually all systems composing the anatomy of reality in question.
Testability: A central methodology in the philosophy of science is empirical experiments, or dependence on evidence. In short, a hypothesis is testable if there is some real hope of deciding whether it is true or false of real experience.
Karl Popper proposed a epistemological methodology for evaluating hypotheses including those that could not be experimentally tested and insisted that the term "scientific" can only be applied to statements that are falsifiable. He asserted that no empirical hypothesis, proposition, or theory can be considered scientific if it does not admit the possibility of a contrary case.
[1]Falsifiable does not mean false. For a proposition to be falsifiable, it must be possible, at least in principle, to make an observation that would show the proposition to fall short of being a tautology, even if that observation is not actually made. For example, the proposition 'all swans are white' would be falsified by observing a black swan, which would in turn depend on there being a black swan somewhere in existence.[/1]
That such theories are unfalsifiable says nothing about either their validity or truth. Concepts that are not falsifiable may still have value. But it does assist us in determining to what extent such statements might be evaluated. If evidence cannot be presented to support a case, and yet the case cannot be shown to be indeed false, not much credence can be given to such a statement.
Finally, falsifiability is a necessary property of empirical statements- it is not a sufficient property. This means that it takes many other properties for a proposition to qualify as being empirically meaningful.
[2]Tom Mattson offers criteria for distinguishing science from pseudoscience?"
Here is what makes a theory "scientific".
1. It must be consistent.
That is, for no statement X should it be possible to deduce both X and NOT X from the axioms of the theory.
2. It must be valid.
That is, its claims must be correctly derived via logic and, if applicable, mathematics.
3a. It must be satisfiable.
That is, it must make claims that are subject to empirical investigation. If a theory is analytically false, then it is known to be trivially false with no need for investigation.
3b. It must be falsifiable.
That is, it must make claims that, if false, will show the theory to be false. If a theory is analytically true, then it is known to be trivially true with no need for investigation.
Points 3a and 3b can be summed up as:
3. It must be contingent.
That is, it must be contingent on the outcome of experimental investigations.
Let\'s take a look at the development of a toy pseudoscientific theory.
Hypothesis 1a: I have a rock that keeps tigers away from my home.
(Yes, that comes straight from The Simpsons. Is there anything that show isn't good for?
This theory is both consistent and valid, but only trivially so because it has only one prediction!
This theory is also both satisfiable and falsifiable:
*Satisfiable because the theory is satisfied when no tigers are around.
*Falsifiable because the theory is shown to be bunk if a tiger is around.
This theory is thus scientific.
So, how do I investigate it? Well, I could observe the area around my home, and if no tigers show up then I take that as strong inductive evidence that the theory is good.
But is that enough? I could also deliberatly bring a tiger around and see if something (presumably attributable to the rock) doesn't keep the tiger from coming around. If that works, then I try to develop other explanations (besides the rock) that caused it. If it does work, then I know the theory is no good, and it is thus said to have been falsified.
Now, let's say I really like my theory, so I weaken its claim so that I can hang onto it.
Hypothesis 1b: I have a rock that keeps tigers away from my home, except when there is a tiger around.
What happens when there is no tiger? The theory is satisfied.
What happens when there is a tiger? The theory is satisfied.
Those are the only options! Since it is impossible for the theory not to be satisfied, it is unfalsifiable and therefore pseudoscience.[/2] |
[3]In his recent book, Stephen Hawking, The Universe in a Nutshell, summarised Popper’s approach thus:
"According to Popper’s way of thinking, a scientific theory is a mathematical model that describes and codifies the observations we make. A good theory will describe a large range of phenomena on the basis of a few simple postulates and will make definite predictions that can be tested. If the predictions agree with the observations, the theory survives that test, though it can never be proved to be correct. On the other hand, if the observations disagree with the predictions, one has to discard or modify the theory."
Hawking, with his disarming, dry humour, adds in parentheses- ("At least that is what is supposed to happen. In practice, people often question the accuracy of the observations and the reliability and moral character of those making the observations.")[/3]
Indeed, there are many problems with Popper's account of progress through falsificationism, not least the belief that some kinds of scientific evidence, including probabilistic evidence, are unfalsifiable and the belief that, in the lab, scientists often ignore falsification.
[4]Some propose that most, perhaps all, of the key claims of the theory of evolution are not falsifiable since there are no tests that can be devised that could possibly disprove "evolution as change" claims, for example, and thus those claims are not science. They charge that this is the reason the lengthy and educational sections on falsifiability were removed from the Kansas standards.[/4]
But Popper says that for a proposition to be falsifiable, it must only in principle be possible, to make an observation that would show the proposition to fall short of being a tautology, even if that observation is not actually made- that it need only admit the possibility of a contrary case- which is what claims in evolutionary theory do.
[5]Falsifications can be as fuzzy and elusive as confirmations. Einstein's first cosmological model was a universe as static and unchanging as Aristotle's. Unfortunately, the gravity of suns would make such a universe unstable. It would collapse. To prevent this, Einstein, out of thin air, proposed the bold conjecture that the universe, on its pre-atomic level, harbored a mysterious, undetected repulsive force he called the "cosmological constant." When it was discovered that the universe is expanding, Einstein considered his conjecture falsified. Indeed, he called it "the greatest blunder of my life." Today, his conjecture is back in favor as a way of explaining why the universe seems to be expanding faster than it should. Astronomers are not trying to falsify it; they are looking for confirmations.[/5]
[6]What makes a "Popperian" theory un-falsifiable can usually be applied also to non-formal theories.
A tautological claim is un-falsifiable:
("black is black").
A claim that contains an internal contradiction is un-falsifiable:
("reality is unreal").
A claim that predicts everything is un-falsifiable:
("it's God's will"). Etc.
And the most important one is the "falsifiability" characteristic itself:
- claims that don't make predictions are un-falsifiable.[/6]
[7]Is Seti- falsifiable?
Observation: "Life exists on Earth."
Positive Hypothesis: "Life exists on planets other than Earth."
Negative (Null) Hypothesis: "Life does not exist on planets other than
Earth."
If no signal is ever found then neither hypothesis will have been falsified and both possibilties will remain true. If a signal IS found the negative hypothesis will have been falsified and the positive hypothesis affirmed. But we presume that the signal (and the means by which it was gathered) can still be falsified and that's why the positive hypothesis is perfectly valid. Either way, it's good science. Just a matter of which way you want to view it. There is no
particular logical requirement for choosing the null argument.[/7]
[8]Falsificationism Falsified:
It is argued that falsificationism relies on an incorrect view of the nature of scientific inquiry and that it is, therefore, not a tenable research methodology.[/8]
[9]Indeed, there are many problems with [Poppers] account of progress through falsificationism, not least the belief that some kinds of scientific evidence, including probabilistic evidence, are unfalsifiable and the belief that, in the lab, scientists often ignore falsification.[/9]
Critical Rationalism was championed by Karl Popper around the 1930’s and his principle of Falsifiability was a criticism of Logical Positivism. CR claimed that science was privileged when seeking "truth" because the scientific method subscribed to the principal of ‘falsifiability’- that is the 'lone path to truth"- in the method of making predictions that allows science to be revised when those predictions fail to materialize. Unfortunately, CR has been dismissed by virtually all philosophers of science since then. Paul Feyerabend is well known for maintaining that you cannot differentiate between myths and science and observed that there is no objective reality we can confirm outside our perceptions of it: falsifiability goes down the drain if all of our testing is a victim of our own subjectivity.
Thomas Kuhn observed that the revision of scientific theory has more to do with the culture and posturing of scientists of the moment than it does with anything else. Khun was a 20th century philosopher, physicist and historian of science whose work challenged the doctrine of cumulative scientific progress and argued that science moves through dramatic revolutions, or paradigm shifts, rather than steady, rational, empirically-guided falsification. The notion of the paradigm is central to Kuhn's work. Although his definition of the word is quite broad, it can generally be understood as the backdrop of assumptions and beliefs that lie behind scientific research. He also argued that scientists' own values influence theory choice and that scientists' claims to rationality and strict empiricism are not upheld in genuine scientific practice. Kuhn's historical work certainly showed that the traditional understanding of a scientist as an ideally rational agent, whose observations and experiments are untainted by subjective value concerns, is simply inaccurate.
Critical Rationalism was championed by Karl Popper around the 1930’s and his principle of Falsifiability was a criticism of Logical Positivism. CR claimed that science was privileged when seeking "truth" because the scientific method subscribed to the principal of ‘falsifiability’- that is the 'lone path to truth"- in the method of making predictions that allows science to be revised when those predictions fail to materialize. Unfortunately, CR has been dismissed by virtually all Philosophers of Science since then. Feyerabend is well known for maintaining that you cannot differentiate between myths and science and observed that there is no objective reality we can confirm outside our perceptions of it: falsifiability goes down the drain if all of our testing is a victim of our own subjectivity.
References:
[1] wiki-falsifiability
[2] -see Tom Mattson post- physicsforums
[3]- The Science of Science- Nicholas Astete
[4] Kansas Board on ID
[5] A Skeptical Look at Karl Popper- Skeptical Inquirer (2001). by Martin Gardner
[6] listhost.uchicago
[7] gatago.com
[8]
Sven Ove Hansson- Department of Philosophy and the History of Technology, Royal Institute of Technology, Teknikringen 78, Stockholm, Sweden
[9] sirc.org- why science matters
Falsifiability Another managible definition
Falsifiability- Not for Dummies
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