Karl Popper is generally regarded as one of the greatest philosophers of science of the 20th century. The Stanford Encyclopedia of Philosophy summarises his view of science thus, Popper …
… repudiates induction and rejects the view that it is the characteristic method of scientific investigation and inference, substituting falsifiability in its place. It is easy, he argues, to obtain evidence in favour of virtually any theory, and he consequently holds that such ‘corroboration’, as he terms it, should count scientifically only if it is the positive result of a genuinely ‘risky’ prediction, which might conceivably have been false. For Popper, a theory is scientific only if it is refutable by a conceivable event. Every genuine test of a scientific theory, then, is logically an attempt to refute or to falsify it, and one genuine counter-instance falsifies the whole theory. In a critical sense, Popper’s theory of demarcation is based upon his perception of the logical asymmetry which holds between verification and falsification: it is logically impossible to conclusively verify a universal proposition by reference to experience (as Hume saw clearly), but a single counter-instance conclusively falsifies the corresponding universal law. In a word, an exception, far from ‘proving’ a rule, conclusively refutes it.
From that viewpoint a theory that increasing atmospheric carbon dioxide will produce global warming can be tested by comparing global temperature with CO
2 levels. If CO
2 goes up and temperature does not then the theory is refuted.
It is a useful theory because it is a falsifiable theory. If it doesn’t hold true you don’t necessarily have to toss it in the bin. You can take it back to the drawing board and tinker with it and see if there is a related theory that better explains the facts. To be useful the new theory must also be capable of disproof. A theory, for example, that predicts that increasing CO
2 will produce temperature rise, temperature decrease, increased rainfall and drought is a tough one to falsify.
The University of Michigan brings us news of a study that will soon be published in the journal Global Change Biology. Be afraid, be very afraid because it is clear from the study that “scientists may be underestimating the impacts of climate change on animals and plants because much of the harm is hidden from view.”
I will quote selectively, you may feel obliged to see if I have distorted the tale by reading the whole saga <HERE>.
Between 1978 and 2009, Finnish scientists used light traps at night to catch 388,779 moths from 456 species. Eighty of the most abundant species were then analyzed.
Hunter used a statistical technique called time series analysis to examine how various ecological forces, including climate, affected per capita population growth.
The study analyzed populations of 80 moth species and found that 90 percent of them were either stable or increasing throughout the study period, from 1978 to 2009.
There is an obvious conclusion to be drawn here and the authors thought of it …
On one level, the results can be viewed as a good news climate story: In the face of a rapid environmental change, these moths appear to be thriving, suggesting that they are more resilient than scientists had expected, Hunter said.
… and rejected it. In favour of …
The findings have implications that reach beyond moths in Lapland.
If unknown ecological forces are helping to counteract the harmful effects of climate change on these moths, it’s conceivable that a similar masking of impacts is happening elsewhere. If that’s the case, then scientists are likely underestimating the harmful effects of climate change on animals and plants, Hunter said.
And they called it science …