Science Truth 1

8/9/2019 Science Truth 1

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Inside Science The New Scientist

The truth is out there

19 Feb 00

Instruments such as microscopes or telescopes can reveal the

physical world to us, showing a cell's walls or a distant star

system. To examine science itself, you need a different

approach: you must think about thinking. The philosophy of

science uses step-by-step examination to reveal good or bad

science

DOES science tell us the truth? How do we tell the differencebetween science and non-science? If one group of scientists says thatgenetically modified foods are harmless and another says they aredangerous, who should we believe? To answer these questions we

must think about the way scientists reach their conclusions.

Science's goal is to discover the laws of nature, which we assumeexist independently of humans. We find these laws by collecting factsand assembling new theories to explain them. Good science isconducted publicly. Scientists release their results in a way thatallows others to scrutinise them and try to duplicate them or showthat they are wrong. Few people seriously doubt that science works.It has been hugely successful in giving us explanations of the worldaround us. It has the power ultimately to explain all naturalphenomena, even if in practice some problems are proving verydifficult. Science has also allowed us to create technologies such asdrugs to treat cancer or the laser in your CD or MiniDisc player.

WHAT IS SCIENCE?

Testing ideas

No one has yet defined what science is in a way that satisfieseveryone. Science, for example, cannot give absolute proofs of thelaws of nature because, although we can test an idea repeatedly, wecan never be sure that an exception does not exist. Some religiousfundamentalists and TV psychics exploit this difficulty, and claim thatscience is just another set of beliefs, with no more validity than any

other. But while science may not give us absolute truth, this doesn'tmean we must give equal time to magicians and the like. Far from it.

To see why, we need to examine the philosophy of science. Likeother branches of philosophy this involves thinking about thinking(the word originally meant "love of wisdom"). The philosophy oscience uses similar methods to a mathematical proof: a step-by-step examination of assumptions, data and conclusions.


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A classic philosophical question is: "Do I exist? How do I know that Iam not just a program in some immense supercomputer that isfeeding me false sensations about a simulated world?" The Frenchmathematician and philosopher Ren Descartes (1596-1650)answered this question with a proof involving the famous statement,"I think, therefore I am." In other words, the act of doubting that we

exist proves we exist; there must be something that thinks about theproblem of proving existence.

The philosophy of science examines scientific method and askswhat it can tell us. Science deals with empirical knowledge. This isknowledge about the Universe that we acquire by examining how itappears to our senses-enhanced, if necessary, by instruments suchas microscopes or particle accelerators-rather than by sitting andthinking. Empiricism sounds like common sense, but as a way olearning about the world it is comparatively recent. It triumphed inthe scientific revolution of the 16th and 17th centuries, when GalileoGalilei, Robert Boyle, Isaac Newton and others showed that factsgained from empirical observations could revolutionise our picture othe world.

This was where science parted company with magic. Although therewas some overlap at the time-Newton was an enthusiastic alchemist,and mystical texts may have inspired him to think of gravity-there isa basic difference between science and magic. Science involvesrepeatable observations and open publication. There are no hidden or"occult" texts, and when an experiment does not work we do notblame the heavens, the experimenter's lack of spiritual purity or-afavourite of today's TV magicians-"bad vibes" from critical observers.

Empiricism creates its own philosophical problems, however. How do

facts lead to theories and laws of nature? Imagine an experimentinvolving observations of apples. After watching apples fall fromtrees, and verifying that apples will also fall if dropped from thehand, or from the top of a tall building or other tall structures, wereason that a fundamental law is responsible. We call it gravity, andwe predict that when we release an apple or any similar object inmidair, it will fall to the ground.

When we make a prediction based on past experience, we aremoving from statements based on our observations, such as "theapple fell to the ground", to universal statements such as "all applesin the future will fall to the ground". This leap from the singular to

the universal is called inductive reasoning.

Inductive reasoning appeals to common sense, but is logically flawed.The empiricist philosopher David Hume (1711-76) pointed out thatthere can be no logical connection across time. Just becausesomething has happened many times in the past does not prove thatit will happen in the future. Karl Popper (1902-94) pointed out thatscientific verification doesn't actually prove anything. No matter howmany times we record in our notebooks the fact of observing a white


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swan, we get no closer to proving the universal statement that allswans are white. Popper decided that science finds facts not byverifying statements but by falsifyingthem. We may never be ableto prove that all swans are white, but the first time we see a blackswan we can firmly disprove it.

To reason in this way runs counter to intuition (see Figure 1).Logically, however, it is very powerful, and scientists make good useof this power. Popper said that science progresses by testinghypotheses. One scientist holds up a hypothesis for examination- forexample, that gravity bends light waves. Colleagues or rivals thensubject this hypothesis to experimental tests that could show it to befalse. If the hypothesis survives repeated tests, it becomes acceptedas scientific truth.

Popper's ideas provide a link between theory and

experiment. They tell us that no matter how manytests a hypothesis survives, we will never have aphilosophical proof that it is true. Popper wrote:

"There can be no ultimate statements in science . . . and thereforenone which cannot in principle be refuted." This makes a willingnessto accept falsification central to science. Scientists must behaverationally and gracefully, by stating in advance what experimentalobservations would disprove their hypothesis, and if such findings doemerge, accepting that their hypothesis was wrong.

This was important to Popper, who was born in Austria and whose lifewas dominated by struggles against ideologies such as those of NaziGermany, which tolerated no doubts. Popper also contrasted AlbertEinstein's theories of relativity with Karl Marx's theories of history.While Einstein offered his followers tests, such as solar eclipses,which might have disproved his theories, Marxists were undeterredwhen history did not unfold according to prediction. Popper alsoattacked Freudian psychology and Darwinian evolution for what hesaw as their unfalsifiability.

Most working scientists today would go along with the idea ofalsification. But Popper's ideas leave us with several problems:

- Falsification alone cannot distinguish science from non-science. Thehypothesis that reindeer can fly is falsifiable by any scientist with

access to a herd of reindeer, a high cliff and an unusually compliantethics committee. No one, however, would describe the hypothesis asscientific.

- Where do hypotheses come from? One answer might be that theyare merely the application of general principles. For example, theymight be inspired by the principle-named after the medievalphilosopher William of Occam-known as Occam's razor: thesimplest explanations are the best-or that the Universe everywhere

Figure 1


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obeys the same laws of physics. But this brings us back to theproblem of induction.

- Science doesn't progress through falsification. In a strictlyPopperian system, we would have to abandon the laws of chemistryevery time a school student got the wrong result in a chemistry

practical. Clearly, we do not do this. We blame the student's error, orif confronted with a run of anomalous findings, contaminated samplesor faulty instruments. Sometimes this is wrong. Scientists rejectedearly evidence of a hole in the ozone layer over Antarctica because,rather than accepting such unexpected results, they assumed thatthe satellite collecting the data was faulty. This leads us to the nextproblem.

- How to explain scientific revolutions, discoveries which transformunderstanding? Leaps of genius like the theory of evolution bynatural selection, or the theory of relativity, appear to be neither newbricks in the wall of knowledge nor the consequence of falsifying

previous theories.

WAYS OF SEEING

Paradigm shifts

The last question was tackled by Thomas Kuhn (1922-96). In hisbook The Structure of Scientific Revolutions, published in 1962, Kuhnsaid that scientific revolutions need creative thinking of a kind thatcannot grow out of the old order. He dismissed Popper's picture. "Noprocess yet disclosed by the historical study of scientific developmentat all resembles the methodological stereotype of falsification by

direct comparison with nature," he said.

Kuhn suggested that science does not develop by the orderlyaccumulation of facts and theories, but by dramatic revolutions whichhe called paradigm shifts. The worlds before and after a paradigmshift are utterly different-Kuhn's term was "incommensurable"- andexperiments done under the old order may be worthless under thenew.

The switch between before and after is as dramatic as that whichoccurs when looking at a trick gestalt-switchpicture (Figure 2). Youcannot reject one view without replacing it with the other. Such

switches are rare. Kuhn's examples include the Copernicanrevolution, which adopted the idea that the Earth orbited the Sun andnot the other way round, the discovery of oxygen, and Einstein'stheories of relativity. By contrast, most "normal" research takes placewithin paradigms. Scientists accumulate data and solve problems inwhat Kuhn called "mopping-up operations".


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Inevitably, some research throws up findings thatdo not fit the paradigm-perhaps an unexpectedwobble in a planet's orbit around the Sun. InPopper's model these would immediately falsify

the paradigm's central theory. But according to Kuhn, scientistsprefer to cling to old paradigms until a new one is ready. The

anomaly is either discarded or, preferably, worked into the existingparadigm. In this way the elegant model of an Earth-centredUniverse developed in the second century BC by the Greekastronomer Ptolemy accumulated more and more subsidiary orbits toaccount for astronomers' subsequent observations.

After a while, however, the anomalies build up into a crisis oconfidence, and science stalls. Eventually a genius comes up with anew paradigm. Copernicus realised that the observed orbits oplanets made sense when he placed the Sun, rather than the Earth,in the centre of the Solar System. Kuhn said that such leaps happenonly in times of crisis.

In times of paradigm shift, hard scientific facts can becomemeaningless, or change their meaning entirely. For years, scientistsmade measurements on a substance called phlogiston, which theythought was given off when objects burnt. The discovery of oxygenrendered phlogiston meaningless. But chemists could not discoveroxygen until they decided to treat it as a distinct gas. In other words,oxygen had to be invented as well as discovered (Figure 3).

Individual scientists are loath to make such leaps,Kuhn says. The revolution occurs only whenpractitioners under the old paradigm either die orretire. It takes a new generation to carry the torch

of the new paradigm.

Many people have criticised Kuhn. They say his use of the word"paradigm" is imprecise. He chooses his examples overwhelminglyfrom physics, and they say other sciences may change in differentways. And scientists do not seem as reluctant to make paradigmshifts as Kuhn implies. The discovery of DNA's double-helix structureutterly changed the way we think about biology, yet biologistsaccepted it with enthusiasm, replacing a model based on metabolismwith one based on information. Did this make it less than a paradigm

shift?

Likewise the discovery in the late 1980s of new materials thatbecome superconductors at relatively high temperatures was eagerlypursued by scientists. Such breakthroughs must throw into doubtKuhn's distinction between "normal" science-the mopping-up of facts-and revolutionary science.

Finally, Kuhn does not tell us where revolutionary ideas come from.

Figure 2

Figure 3


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We enjoy the folklore of scientific breakthroughs happening byaccident, as with Alexander Fleming and penicillin, or through thework of outsiders such as Einstein. Sadly for Hollywood, such storiesare often myths. Although Einstein was working as a patent officeclerk when he came up with his theories of relativity, he had steepedhimself in contemporary work on physics. Fleming spotted penicillin's

effects because he was an expert in bacteriology, working in alaboratory. In science, chance favours the prepared mind.

Most worrying, if Kuhn is right, science is just a matter of fashionsand a kind of crowd psychology, with nothing to distinguish it frompseudoscience. This problem concerned the Hungarian Imre Lakatos(1922-74), who refined some of Popper and Kuhn's ideas in a waythat makes such a demarcation clear. Instead of "normal" and"revolutionary" science, Lakatos drew a distinction betweenprogressive and degenerative research programmes. Aprogressive research programme is one that leads to the discovery offacts that were previously unknown. An example is Newton's theoryof gravity, which allowed Halley to predict the return of the cometthat now bears his name. A degenerating research programme allowsno such predictions; rather, it must itself be modified to cope withinconvenient facts. Lakatos cites Marxism, which although itdescribes itself as a science has a poor record of predicting a crucialphenomenon-political revolutions.

In progressive research programmes the appearance of awkwardfacts, such as unaccountable wobbles in a planet's orbit, is notnecessarily fatal to the core hypothesis. Scientists can ignore them ithe central hypothesis is still coming up with "unexpected, stunning,predictions", Lakatos says. Revolutions happen gradually asprogressive research programmes replace degenerating ones. But

even in progressive research, facts come after theories.

Theories are clearly made up by humans: they are sociallyconstructed in modern jargon. Does this mean that scientific factsare too? The idea that science is a social construct intrigues manypeople, especially those thinkers described as "postmodernists". If,according to Popper, scientific laws are impossible to verify logicallyand, according to Kuhn, the same findings can mean different thingsbefore and after a scientific revolution, how can science claim to beany more objective than any other cultural pursuit?

No one would deny that culture, values and beliefs shape our choice

of what science to do. Drugs companies began researching AIDSwhen it affected people who could afford to buy medicines ratherthan rural Africans. Military spending on research and development isresponsible for similar biases. Scientists believe, however, that thebasic facts of the Universe are there to be discovered, whatever themotivation for doing so. We spent billions of pounds developingnuclear weapons, and in the process learned a lot about somestrange metal alloys. But we would have found the same facts in arace to build the ultimate ploughshare.


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The "science wars" being fought out between academics, especially inNorth America, question whether this assumption is generally true.Philosophers such as Bruno Latour in Paris study science as a socialphenomenon, and suggest its results are little more than socialrituals.

Some scientists are horrified by the spectre of relativism, whichholds that ideas are not universal or absolute but differ from cultureto culture, individual to individual. A relativist would assert thatscience is only one way of discovering the nature of the physicalworld. The anarchist philosopher Paul Feyerabend (1924-94),perhaps mischievously, took the relativist argument to its logicalconclusion: "There is no idea, however ancient and absurd, that isnot capable of improving our knowledge." In Against Method(1975)he defended the Church's indictment of Galileo. It was rational, hesaid, because there was at the time no reason to suppose thatGalileo's crude telescopes could show the mountains on the Moonthat he claimed to have seen. The Church believed that the Moon wasa perfect smooth sphere quite unlike Earth.

TRUST AND TRUTH

Science and non-science

One vigorous defender of science's special place is the biologist andauthor Richard Dawkins. He notes that when relativist philosophersfly to an international conference on postmodernism, they generallyput their trust in a high-technology airliner rather than a magic

carpet. And, of course, absolute relativism contains its owncontradiction. "Those who tell you there is no absolute truth areasking you not to believe them," says the contemporary philosopherRoger Scruton. "So don't."

One battle in the "science wars" is over Darwin's theory of evolution(see "Evolution under attack"). Some assaults on evolution comefrom a particularly stormy debate over evolutionary psychology or, asit is sometimes called, sociobiology. This attempts to explainpeople's patterns of behaviour-whether it be fear of snakes, or whywe enjoy particular kinds of landscape gardening-solely in terms oevolutionary advantage.

Evolutionary psychology is controversial because it can be used tojustify types of behaviour, such as violence, which are generallyconsidered unacceptable. It is possible to challenge the science oevolutionary psychology without challenging evolution itself.

The phenomenon of consciousness is another problem area.Philosophers and scientists both stake a claim to holding the key tounderstanding consciousness. The fact that some computer scientists

Figure 4


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believe they can create artificial consciousness gives the debate extraspice. But any such project will first have to define what constitutesconsciousness, which is probably a job for philosophy. Science andtechnology can then take over.

Finally, there is the question of exactly what science is. As we have

seen, Popper's falsification criterion alone is not enough todistinguish science from non-science. In fact, if we look at the wholearray of science, from particle physics to cell biology to ecology toengineering, it is hard to find any single practice that they all have incommon. Even openness is not always there: much research is keptsecret for military or commercial reasons.

A way out is to use a concept developed by one of the mostimportant 20th-century philosophers, Ludwig Wittgenstein (1889-1951), that of family resemblance. There are many groups ohuman activities that are impossible to define exactly. For example,it's hard to say what a game is, but when we see a new game we

have no trouble deciding that that's what it is, because of the thingsit shares with other members of the games family. Likewise withscience: all we can say about good science is it has most of thequalities of other activities we call good science, including empiricism,peer reviewand openness to refutation.

Those who work in this family believe that truth is out there. Perhapsnot always in the strictest philosophical sense, but enough forpractical purposes and definitely enough to distinguish science frompropaganda and muddled thinking. Scientists do not need to be shyof admitting that its laws are always provisional. That is not aweakness, but science's greatest strength.

Evolution under attack

THE philosophy of science figures in heated modern debates, suchas the relationship of science and religion. The idea that sciencemust conflict with Christian religion is recent. Newton was adevout if unorthodox Christian who saw science as revealing thewonders of creation, not challenging them. Indeed what is knownas the argument from design-that the world is too intricatelycreated to have arisen by chance- was cited as a scientific proof

that God existed. Darwin's work smashed that consensus.Evolution by natural selection demonstrated that we do not need adivine creator to explain where human beings came from.

Today Darwinism itself is under fire, although the attacks arerarely overtly religious. The target is generally the philosophy ofDarwinian evolution. Some critics cite Popper, who said that thetheory of evolution by natural selection is unscientific because it is


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unfalsifiable. In one sense, this is correct: we cannot rerun thetape of the past 5 billion years. But thousands of biologists everyday test evolution's crucial components and processes. Fame anda large fortune in the biotechnology business await any scientistwho can find a short cut to the slow grind of Darwinian evolution.No one has.

Of course, Darwinism is "only a theory", but this does not meanthat all other theories deserve equal respect.

Further reading:

The Unnatural Nature of Scienceby Lewis Wolpert (Faberand Faber, 1992);

The Structure of Scientific Revolutions by Thomas Kuhn

(University of Chicago Press, 1962); The Social Construction of What?by Ian Hacking (Harvard

University Press, 1999); Unweaving the Rainbowby Richard Dawkins

(Penguin,1998) Confessions of A Philosopherby Brian Magee (Phoenix,

1998)

Michael Cross is a freelance journalist

FromNew Scientist magazine, vol 165 issue 2226, 19/02/2000, page

Copyright New Scientist, RBI Limited 2001

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