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Re: [evol-psych] Re: Scientific justifications

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  • Robert Karl Stonjek
    From: Jeremy Bowman ... -- It may undermine our certainty, but if a hypothesis is true, then it s ABSOLUTELY true. It accurately
    Message 1 of 6 , Jul 31, 2003
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      From: "Jeremy Bowman" <bowman@...>

      Robert Karl Stonjek replies to Don McEachron:

      > It is the ongoing nature of science
      > that undermines absoluteness.

      -- It may undermine our certainty, but if a hypothesis is true, then it's
      ABSOLUTELY true. It accurately describes the way the world is, and that's
      that. Again, OUR confidence is an entirely different thing from ITS truth
      or falsity.

      > Thus no theory is permanent or
      > is absolutely correct.

      -- This is what philosophers usually call "the pessimistic induction".
      Almost all past theories have been abandoned as false, this idea goes, so
      they're all going to be abandoned eventually. But why think that way?
      Science is a relatively recent development. Like riding a bike, our first
      few attempts are bound to fail, but once we've got it, we've got it. Some
      scientific hypotheses we can already be very, very confident about. For
      example, I'd be absolutely amazed if we ever abandoned the hypothesis that
      "millions of years ago, very large reptiles lived on earth".

      All the best -- Jeremy Bowman

      RKS:
      One of the most common limitations placed on accepted theory is the scope
      and precision to which a hypothesis is true. Limiting the scope is the most
      common form of revision of hypothesis. In physics it is said that the "laws
      of physics are not obeyed at the singularity" ie at around the time of the
      big bang and at the centre of black holes. This disqualifies the
      absoluteness of all physics theory.

      On the issue of the dinosaurs, there is no guarantee that they will always
      be classified as reptiles and they are not classified as reptiles in all
      current or recent classifications systems. For instance they are not
      classified as such in the Linnaean system. There is some probability that a
      new classification system may one day evolve which might not classify
      dinosaurs as reptiles. Your above statement would no longer be correct.

      Further, the hypothesis you refer to is not that dinosaurs existed, but how
      fossil bones should be interpreted. The interpretation, that seems secure
      at present, is that most are the remains of animals, generally dinosaurs,
      that existed mainly in the Mesozoic era. Of course Trilobites were not
      dinosaurs and they existed before dinosaurs.

      Kind Regards,
      Robert Karl Stonjek.
    • Robert Karl Stonjek
      Jeremy Bowman But in any case, how certain or uncertain we are about a claim s truth is a different thing altogether from its being true. If it is true, then
      Message 2 of 6 , Aug 2, 2003
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        Jeremy Bowman
        But in any case, how certain or uncertain we are about a claim's truth is a
        different thing altogether from its being true. If it is true, then it is
        "absolutely" true, and it is so because of the way the world is arranged,
        not because of our confidence. Science is aimed at uncovering truths like
        that. I believe that we can be reasonably certain about some scientific
        truths, although that has no bearing on the "absoluteness" of those truths.

        RKS:
        I think most physicists believe they are searching for models which accurately reflect nature.  The mathematics discovered is not an intrinsic quality of nature any more than geometric relationships are.
         
        Euclidean geometry, for instance, accurately models objects on flat surfaces.  The laws he discovered still hold, as do the relationships between angles and so on.  Even so, Euclid's laws were found to be limited in the early 19th century and this led to non-Euclidean geometry.
         
        Modelling is not the same as truth.  One can say that a model is true, if we stretch the word a bit, but most models are accepted as accurate approximations to within the parameters thus far tested by experiment or observation.
         
        No-one can say that "inflation theory" is true, for instance, even though the basic principles of the model are now generally  accepted.  The model is not "true" or "false", it is a model that is useful for understanding the first fractions of a second of the big bang (model) and it explains the "flatness" and "horizon" problem.
         
        Considering the sparseness of historical knowledge that is bound to plague disciplines like Evolution and its various branches, one can not say with any certainty that any models are true.  Rather, they explain certain phenomena, though other phenomena may contradict it, and they seem to predict some results. 
         
        The various models of human evolution fall into this category.  Homo Erectus had a Broca's cap, indicating that they were language ready.  Working with the model of human development that says that humans were language capable at that point will lead some researchers in one direction, those using a model of language development that says that only Homo-sapeins were capable of verbal communication will be led in other directions.
         
        It is quite common for more than one hypothesis to model the same phenomena  where there is a sparsity of observational or experimental data.  Advocates of each model do not generally argue for the truth of their model, but argue instead that their model more accurately reflects the nature of the phenomena so modelled.
         
        On the subject of white snow, it is worth pointing out that snow is white under laboratory conditions.  In practice it can be a range of colours from dirty brown to orange to black to yellow depending on environmental conditions.  One could make a similar claim about water - under laboratory conditions, water is an insulator ie it does not conduct electricity.  That is true - but in practice water is a solvent and it is the dissolved material in water which makes it such a great conductor.
         
        There are also unprovable hypothesis.  For instance, if we made the claim that no two snowflakes are the same, then this can only be true until two identical snowflakes are discovered.
         
        Kind Regards,
        Robert Karl Stonjek.
      • Irwin Silverman
        On Sun, 3 Aug 2003, Robert Karl Stonjek wrote:
        Message 3 of 6 , Aug 3, 2003
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          On Sun, 3 Aug 2003, Robert Karl Stonjek wrote:

          << I think most physicists believe they are searching for models which
          accurately reflect nature. The mathematics discovered is not an
          intrinsic quality of nature any more than geometric relationships are.

          Euclidean geometry, for instance, accurately models objects on flat
          surfaces. The laws he discovered still hold, as do the relationships
          between angles and so on. Even so, Euclid's laws were found to be
          limited in the early 19th century and this led to non-Euclidean
          geometry.

          Modelling is not the same as truth. One can say that a model is true,
          if we stretch the word a bit, but most models are accepted as accurate
          approximations to within the parameters thus far tested by experiment
          or observation >>


          Well put, but, sadly, not well heeded. This is particularly
          true of contemporary 'cognitive neuroscientists', who seem really to
          believe that their beeps and squiggles are actual representations of
          reality while the rest of us, observing actual behavior, are working in a
          world of fancy - for e.g., the spate of recent claims that, whatever the
          behavioral evidence, the modular mind 'could not exist' because the theory
          of brain currently in fashion suggests that it doesn't work that way.
          This is not to deny that current technology may well bring us to
          breakthroughs in the understanding of how the brain works to generate
          cognition and behavior. But this will also require researchers who
          understand how science works to generate conclusions.
        • Jeremy Bowman
          Having spent about 20 years of my life defending scientific realism against confusion of various kinds, I don t want to spend too much more time on it. My main
          Message 4 of 6 , Aug 3, 2003
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            Having spent about 20 years of my life defending scientific realism against
            confusion of various kinds, I don't want to spend too much more time on it.
            My main claim in this discussion has always been:

            TRUTH =/= CERTAINTY

            (Where '=/=' means "is not the same thing as".) Here's another way of
            expressing the same simple idea:

            P IS TRUE =/= P HAS PROBABILITY OF 1

            A sentence is true in much the same way as a man is an uncle. When your
            sister in Antarctica gives birth, that makes you an uncle. You don't have
            to know that she is in Antarctica, or that she has given birth, in fact you
            don't even have to know that you have a sister! But as a matter of brute
            fact, if she really is your sister, and she really has given birth, then
            you really are an uncle.

            When things are arranged in a particular way, any sentence that says they
            are arranged that way is true. You don't have to believe it with any degree
            of confidence, in fact no one has to believe it at all. But as a matter of
            brute fact, if the words in the sentence really refer to those things, and
            those things really are arranged in the way the sentence says they are
            arranged, then the sentence really is true.

            So truth is a simple, "transparent" sort of relation between sentences and
            the real world. By contrast, the degree of confidence a person can have in
            one of his beliefs is not at all simple or "transparent". Whatever we call
            it -- confidence, certainty, justification, probability, whatever -- it is
            not at all like being an uncle. It is a complicated, contextual sort of
            attribute -- more like being "generous" (to pick another human
            characteristic out of the air).

            There are lots of generous people who are not uncles, and lots of uncles
            who are not generous. There are some generous uncles, but there is only a
            loose connection between being generous and being an uncle. Similarly,
            there is only a loose connection between feeling justified in believing
            something, and that belief's actually being true. You can feel very certain
            about one of your beliefs, and yet still be wrong. Conversely, you can feel
            very uncertain about it, and yet it can still be true.

            Robert Karl Stonjek writes:

            > I think most physicists believe
            > they are searching for models
            > which accurately reflect nature.

            -- I'm happy enough with that. Strictly speaking, truth and falsity are
            attributes of declarative sentences of a language. But we can stretch usage
            a bit and speak of other representational media as being more or less
            "accurate". The more accurately a model reflects reality, the "truer" it
            is. This usage meshes quite smoothly with ordinary talk of maps (say) being
            "right" and "wrong" when they more or less accurately capture features of
            the terrain. For example, early maps of North America showed California as
            an island. These maps were wrong -- stretching the word a bit, they were
            "false". They were false because as a matter of brute fact the Baja
            California is attached to the rest of America. Given that blue areas stand
            for water, brown areas stand for land, etc., in respect of this detail
            these maps expressed a falsehood rather than a truth.

            > Modelling is not the same as
            > truth.

            -- No, but being an accurate model is closely analogous to being a "true"
            model, and being an inaccurate model is very closely analogous to being a
            "false" model.

            > One can say that a model is true,
            > if we stretch the word a bit, but
            > most models are accepted as
            > accurate approximations to
            > within the parameters thus far
            > tested by experiment or
            > observation.

            -- This is an example of the sort of confusion of truth and certainty I
            have been complaining about. Any hypothesis (theory, model, etc.) is a
            guess. If it's a lucky guess, then it's true (accurate), and if it's
            unlucky it's false (inaccurate). But the extent to which a hypothesis
            (theory, model, etc.) is ACCEPTED AS true (accurate) is a measure of OUR
            CONFIDENCE in believing it. Its actual truth (accuracy) or falsity
            (inaccuracy) is a different thing altogether.

            > No-one can say that "inflation
            > theory" is true, for instance, even
            > though the basic principles of the
            > model are now generally
            > accepted.

            -- No one can say it with certainty, but surely we can say it without
            certainty?

            > Considering the sparseness of
            > historical knowledge that is
            > bound to plague disciplines like
            > Evolution and its various
            > branches, one can not say with
            > any certainty that any models are
            > true.

            -- Agreed, but who needs to say it with certainty?

            > Rather, they explain certain
            > phenomena, though other
            > phenomena may contradict it, and
            > they seem to predict some results.

            -- They wouldn't explain those phenomena unless we assumed the explanatory
            hypotheses were true. To the extent that models cannot be understood as
            true, they fail to explain. The basic outlines of evolutionary theory are
            not models, and they can be expressed as non-metaphorical sentences of a
            language like English, and they are literally true or false. My guess is
            that most of these sentences are true.

            > It is quite common for more than
            > one hypothesis to model the same
            > phenomena where there is a
            > sparsity of observational or
            > experimental data. Advocates of
            > each model do not generally argue
            > for the truth of their model, but
            > argue instead that their model more
            > accurately reflects the nature of the
            > phenomena so modelled.

            -- Arguing for the greater "accuracy" of one model over another is the same
            thing as arguing that it more closely approximates the truth. The word
            'true' is sometimes avoided (in physics, mostly) because these models
            consist of mathematical formalisms rather than plain English sentences. But
            many of them can be roughly "translated" into such sentences, and those
            sentences are literally true or false.

            > There are also unprovable
            > hypothesis.

            -- I would say that no hypothesis is provable, at least not in the sense
            that a mathematical theorem is provable. But again, provability and truth
            are entirely different things.

            > For instance, if we made the claim
            > that no two snowflakes are the
            > same, then this can only be true
            > until two identical snowflakes are
            > discovered.

            -- This is another an example of the sort of confusion of truth and
            certainty that I have been complaining about. The claim that "no two
            snowflakes are the same" is either true or false. We can have varying
            degrees of confidence in it. Suppose at first we are quite confident that
            it is true. But later, when we discover two exactly similar snowflakes, our
            confidence goes from "quite high" to "zero". Despite the big change in our
            confidence, its truth-vale remains completely unaffected. It is false, and
            importantly, it always was false. Before, we just didn't know that it was
            false.

            All the best -- Jeremy Bowman

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          • Jeremy Bowman
            ... Me again: -- I didn t say this was an inductive argument , and don t think we should understand it like that. First, I recommend that we reserve the word
            Message 5 of 6 , Aug 4, 2003
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              It was written:

              > > > If H is true then I is true
              > > > I is true
              > > > Therefore H is true

              I replied:

              > > The "argument" above is only
              > > fallacious if we understand it
              > > as a deductive argument. But
              > > we MUST NOT understand it
              > > that way. In a valid deductive
              > > argument the word 'therefore'
              > > expresses the fact that the
              > > premises GUARANTEE the
              > > conclusion, but here the
              > > "premises" just give us a
              > > stronger reason to believe that
              > > the "conclusion" is true.

              Steven D'Aprano wrote:

              > However, your argument that this
              > reasoning is valid for inductive
              > arguments isn't correct.

              Me again:

              -- I didn't say this was an "inductive argument", and don't think we should
              understand it like that.

              First, I recommend that we reserve the word 'induction' for simple
              "enumerative" induction ("the sun has risen every day so far, so it'll
              probably rise again tomorrow"). I agree with Quine's view that enumerative
              induction is a special case of the more general method of hypothesis (i.e.
              the "hypothetico-deductive method").

              Second, I think it's wrong to think of the above sequence as an "argument".
              It is much better understood as a sort of DESCRIPTION of what happens when
              a hypothesis is "confirmed".

              Compare the following sequence of sentences, which describe a test to see
              if a cake is fully cooked:

              1. Push a metal skewer into the thickest part of the cake, withdraw it, and
              see if it is "clean".
              2. It is clean.
              Therefore, the cake is done.

              There is no temptation to think of this sequence of sentences as an
              argument, probably because the "premises" do not contain the key
              information expressed in the "conclusion", about the cake's "being done".
              But it's easy to see how the test works -- it would be an "unlikely
              coincidence" if the cake passed the test, and yet somehow remained
              underdone. We would have to fall back on unusual circumstances to explain
              it -- perhaps the oven does not heat evenly, or the thickest part of the
              cake does not coincide with the point furthest away from the heat source,
              or...

              Similarly, if a hypothesis yields a prediction that turns out to be true,
              and then does it again, and again, it becomes harder and harder to explain
              how the hypothesis itself could be false. Passing a test is an "unlikely
              coincidence" unless the hypothesis is in fact true, or at least
              approximately true.

              Jeremy Bowman

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            • Fredric Weizmann
              Also false is the idea that while inductive evidence may not guarantee some hypothesis with absolute certainty, it increases the probability that the
              Message 6 of 6 , Aug 11, 2003
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                Also false is the idea that while inductive evidence may not guarantee some
                hypothesis with absolute certainty, it increases the probability that the
                hypotheses is true. To take a simple example, it is true that if John is
                immortal, he will be alive next week. However, it is not true that the longer
                John lives the greater the probability that he will live forever. if John is
                alive next week, he is actually closer to the date of his death than he is
                today.

                It is true that that if the implication of a hypothesis is true our
                confidence in the hypothesis is greater, but this is only true
                psychologically, not logically. This is the real "scandal" of Hume's argument
                about induction. Someone on the list (I don't recall who) invoked Popper, and
                Popper had the right of it. All you can really say if the implication of an
                hypothesis is true is that the hypothesis is still viable; however there are
                an indefinite number of other explanations which may have identical
                implications. I am not arguing that we may not have reasonable grounds for
                preferring some hypotheses (or theories) over others, but these grounds
                transcend the simply empirical, at least in its narrower definitions. If I
                believe that Darwinian ideas describe the evolution of life on Earth, it is
                not simply because someone can demonstrate empirically that natural selection
                occurs in some limited circumstances. It is also because those ideas
                integrate so many different kinds of biological data from so many different
                sources. It's really a very elegant, simple and conceptually satisfying
                explanation.

                Fredric Weizmann

                Steven D'Aprano wrote:

                > On Fri, 1 Aug 2003 04:47, Jeremy Bowman wrote:
                >
                > > > One way to test hypotheses it by
                > > > examining test implications;
                > > >
                > > > If H is true then I is true
                > > > I is true
                > > > Therefore H is true
                > > >
                > > > This is a logical fallacy known as
                > > > the 'Fallacy of Affirming the
                > > > Consequent' and is logically invalid.
                > >
                > > My reply:
                > > The "argument" above is only fallacious if we understand it as a
                > > deductive argument. But we MUST NOT understand it that way. In a
                > > valid deductive argument the word 'therefore' expresses the fact that
                > > the premises GUARANTEE the conclusion, but here the "premises" just
                > > give us a stronger reason to believe that the "conclusion" is true.
                >
                > This is an example of a deductive argument that you would agree is
                > fallacious:
                >
                > If a man has two feet then he therefore has two legs.
                > Fred has two legs.
                > Therefore Fred has two feet.
                >
                > It is fallacious because Fred might have lost his feet in an accident,
                > or otherwise have less than two feet. We agree with this.
                >
                > However, your argument that this reasoning is valid for inductive
                > arguments isn't correct. Here is an inductive argument:
                >
                > I've seen 100,000 bus drivers, and they have all had two feet.
                > Hence I use induction to conclude that all bus drivers have two feet.
                > If a person is a bus driver, then inductively she is almost certain to
                > have two feet.
                >
                > And the Fallacy of Affirming the Consequent would be:
                >
                > If a person is a bus driver, then inductively she is almost certain to
                > have two feet.
                > Susan has two feet.
                > Therefore Susan is likely to be a bus driver.
                >
                > Alas for my reasoning ability, Susan is a chemist. Furthermore, bus
                > drivers only make up a tiny minority of two-footed people.
                >
                > Affirming the Consequent is a fallacy whether one is talking about
                > inductive or deductive reasoning. Regardless of whether you use
                > deduction or induction to derive "X implies Y", it is always a fallacy
                > to argue the reverse "Y implies X" without further evidence.
                >
                > > > Science is a matter of observation,
                > > > hypothesis, and degrees of
                > > > confidence - not truth.
                > >
                > > -- Oh yes it is! Consider the sentence 'Everest is higher than the
                > > tallest mountain on Venus'. I have no idea whether this is true or
                > > false -- my confidence in it is zero -- but as a matter of objective
                > > fact, it IS either true or false. Furthermore, it is "absolutely"
                > > true or false.
                >
                > I don't know. How do you define "height"? From sea level? From the
                > lowest point on the planet? From the surrounding plains (if any)? From
                > some arbitrary marker? Depending on how you define height, you may get
                > a completely different answer to the question of which is higher.
                >
                > A few hundred years ago, a statement that a chemist might have asked
                > might have been "Flowers of Sulphur contains more phlogiston than Aqua
                > Regina". Was this statement absolutely true? If it were absolutely
                > false, can we conclude that therefore Aqua Regina contains more
                > phlogiston than sulphur?
                >
                > If X is false, and Not X is also false, then what have we discovered?
                >
                > I doubt that the concept of "height" will ever go the way of phlogiston,
                > but it is conceivable that it might. In which case, neither Everest nor
                > the mountain of Venus will be higher than the other.
                >
                > And even if height doesn't, who knows what will? If we knew, we wouldn't
                > be wasting our time with incorrect scientific theories.
                >
                > --
                > Steven D'Aprano
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