All scientific models are tentative.

Why don’t more scientists become politicians? Scientists change their mind in the face of new evidence. To the media, that gets tagged as the mortal sin of “backflipping”.

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In short…

No scientific model can ever be considered proven with absolute certainty. There is always a possibility that falsifying evidence will be found. This is unlikely, though, if the model has been supported by multiple independent lines of evidence.

Science advances through tentative answers to a series of more and more subtle questions which reach deeper and deeper into the essence of natural phenomena.

Attributed to Louis Pasteur, French  microbiologist.

In what sense are models tentative?

Scientists know that any scientific model is likely to be confronted by new evidence that potentially falsifies it. They use the model in full knowledge of the fact that it may be replaced by a better model at any time.

What does the tentative nature of models mean for science?

Scientists should never claim that their models are ‘proven’ because they know that all models are tentative.

The foundations of all scientific models are always being questioned. Up-and-coming scientists know that if they can find holes in a scientific model and develop a new one, they will achieve a high profile in the scientific community.

This does not mean that scientists can have no confidence in their models. In many scientific fields, models have been tested and refined to such an extent that any errors are likely to be minor. If evidence that appears to falsify a model turns up, the new evidence needs to be scrutinised carefully, especially if the model is a well-established one. Scientists often fiercely defend their models in the face of contradictory evidence, but in the end, valid evidence must prevail.

Why models are tentative

The tentative nature of scientific models follows from two characteristics of models; first, they must be falsifiable and second, they are indeed models, not the real thing. A model survives only as long as it isn’t falsified, and even though the model may have been supported by multiple independent lines of evidence, there’s always a chance that falsifying evidence will turn up.

Examples

• Marine researchers have expressed concern about the effects of global warming on the future of coral reefs because increasing sea temperatures cause coral bleaching. Bleaching happens because the corals expel the algae that live within their cells when temperatures rise. Recent research has tentatively shown that some algae may be able to adapt to temperature rises, and consequently improve the chances that corals can survive.
• In 1976, British theoretical physicist Stephen Hawking discovered the Black Hole Information Paradox – not just matter, but information should disappear in a black hole. Many of his colleagues argued that he was wrong and there was a prolonged scientific ‘war‘ between the protagonists. In 2004, Hawking produced a solution to the paradox, but rather than support his earlier stance, it showed that he had been wrong, and the opposite was the case – information is not destroyed in black holes. Hawking duly paid a bet that he had arranged with John Preskill in 1997. Other physicists are unconvinced, and the status of the paradox is still uncertain.
• In early 2012, a paper published in the journal Nature reported that Himalayan glaciers were losing ice much more slowly than previously measured. The data used for the paper came from the Gravity Recovery and Climate Experiment (GRACE) satellites which measure the gravitational pull of the ice sheets. In July 2012, Nature Climate Change published another paper based on measurements recorded on the ground. This paper shows that the glaciers are shrinking rapidly and that the rate of retreat is actually accelerating. It seems that the GRACE satellites cannot distinguish between the gravitational pull of ice and water and thus are not suited to non-polar glacial measurements. ECOS has the story here.

Further reading

Where’s the proof in science? There is none at The Conversation.

The ATLAS image is from ATLAS news. This ATLAS experiment was conducted to test whether the Higgs boson can decay into fermions as well as into bosons, as predicted by the Standard Model of particle Physics

This is one of ScienceOrNot’s Hallmarks of science. See them all here.

This page checked and updated: 2013/12/02