True, False, or Not Sure? Philosophy of Science in the 21st century

Printer-friendly versionPrinter-friendly version Share this

Whatever happened to objective reality? Why is climate change so hard to prove?

Big Ideas: 
  • How do we proceed when we can never know anything for sure?

Many of us were brought up on the idea of an objective reality determined, at least provisionally, by experiments and analyses performed by a closed but international group of scientists, freely exchanging ideas, testing and refuting hypotheses. This loose federation of scientists formed Michael Polanyi's "Republic of Science"1 (1962) and they were guided by principles described by Robert Merton2 (1942) to be "scepticism, universalism, communalism and disinterestedness". Hypotheses tested widely enough and found not to be at variance with current evidence became theories. A crucial property of any theory was that it should logically be falsifiable by new evidence, as stated by Karl Popper3around 1960. At some point in time, evidence at variance with an accepted theory can lead to a revolution first and eventually a paradigm shift, a process described by Thomas Kuhn3. While a discipline's fundamental claims are shifting from one perspective to another, groups of scientists are attempting to disprove each other until one theory is generally agreed upon, a condition that must be fulfilled for science to progress. All theories are provisional, because they are all based on observation and all observations have limitations, either in extent or in the accuracy of the measurements, which should always be expressed in terms of probabilities. The next revolution is always waiting around the corner. This is "Normal Science".

Fast forward to 1993, when Funtowicz and Ravetz4 defined "Post-Normal Science", where "facts are uncertain, values in dispute, stakes are high and decisions urgent". Post normal science recognizes that multiple perspectives can and should be incorporated in order to solve complex problems. Scientists bear a much higher burden of responsibility for communication both amongst themselves and with a wide audience outside science. The continuing turmoil over climate change is a perfect example of post-normal science, but the same features are seen in the debate over energy supplies, GM foods etc. In some ways, individual engineers and medical professionals have always done "post-normal science".

Let me contrast two recent "discoveries" to illustrate the differences. The first is the discovery of neutrino oscillations5 (normal science) and the second is the discovery of anthropogenic climate change (post-normal science). In the first I had a strong personal stake, which I shared with a few hundred other physicists, but almost no-one else. In the second I also have a strong personal stake, but so do you, and so does everyone else on the planet.

Contrasting Normal and Post Normal Science

The effort to prove or disprove the existence of neutrino oscillations (you don't need to understand what neutrinos are or why/how they oscillate to get the gist of this argument) followed Merton's norms perfectly. Everyone involved was always sceptical, right to the end. The subject had universal implications, as neutrinos have played a part in ever major event in the universe from the Big Bang to the explosion of supergiant stars that produced the heavy elements are fundamental to our make up and our Earth. It was a big communal effort, involving many groups of physicists from around the world. We were disinterested, for although everyone has biases, we worked hard to remove those from our experiments and analyses (which were "blind", as in medical trials), and ultimately, disproving the existence of neutrino oscillations would have been almost as big a deal as proving they do exist. The burden of proof, one way or the other, lay with the scientists, and no-one else: the closed republic of science. Time was not really of essence, although politicians and funding agencies were often anxious about delays and costs. Failure to determine the answer one way or the other would have primarily been of consequence to the careers of the scientists involved. Either way, the world would have gone on pretty much the same way whatever the result. The universe may depend on neutrinos, but not of our understanding of them.

Now consider the discovery, if that is the right term, of anthropogenic climate change, the global disruption of the climate by human activities. To start with, no-one would claim this to be established as absolute truth or fact. The IPCC puts the probability at 90%6.  That the climate is changing significantly is as close to 100% certain as makes no difference (ask any polar bear or Australian farmer). I would be less surprised if the 50-year hunt for neutrino oscillations proved to be all in error, than if the climate was shown not to be changing. The human component is another matter. But the burden of proof is different, because the implications are enormous and the timescale for action very short. This is not neutrino oscillations, because much more hangs on the outcome than the careers of a few physicists. Neither is it a court of law, where our society has decided that convicting an innocent person is a much worse error than allowing a guilty one to go free. Here it may be the other way around; taking action that proves ultimately not to be necessary would likely be much less costly than not taking necessary action. Reducing our footprint on this planet is in all probability a good idea even if the climate proved to be stable7. And because the implications are so enormous, everyone has to be involved: scientists, governments, businesses, individuals. And no-one, not even the scientists, are disinterested, because we have nowhere else to go and children born now will have to live in the last decades of this century. That makes the decision-making much more complicated, and it would be even if the facts were universally agreed upon. But they are not, because "facts" rely on making predictions about the future behaviour of a very complex system, which is intrinsically hard, and depends on mathematical models, which will always be imperfect representations of reality. We don't even have a good handle on the uncertainties, as the prospect of runaway positive feedbacks means that the outcomes could be well outside the means and standard deviations presented by the IPCC. (Even if we did know the probabilities of each outcome, we as a species seem to have trouble dealing with probabilities rather than "facts", and scientists tie themselves in knots explaining them. The timescale is a further complicating factor. Because radical climate change seems to be occurring on a timescale of a few decades - shorter than one human life - we don't have the luxury of taking the time rigorously to test the theory and to achieve worldwide consensus. Welcome to post-normal science.

For more details, ref. 8 is a great read.


Thanks for posting! Very good

Thanks for posting! Very good information. I love to debate philosophy!

Post new comment

Please note that these comments are moderated and reviewed before publishing.

The content of this field is kept private and will not be shown publicly.
By submitting this form, you accept the Mollom privacy policy.

a place of mind, The University of British Columbia

C21: Physics Teaching for the 21st Century
UBC Department of Physics & Astronomy
6224 Agricultural Road
Vancouver, BC V6T 1Z1
Tel 604.822.3675
Fax 604.822.5324

Emergency Procedures | Accessibility | Contact UBC | © Copyright The University of British Columbia