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  1. 16 Feb '18 10:46 / 8 edits
    A baseless theory that the Sun will not rise on a particular specified completely arbitrary and randomly chosen date in the not-to-far future is falsifiable because you can simply wait until that day and see if the Sun does indeed fail to rise. Surely, such a baseless theory wouldn't be 'scientific' by what the overwhelming majority of reasonable people would naturally mean by and say is a 'scientific theory'!
    So why, according to Popper's philosophy that rejects induction, wouldn't that theory be a 'scientific' theory?

    If you agree with Popper and you try and answer that by saying that we know from our past observations that the Sun does rise each day (so why should that future day be any different?), you are using induction! So that isn't the answer.

    If you agree with Popper and you try and answer that by saying that we will find that theory to be false on that future day and, when we do, that theory will cease to be 'scientific' because it will be proven false, that begs the question why, according to Popper, wouldn't that theory be a 'scientific' theory until that day i.e. in the meantime?

    How do you think Popper may have answered that question?

    Have I subtly misunderstood Popper's philosophy here (it does seem to me ridiculous IF I understood it completely correctly!) and, if so, how so?

    Do you personally think Popper's philosophy is simply wrong?
  2. Standard member DeepThought
    Losing the Thread
    17 Feb '18 04:36
    Originally posted by @humy
    A baseless theory that the Sun will not rise on a particular specified completely arbitrary and randomly chosen date in the not-to-far future is falsifiable because you can simply wait until that day and see if the Sun does indeed fail to rise. Surely, such a baseless theory wouldn't be 'scientific' by what the overwhelming majority of reasonable people would ...[text shortened]... correctly!) and, if so, how so?

    Do you personally think Popper's philosophy is simply wrong?
    If the sole prediction that the theory makes, and can make, is that the sun won't rise on day D then it is not falsifiable in the meantime. On day D it will be falsified, assuming the sun rises as normal, so by then questions regarding it's scientific status become moot. Basically he's saying that to be scientific the theory has to be testable now, at least in principle. I think this is to avoid "wait and see" pseudoscientific claims being able to claim to be science on the basis of his falsifiability system. Something like the electro-weak sector of the Standard Model wasn't testable until they built an accelerator big enough, but could in principle be tested, it was just an engineering problem. Since the required accelerator (LEP) was technically feasible within a sane timescale it counts as science. String theory, on the other hand, seems to fail that test and so appears not to count as a scientific theory in Popper's system.
  3. 17 Feb '18 08:23 / 4 edits
    Originally posted by @deepthought
    If the sole prediction that the theory makes, and can make, is that the sun won't rise on day D then it is not falsifiable in the meantime. On day D it will be falsified, assuming the sun rises as normal, so by then questions regarding it's scientific status become moot. Basically he's saying that to be scientific the theory has to be testable now, at ...[text shortened]... , seems to fail that test and so appears not to count as a scientific theory in Popper's system.
    I think I have just about made up my mind for good; I think Popper's philosophy is simply wrong.
    If the (or one ot the) motivation for his philosophy is to attack pseudoscientific claims, I am sure I can come up with much better methods of attack against pseudoscience ( + religion) that are much more logic-based and soundly-based. I will make this one of the goals of my current research that I will report in my book I am currently writing (to get published, of course). I plan to list (in my book) each pseudoscience I know of and then explain how my system of logic can be used to attack it. But first I need to fully construct my system of logic (it is currently only partially constructed and needs a lot more work).
  4. Standard member DeepThought
    Losing the Thread
    20 Feb '18 07:34 / 1 edit
    Originally posted by @humy
    I think I have just about made up my mind for good; I think Popper's philosophy is simply wrong.
    If the (or one ot the) motivation for his philosophy is to attack pseudoscientific claims, I am sure I can come up with much better methods of attack against pseudoscience ( + religion) that are much more logic-based and soundly-based. I will make this one of the ...[text shortened]... truct my system of logic (it is currently only partially constructed and needs a lot more work).
    That wasn't the motivation. During the early part of the twentieth century a philosophical position known as logical positivism was popular. Bohr was a fan of logical positivism and the Copenhagen interpretation of quantum mechanics was strongly influenced by it, which is a problem because logical positivism is fundamentally broken.

    Logical positivism is based on a sentence of the form: "The only meaningful sentences are those which are empirically verifiable.". There are several problems with this. The first is that it is not clear what they mean by meaningful. "Christ died on the cross for the redemption of our sins." is a meaningful sentence by any normal standard, but pretty unverifiable - since there is scant evidence outside the Bible for the event - and since the Bible specifies an empty tomb, even the only documentary evidence implies archeological verification is impossible. So we can find examples of sentences which are meaningful, but unverifiable. So Logical Positivism's founding sentence is either not true, or simply provides a new definition of the word "meaningful".

    To be a valid philosophy logical positivism's founding sentence should be empirically verifiable. To do this one could generate all possible statements in English (or any other language) and examine each one to see if it is meaningful without being verifiable. or verifiable without being meaningful. For this we need some standard for what being empirically verifiable entails and what being meaningful entails. If no such sentence is found then the philosophy stands. However, one of the sentences we generate is that "The only sentences which are meaningful are ones which are empirically verifiable.", and we have a recursion problem. So the founding sentence of logical positivism fails its own test.

    Popper's aim was to attempt to repair Logical Positivism. He made two changes to the sentence, one was to replace verifiable with falsifiable, the other to reduce the scope to science. He called his philosophy "Critical Realism". The reason for replacing verifiable with falsifiable is sentences such as "All swans are white.", which was believed until they discovered Australia and a black swan. This falsified the sentence. The problem with verificational programmes is that verifying anything requires an exhaustive search and so some sentences cannot ever be verified. Falsification simply requires one instance of the sentence being untrue. The reduction of scope to science was so that the sentence, which is philosophical in nature, is not itself required to be falsifiable.

    That was Popper's basic motivation. However, he then had to put restrictions on what he meant by science and what he meant by falsifiable. The example you cited was part of his discussion of what "falsiable" means. It seems to be a reasonable side condition that the sentence should be testable now. A theory which makes a prediction in a wait and see manner is not falsifiable. I think Popper did well to spot this potential problem. I don't think refuting pseudoscience was a large part of his motivation. I brought that up more as an example of the type of claim that Popper wanted to exclude.

    I think you're making a mistake rejecting Popper outright. I don't think he's wrong in any straightforward way. There are critiques, if you look at the article on Popper on the plato.stansford.edu site you'll probably find some references there.
  5. 20 Feb '18 15:24 / 1 edit
    Originally posted by @deepthought
    The reduction of scope to science was so that the sentence, which is philosophical in nature, is not itself required to be falsifiable.
    Is that a misedit?
    Shouldn't that end with "...required to be verifiable." ?

    Anyway, thanks for clarifying all that. Much appreciated.
  6. Standard member DeepThought
    Losing the Thread
    20 Feb '18 20:10 / 3 edits
    Originally posted by @humy
    Is that a misedit?
    Shouldn't that end with "...required to be [b]verifiable.
    " ?

    Anyway, thanks for clarifying all that. Much appreciated.[/b]
    The sentence is: "The only scientific sentences are those which are falsifiable.". To be internally consistent it has either to be falsifiable or accept that it is unscientific. Since it does not claim to be scientific, but rather philosophical, it is not inconsistent.

    Had the sentence been something along the lines of: "In order to be valid a sentence must be falsifiable." there would be a problem since the sentence is not in itself falsifiable and therefore invalid by its own criterion.

    By reducing the scope of his opus to science Popper could keep it internally consistent.
  7. Standard member sonhouse
    Fast and Curious
    21 Feb '18 03:52
    Originally posted by @deepthought
    The sentence is: "The only scientific sentences are those which are falsifiable.". To be internally consistent it has either to be falsifiable or accept that it is unscientific. Since it does not claim to be scientific, but rather philosophical, it is not inconsistent.

    Had the sentence been something along the lines of: "In order to be valid a sent ...[text shortened]... ion.

    By reducing the scope of his opus to science Popper could keep it internally consistent.
    Has anyone come up with anything that refutes Popper's logic? It certainly has guided science for a long time, eh. But what if there are internal conflicts or some such? Any such problems found?
  8. Standard member DeepThought
    Losing the Thread
    21 Feb '18 06:45
    Originally posted by @sonhouse
    Has anyone come up with anything that refutes Popper's logic? It certainly has guided science for a long time, eh. But what if there are internal conflicts or some such? Any such problems found?
    I don't think there's a problem with Popper's logic or the internal consistency of his ideas, they are well worked out in that sense. I think most criticisms are connected with the way it doesn't really connect with how people do science. One doesn't collect evidence, form a theory and then try to refute it. The actual practice has a paradigm theory (Newton's laws, general relativity, quantum theory and so on) which form the basis for our overall understanding and then something like a supernova is understood on the basis of these paradigm theories. Observation or experiment is then tends to be used to verify rather than refute the theory. When observation or experiment contradicts the lesser theory it tends to be fudged rather than ditched entirely.

    As an example of the way practice tends to be verificational let's consider the discovery of the Higgs Boson. Their detectors picked up pairs of photons at 125GeV (or whatever the energy was) and the signal was strong enough to say that they'd discovered the Higgs Boson. One could argue that the null hypothesis (no Higgs) had been falsified, but really that is another way of saying that the presence of the Higgs has been verified.

    The discovery of quantum mechanics and relativity came about because of the discovery of electron diffraction, in the case of quantum mechanics, and because of attempts to verify Newton's picture by measuring the predicted difference in the speed of light in the direction of the earth's motion - to their surprise the difference didn't exist and they invented an ether theory to get round it - later Einstein presented relativity theory and it became recognized that the Newtonian picture of an absolute frame of reference was incorrect. So the experiment had refuted it - but only really accidentally - neither set of experiments were intended to falsify anything.

    So Popper is correct in the sense that one can be sure that a theory is wrong, but only confident that it is right; the problem is that it doesn't really help one with how to do science. All the discoveries which refuted previous theories happened because people were either trying to verify a different theory or were investigating some phenomenon. If quantum theory is ever falsified it will be because someone is trying to understand some effect and stumbles across a phenomenon it can't explain - it won't be because they are actively trying to falsify it.
  9. 21 Feb '18 07:50 / 8 edits
    Originally posted by @sonhouse
    Has anyone come up with anything that refutes Popper's logic? It certainly has guided science for a long time, eh. But what if there are internal conflicts or some such? Any such problems found?
    If I have understood his philosophy correctly, One implication (which he might himself have been unaware of! ) of his philosophy if valid is it would be impossible to ever totally rationally and scientifically come to the conclusion that any theory is 'probable' but rather merely one theory is 'more probable than another' giving probability a weirdly highly subjective relative value rather than any absolute value. What? So we cannot scientifically say photosynthesis 'probably' results in CO2 intake and O2 released? I have a problem with that.
    I intend to explain in my book a method for totally rationally actually assigning an absolute (as opposed to relative) probability to a scientific theory being correct given the evidence and within the given specified degree or amount of 'correctness' (I will have to first mathematically define the equation for the 'degree of correctness' which, you won't believe it or not, I have already done for the most simple cases albeit that equation doesn't work for most cases; I still need to do a lot more work on it before I get an equation that works for all cases).
  10. Standard member DeepThought
    Losing the Thread
    22 Feb '18 01:49
    Originally posted by @humy
    If I have understood his philosophy correctly, One implication (which he might himself have been unaware of! ) of his philosophy if valid is it would be impossible to ever totally rationally and scientifically come to the conclusion that any theory is 'probable' but rather merely one theory is 'more probable than another' giving probability a weirdly highly su ...[text shortened]... es; I still need to do a lot more work on it before I get an equation that works for all cases).
    I think you might have typed this in a little quickly. The sentence:

    So we cannot scientifically say photosynthesis 'probably' results in CO2 intake and O2 released?

    Should probably read:

    So we cannot scientifically say the theory of photosynthesis, which predicts CO2 intake and O2 released, is probably true?

    I don't know enough about Popper to really say what he had in mind. Most of the above is based on conversations with a former flat mate who had studied philosophy. We are getting into the realms of what I think rather than what Popper thinks, so bear in mind there's some merging going on in the following.

    What I'm about to say works reasonably well for Physics but less so for Biology - and is my idea of what a scientific theory should look like although I don't think it's far off any kind of standard picture, the reason I'm saying this is that I don't want you to think that Popper nor any other person is responsible for problems with it. A theory has a number of elements, there is a formal language for making deductions - maths, logic, or some such, which one can use to answer questions about the world. The theory specifies some objects and their properties, ideally in an axiomatic system, but it tends to be looser than that in practice. There is also a metalanguage - a natural language such as English with some additional jargon - which explains what the formal language means and how to translate questions about the world into the formal language. The metalanguage is responsible for giving meaning to the theory, which otherwise would be indistinguishable from pure maths.

    So as a toy model consider the following question about the world: "We know that Socrates is a man, is he mortal?"

    The formal language has the single axiom:

    ∀x Mx -> Dx

    The metalanguage tells us that the formal language is Classical Logic and that objects with the property M are men and objects with the property D are mortal. A named object such as Socrates has the property M if he is a man and D if he is mortal.

    So we know to translate "Socrates is a man" into the formal language by writing Ma and by using Classical logic we crank the handle and get Da out, which we translate back into the metalanguage and get our answer that Socrates is indeed mortal.

    The basic idea is that the formal language is something one could give to a Turing machine and the only work the user has to do is work out how to ask the right question and translate it into the formal language. So, in this picture, a scientific theory is a string of symbols and some deductive rules, one asks it questions about the world which the theory answers and one can then test the answers against measurements of the world.

    Now we run into a problem: Is the theory true? Whether it is or not depends on what one means by true. What it is is a collection of sentences which describe the world, so it's true in the way descriptive sentences are. It describes the world and some sentences describe the world better than others. So I suspect that what Popper is saying is not that one theory is "more probable" than another, he is saying that one theory is "a better description" than another. Quantum Theory can account for effects which we see that Newtonian Mechanics cannot so Quantum Theory is a better description. However, for most practical purposes, Newtonian Mechanics is perfectly adequate so it's not bad, Quantum Theory just catches more detail.

    In terms of probability, when a theory is falsified it is proven false so has zero chance of being true. It's somewhat difficult to assign a probability to a theory that has not been falsified. Suppose there were two candidate theories for some phenomenon. Some experiments had been done and one of them is confounded by numerical stability problems in the deductive apparatus (call this theory A) - so we have tighter confidence intervals for the other (call this theory B). Although theory B is more probable (we are more confident it is producing results which accord with experiment) we have no real basis for rejecting theory A - when a better algorithm for producing results is found it may be that it provides answers as close to experiment as the theory which does not have numerical problems. So we can give some sort of relative risk given our state of knowledge of the two theories.

    However, assigning some sort of absolute probability is problematic. Since we might discover an effect which falsifies both theories tomorrow it is not really possible to say that theory B is true with a probability of p_B and theory A with probability p_A > p_B, since we have no good way of assigning a probability that there is an unknown effect that will falsify one or other of them. But the confidence intervals do give one a relative risk based on what we do know.
  11. Standard member sonhouse
    Fast and Curious
    22 Feb '18 19:42
    Originally posted by @deepthought
    I think you might have typed this in a little quickly. The sentence:

    So we cannot scientifically say photosynthesis 'probably' results in CO2 intake and O2 released?

    Should probably read:

    So we cannot scientifically say the theory of photosynthesis, which predicts CO2 intake and O2 released, is probably true?

    I don't know enou ...[text shortened]... her of them. But the confidence intervals do give one a relative risk based on what we do know.
    Do you think he was thinking in terms of supernatural phenomena, where you cannot falsify such ideas, I hate to elevate that to 'theory'
  12. Standard member DeepThought
    Losing the Thread
    22 Feb '18 22:17
    Originally posted by @sonhouse
    Do you think he was thinking in terms of supernatural phenomena, where you cannot falsify such ideas, I hate to elevate that to 'theory'
    Based on a skim read of Wikipedia, if he had pseudo-scientific claims in mind when he added the side condition humy was asking about it's more likely to be Marxism, which Marx et al frequently described as "Scientific Socialism". He developed his ideas in the 1930s when both the fascists and the communists would use claims about science to try to justify their respective ideologies or particular policies. Religious statements would come under that umbrella, which isn't a problem for most believers, just the ones who want to use scientific language to justify their beliefs.

    Having said that I think it's more likely that he was simply being thorough and ensuring that there were adequate constraints on falsifiability. Since for him any theory that hasn't been proven false is provisionally true he needs some way of constraining what an adequate theory actually is. A theory that hasn't been falsified is not so much true as not false.

    The actual sentence humy started with, or at least a version of it, was: "The sun will not rise on New Years day.". Popper's ruling this out because one can't falsify it, or for that matter verify it, until the day. However a sentence such as: "The sun will not rise on New Years day, and there will be portents of this in the heavens in the meantime." would not be ruled unscientific by this side condition because we can look for the portents.
  13. Standard member sonhouse
    Fast and Curious
    22 Feb '18 23:16
    Originally posted by @deepthought
    Based on a skim read of Wikipedia, if he had pseudo-scientific claims in mind when he added the side condition humy was asking about it's more likely to be Marxism, which Marx et al frequently described as "Scientific Socialism". He developed his ideas in the 1930s when both the fascists and the communists would use claims about science to try t ...[text shortened]... e." would not be ruled unscientific by this side condition because we can look for the portents.
    So part of his agenda was political. Interesting. He was a product of his times.