Karl Popper’s criterion

Over the last week, I’ve been involved in an argument with another blogger, Justin Martyr, after Larry Niven linked us both to one of his posts. I challenged Justin (on his own blog) over his comments on ID (Intelligent Design), contending that his version was effectively a ‘God-of-the-gaps’ argument. Don’t read the thread – it becomes tiresome.

Justin tended to take the argument in all sorts of directions, and I tended to follow, but it ultimately became focused on Popper’s criterion of falsifiability for a scientific theory. First of all, notice that I use the word, falsifiability (not even in the dictionary) whereas Justin used the word, falsification. It’s a subtle difference but it highlights a difference in interpretation. It also highlighted to me that some people don’t understand what Popper’s criterion really means or why it’s so significant in scientific epistemology.

I know that, for some of you who read this blog, this will be boring, but, for others, it may be enlightening. Popper originally proposed his criterion to eliminate pseudo-scientific theories (he was targeting Freud at the time) whereby the theory is always true for all answers and all circumstances, no matter what the evidence. The best contemporary example is creationism and ID, because God can explain everything no matter what it entails. There is no test or experiment or observation one can do that will eliminate God as a hypothesis. On the other hand, there are lots of tests and observations (that have been done) that could eliminate evolutionary theory.

As an aside, bringing God into science stops science, which is an argument I once had with William Lane Craig and posted as The God hypothesis (Dec.08).

When scientists and philosophers first cited Popper’s criterion as a reason for rejecting creationism as ‘science’, many creationists (like Duane T. Gish, for example) claimed that evolution can’t be a valid scientific theory either, as no one has ever observed evolution taking place: it’s pure conjecture. So this was the first hurdle of misunderstanding. Firstly, evolutionary theory can generate hypotheses that can be tested. If the hypotheses aren’t falsifiable, then Gish would have had a case. The point is that all the discoveries that have been made, since Darwin and Wallace postulated their theory of natural selection, have only confirmed the theory.

Now, this is where some people, like Justin, for example, think Popper’s specific criterion of ‘falsification’ should really be ‘verification’. They would argue that all scientific theories are verified not falsified, so Popper’s criterion has it backwards. But the truth is you can’t have one without the other. The important point is that the evidence is not neutral. In the case of evolution, the same palaeontological and genetic evidence that has proved evolutionary theory correct, could have just as readily proven it wrong. Which is what you would expect, if the theory was wrong.

Justin made a big deal about me using the word testable (for a theory) in lieu of the word, falsification, as if they referred to different criteria. But a test is not a test if it can’t be failed. So Popper was saying that a theory has to be put at risk to be a valid theory. If you can’t, in principle, prove the theory wrong, then it has no validity in science.

Another example of a theory that can’t be tested is string theory, but for different reasons. String theory is not considered pseudo-science because it has a very sound mathematical basis, but it has effectively been stagnant for the last 20 years, despite some of the best brains in the world working on it. In principle, it does meet Popper’s criterion, because it makes specific predictions, but in practice those predictions are beyond our current technological abilities to either confirm or reject.

As I’ve said in previous posts, science is a dialectic between theory and experimentation or observation. String theory is an example, where half the dialectic is missing (refer my post on Layers of nature, May.09) This means science is epistemologically dynamic and leads to another misinterpretation of Popper’s criterion. In effect, any theory is contingent on being proved incorrect, and we find that, after years of confirmation, some theories are proved incorrect depending on circumstances. The best known example would be Newton’s theories of mechanics and gravity being overtaken by Einstein’s special and general theories of relativity. Actually, Einstein didn’t prove Newton’s theories wrong so much as demonstrate their epistemological limitation. In fact, if Einstein’s equations couldn’t be reduced to Newton’s equations (by eliminating the speed of light, c, as a factor) then he would have had to reject them.

Thomas Kuhn had a philosophical position that science proceeds by revolutions, and Einstein’s theories are often cited as an example of Kuhn’s thesis in action. Some science philosophers (Steve Fuller) have argued that Kuhn’s and Popper’s positions are at odds, but I disagree. Both Newton’s and Einstein’s theories fulfill Popper’s criterion of falsifiability, and have been verified by empirical evidence. It’s just that Einstein’s theories take over from Newton’s when certain parameters become dominant. We also have quantum mechanics, which effectively puts them both in the shade, but no one uses a quantum mechanical equation, or even a relativistic one, when a Newtonian one will suffice.

Kuhn effectively said that scientific revolutions come about when the evidence for a theory becomes inexplicable to the extent that a new theory is required. This is part of the dialectic that I referred to, but the theory part of the dialectic always has to make predictions that the evidence part can verify or reject.

Justin also got caught up in believing that the methodology determines whether a theory is falsifiable or not, claiming that some analyses, like Bayesian probabilities for example, are impossible to falsify. I’m not overly familiar with Bayesian probabilities but I know that they are a reiterative process, whereby a result is fed back into the equation which hones the result. Justin was probably under the impression that this homing into a more accurate result made it an unfalsifiable technique. But, actually, it’s all dependent on the input data. Bruce Bueno de Mequita, whom New Scientist claim is the most successful predictor in the world, uses Bayesian techniques along with game theory to make predictions. But a prediction is falsifiable by definition, otherwise it’s not a prediction. It’s the evidence that determines if the prediction is true or false, not the method one uses to make the prediction.

In summary: a theory makes predictions, which could be right or wrong. It’s the evidence that should decide whether the theory is right or wrong; not the method by which one makes the prediction (a mathematical formula, for example); nor the method by which one gains the evidence (the experimental design). And it’s the right or wrong part that defines falsifiability as the criterion.

To give Justin due credit, he allowed me the last word on his blog.

Footnote: for a more esoteric discussion on Steve Fuller’s book, Kuhn vs. Popper: The Struggle for the Soul of Science, in a political context, I suggest the following. My discussion is far more prosaic and pragmatic in approach, not to mention, un-academic.

Addendum: (29 March 2010) Please read April's comment below, who points out the errors in this post concerning Popper's own point of view.

Addendum 2: This is one post where the dialogue in the comments (below) is probably more informative than the post, owing to contributors knowing more about Popper than I do, which I readily acknowledge.

Addendum 3: (18 Feb. 2012) Here is an excellent biography of Popper in Philosophy Now, with particular emphasis on his contribution to the philosophy of science.

 

Speciation: still one of nature’s great mysteries

First of all a disclaimer: I’m a self-confessed dilettante, not a real philosopher, and, even though I read widely and take an interest in all sorts of things scientific, I’m not a scientist either. I know a little bit more about physics and mathematics than I do biology, but I can say with some confidence that evolution, like consciousness and quantum mechanics, is one of nature’s great mysteries. But, like consciousness and quantum mechanics, just because it’s a mystery doesn’t make it any less real. Back in Nov.07, I wrote a post titled: Is evolution fact? Is creationism myth?

First, I defined what I meant by ‘fact’: it’s either true or false, not something in between. So it has to be one or the other: like does the earth go round the sun or does the sun go round the earth? One of those is right and one is wrong, and the one that is right is a fact.

Well, I put evolution into that category: it makes no sense to say that evolution only worked for some species and not others; or that it occurred millions of years ago but doesn’t occur now; or the converse that it occurs now, but not in the distant past. Either it occurs or it never occurred, and all the evidence, and I mean all of the evidence, in every area of science: genetics, zoology, palaeontology, virology; suggests it does. There are so many ways that evolution could have been proven false in the last 150 years since Darwin’s and Wallace’s theory of natural selection, that it’s just as unassailable as quantum mechanics. Natural selection, by the way, is not a theory, it’s a law of nature.

Now, both proponents and opponents of evolutionary theory often make the mistake of assuming that natural selection is the whole story of evolution and there’s nothing else to explain. So I can confidently say that natural selection is a natural law because we see evidence of it everywhere in the natural world, but it doesn’t explain speciation, and that is another part of the story that is rarely discussed. But it’s also why it’s one of nature’s great mysteries. To quote from this week’s New Scientist (13 March, 2010, p.31): ‘Speciation still remains one of the biggest mysteries in evolutionary biology.’

This is a rare admission in a science magazine, because many people believe, on both sides of the ideological divide (that evolution has created in some parts of the world, like the US) that it opens up a crack in the scientific edifice for creationists and intelligent design advocates to pull it down.

But again, let’s compare this to quantum mechanics. In a recent post on Quantum Entanglement (Jan.10), where I reviewed Louisa Gilder’s outstanding and very accessible book on the subject, I explain just how big a mystery it remains, even after more than a century of experimentation, verification and speculation. Yet, no one, whether a religious fundamentalist or not, wants to replace it with a religious text or any other so-called paradigm or theory. This is because quantum mechanics doesn’t challenge anything in the Bible, because the Bible, unsurprisingly, doesn’t include anything about physics or mathematics.

Now, the Bible doesn’t include anything about biology either, but the story of Genesis, which is still a story after all the analysis, has been substantially overtaken by scientific discoveries, especially in the last 2 centuries.

But it’s because of this ridiculous debate, that has taken on a political force in the most powerful and wealthy nation in the world, that no one ever mentions that we really don’t know how speciation works. People are sure to counter this with one word, mutation, but mutations and genetic drift don’t explain how genetic anomalies amongst individuals lead to new species. It is assumed that they accumulate to the point that, in combination with natural selection, a new species branches off. But the New Scientist cover story, reporting on work done by Mark Pagel (an evolutionary biologist at the University of Reading, UK) challenges this conventionally held view.

To quote Pagel: “I think the unexamined view that most people have of speciation is this gradual accumulation by natural selection of a whole lot of changes, until you get a group of individuals that can no longer mate with their old population.”

Before I’m misconstrued, I’m not saying that mutation doesn’t play a fundamental role, as it obviously does, which I elaborate on below. But mutations within individuals don’t axiomatically lead to new species. This is a point that Erwin Schrodinger attempted to address in his book, What is Life? (see my review posted Nov.09).

Years ago, I wrote a letter to science journalist, John Horgan, after reading his excellent book The End of Science (a collection of interviews and reflections by some of the world’s greatest minds in the late 20th Century). I suggested to him an analogy between genes and environment interacting to create a human personality, and the interaction between speciation and natural selection creating biological evolution. I postulated back then that we had the environment part, which was natural selection, but not the gene part of the analogy, which is speciation. In other words, I suggested that there is still more to learn, just like there is still more to learn about quantum mechanics. We always assume that we know everything that there is to know, when clearly we don’t. The mystery inherent in quantum mechanics indicates that there is something that we don’t know, and the same is true for evolution.

Mark Pagel’s research is paradigm-challenging, because he’s demonstrated statistically that genetic drift by mutation doesn’t give the right answers. I need to explain this without getting too esoteric. Pagel looked at the branches of 101 various (evolutionary) trees, including: ‘cats, bumblebees, hawks, roses and the like’. By doing a statistical analysis of the time between speciation events (the length of the branches) he expected to get a Bell curve distribution which would account for the conventional view, but instead he got an exponential curve.

To quote New Scientist: ‘The exponential is the pattern you get when you are waiting for some single, infrequent event to happen… the length of time it takes a radioactive atom to decay, and the distance between roadkills on a highway.’

In other words, as the New Scientist article expounds in some detail, new species happen purely by accident. What I found curious about the above quote is the reference to ‘radioactive decay’ which was the starting point for Erwin Schrodinger’s explanation of mutation events, which is why mutation is still a critical factor in the whole process.

Schrodinger went to great lengths, very early in his exposition, to explain that nearly all of physics is statistical, and gave examples from magnetism to thermal activity to radioactive decay. He explained how this same statistical process works in creating mutations. Schrodinger coined a term, ‘statistico-deterministic’, but in regard to quantum mechanics rather than physics in general. Nevertheless, chaos and complexity theory reinforce the view that the universe is far from deterministic at almost every level that one cares to examine it. As the New Scientist article argues, Pagel’s revelation supports Stephen Jay Gould’s assertion: ‘that if you were able to rewind history and replay the evolution on Earth, it would turn out differently every time.’

I’ve left a lot out in this brief exposition, including those who challenge Pagel’s analysis, and how his new paradigm interacts with natural selection and geographical separation, which are also part of the overall picture. Pagel describes his own epiphany when he was in Tanzinia: ‘watching two species of colobus monkeys frolic in the canopy 40 metres overhead. “Apart from the fact that one is black and white and one is red, they do all the same things... I can remember thinking that speciation was very arbitrary. And here we are – that’s what our models are telling us.”’ In other words, natural selection and niche-filling are not enough to explain diversification and speciation.

What I find interesting is that wherever we look in science, chance plays a far greater role than we credit. It’s not just the cosmos at one end of the scale, and quantum mechanics at the other end, that rides on chance, but evolution, like earthquakes and other unpredictable events, also seems to be totally dependent on the metaphorical roll of the dice.

Addendum 1 : (18 March 2010)

Comments posted on New Scientist challenge the idea that a ‘bell curve’ distribution should have been expected at all. I won’t go into that, because it doesn’t change the outcome: 78% of ‘branches’ statistically analysed (from 110) were exponential and 0% were normal distribution (bell curve). Whatever the causal factors, in which mutation plays a definitive role, speciation is as unpredictable as earthquakes, weather events and radio-active decay (for an individual isotope).

Addendum 2: (18 March 2010)

Writing this post, reminded me of Einstein’s famous quote that ‘God does not play with dice’. Well, I couldn’t disagree more. If there is a creator-God (in the Einstein mould) then first and foremost, he or she is a mathematician. Secondly, he or she is a gambler who loves to play the odds. The role of chance in the natural world is more fundamental and universally manifest than we realise. In nature, small variances can have large consequences: we see that with quantum theory, chaos theory and evolutionary theory. There appears to be little room for determinism in the overall play of the universe.

The world badly needs a radical idea

Over the last week, a few items, in the limited media that I access, have increased my awareness that the world needs a new radical idea, and I don’t have it. At the start of the 21st Century we are like a species on steroids, from the planet’s point of view, and that’s not healthy for the planet. And if it’s not healthy for the planet, it’s not healthy for us. Why do so few of us even seem to be aware of this?

It started with last week’s New Scientist’s cover story: Earth’s Nine Lives; whereby an environmental journalist, Fred Pearce, looks at 9 natural parameters that give an indication of the health of the planet from a human perspective. By this, I mean he looks at limits set by scientists and how close we are to them. He calls them boundaries, and they are all closing or already passed, with the possible exception of one. They are: ocean acidity; ozone depletion; fresh water; biodiversity; nitrogen and phosphorous cycles; land use; climate change; atmospheric aerosol loading and chemical pollution.

Out of these, ozone depletion seems to be the only one going in the right direction, and, according to Pearce, three of them, including climate change, have actually crossed their specified boundaries already. But, arguably, the most disturbing is fresh water where he believes the boundary will be crossed mid-century. It’s worth quoting the conclusion in its entirety.

However you cut it, our life-support systems are not in good shape. Three of nine boundaries - climate change, biodiversity and nitrogen fixation - have been exceeded. We are fast approaching boundaries for the use of fresh water and land, and the ocean acidification boundary seems to be looming in some oceans. For two of the remaining three, we do not yet have the science to even guess where the boundaries are.

That leaves one piece of good news. Having come close to destroying the ozone layer, exposing both ourselves and ecosystems to dangerous ultraviolet radiation, we have successfully stepped back from the brink. The ozone hole is gradually healing. That lifeline has been grabbed. At least it shows action is possible - and can be successful.

The obvious common denominator here is human population, which I’ve talked about before (Living in the 21st Century, Sep.07 and more recently, Utopia or dystopia, Sep.09; and my review of Tim Flannery’s book, The Weathermakers, Dec. 09).

In the same week (Friday), I heard an interview with Clive Hamilton, who is Charles Sturt Professor of Public Ethics at the Centre for Applied Philosophy and Public Ethics at the Australian National University, Canberra. He’s just written a book on climate change and despairs at the ideological versus scientific struggle that is taking place globally on this issue. He believes that the Copenhagen summit was actually a backward step compared to the Kyoto protocol.

Then, today (Saturday) Paul Carlin sent me a transcript of an interview with A.C. Grayling, who is currently visiting Australia. The topic of the interview is ‘Religion in its death throes’, but he’s talking about religion in politics rather than religion in a genuinely secularised society.

He’s looking forward to a time when religion is a personal thing rather than a political weapon, that effectively divides people and creates the ‘us and them’ environment we seem to be in at the moment. Australia is relatively free from this, but the internet and other global media means we are not immune. In fact, people have been radicalised in this country, and some of them are now serving jail sentences as a consequence.

To quote Grayling, predicting a more tolerant future:

‘And people who didn't have a religious commitment wouldn't mind if other people did privately and they wouldn't attack or criticise them.

So there was an unwritten agreement that the matter was going to be left quiet. So in a future where the religious organisations and religious individuals had returned to something much more private, much more inward looking, we might have that kind of public domain where people were able to rub along with one another with much less friction than we're seeing at the moment.’

To a large extent, I feel we already have that in Australia, and it’s certainly a position I’ve been arguing for, ever since I started this blog.

But Grayling also mentions climate change, when asked by his interviewer, Leigh Sales, but hints, rather than specifies, that a debate between a science expert on climatology and a so-called climate-change-sceptic would not be very helpful, because they are arguing from completely different places. One is arguing from scientific data and accepted peer-reviewed knowledge and the other is arguing from an ideological position because he or she sees economic woe, job losses and political hardship. It’s as if climate change is a political position and not a scientific-based reality. It certainly comes across that way in this country. As Clive Hamilton argues: people look out their windows and everything looks much the same, so why should I believe these guys in their ivory towers, who create dramas for us because it’s how they make their living. I’m not being cynical – many people do actually think like that.

But this is all related to the original topic formulated by the New Scientist article – it goes beyond climate change - there are a range of issues where we are impacting the planet, and in every case it’s the scientists faint, but portentously reliable voices, who are largely ignored by the politicians and the decision-makers of the world who set our economic course. And that’s why the world badly needs a radical idea. Politicians, the world over, worship the god of economic growth – it’s the mantra heard everywhere from China to Africa to Europe to America to Australia. And economic growth propels population growth and all the boundary pushing ills that the planet is currently facing.

The radical idea we so badly need is an alternative to economic growth and the consumer driven society. I really, badly wish 2 things: I wish I was wrong and I wish I knew what the radical idea was.