The Scientific Method

A tool for discovering and investigating our world

Friday, July 20, 2012

At the Reason Rally in Washington in March of this year, one lady carried a sign that read, "Want to argue for Creationism? Write up your evidence. Have it peer-reviewed. Then collect your Nobel Prize."

This sign concisely expresses an important concept. When a religious person argues that we all follow a set of beliefs, that science has no monopoly on the truth, I would answer that, Yes, I believe in certain things. I can't personally confirm things like the existence of galaxies, the age of the Earth or the universe, the fact that the universe is expanding, and that this expansion is accelerating at a dizzying rate. Yes, I believe all these things without confirming them myself. They were discovered by people using the scientific method. The components working together to form the scientific method, evolving mainly over the last five centuries, include

1. A reliance on observation, even observations that don't seem to comport with common sense, e.g. the observations on which quantum theory is built.

2. Experiments designed to prevent biases on the part of the researcher from skewing the results. In research involving human subjects, the "double blind" method has become standard procedure.

3. Peer review. Other scientists in the same field must be able to replicate the experimental results. “And concerning his scientific papers, it is only in attempts to explain his work to somebody who has not done it that he can acquire the discipline of clear and reasoned communication which, too, is part of scientific method.”(Popper, Chap 23)

Replicate the results. Especially when a big paradigm-changing finding is made, it must undergo the attempt by other scientists to replicate the results. Cold fusion, anyone? These claims went through a cold shower instead when other scientists could not reproduce the findings in their own labs.

Scientific objectivity depends on this social nature of the endeavor. Others must weigh in on one’s work. Articles published in a scientific journal, which subjects the material to peer review, receive the imprimatur of acceptance as a scientific finding. The publication of an article makes it available to the scientific community. If they find it useful it then enters the general body of scientific knowledge, until some later findings wholly or partially supplant these findings.

4. Theory and observation. A scientist invents a hypothesis which can be tested, and then submits it to practical tests (This description is a little too pat. In real life the process is usually more chaotic). Theories must give way if new evidence falsifies them.

All scientific findings therefore remain tentative, as "just theories". Even Newton's findings about gravity were partially supplanted by some of Einstein's theories. “It was one of the greatest achievements of our time when Einstein showed that, in light of experience, we may question and revise our presuppositions regarding even space and time.”(Popper, Chap 23)

Frauds such as the "Piltdown Man" hoax and mistakes in theory, such as the underlying causes of ulcers, get corrected, because science is in part a competitive endeavor—scientists succeed when they find errors in previously accepted ideas.

5. Scientific knowledge advances in a cumulative way. Popper and Thomas Kuhn agreed on the essentially cumulative nature—not of scientific theory, but of the facts which a fruitful theory yields. Popper provided insights on how scientific knowledge accumulates through a process akin to natural selection, evolving in step by step fashion.

Kuhn has shown how science sometimes takes great leaps forward, advances that shift our paradigms, such as the Theory of Special Relativity. These too were built on the work of scientists who came before. Thus, Newton built upon the work of Kepler; Einstein built upon the work of Lorentz; Darwin built upon the work of Lyall, Lamarck and Malthus.

Eventually the old paradigm fades, but the facts it arrived at remain to accumulate and inform humanity. (Pat Duffy Hutcheon, Popper and Kuhn on the Evolution of Science)

When one individual contributes a significant improvement to this method, he moves us forward in an important way and deserves our kudos. Galileo contributed to our focus on the central importance of evidence. In the 1950s the Austrian Karl Popper contributed the notion of falsifiability to the scientific method. At least he was the first to name the concept falsifiability, and to focus on its importance. Carl Sagan gives us a hilarious, devastating example of this falsifiability concept in his story of the invisible dragon—which in turn casts doubt upon the heart of religious belief. If people believe in an invisible dragon, a flying spaghetti monster, Thor, or Jehovah, and the believers cannot describe any observation which, if made, would discredit (falsify) such belief, then that belief is not falsifiable and does not belong in the body of scientific knowledge.

Karl Popper laid out his tenet of falsifiability in the books The Logic of Scientific Discovery and The Philosophy of Science. It was the conscious, purposeful search for falsifications, and the survival of theories in the face of them, that allowed science to proceed and objective knowledge to grow. The reason science gave you knowledge you can rely on was that science itself wasn’t sure. Science wasn’t the name for knowledge that had been proved true, it was the name for guesses that could be, but haven’t yet been, proved false.

Popper drew on the earlier work of David Hume and his “problem of induction”. The picture must always be haunted by a small, permanent ghost of uncertainty. In the textbook example, if the law stated that “All swans are white” you could count white swans for centuries but still not know that all swans were white, not for sure. Science relies on an asymmetry to decide on which theories are correct: no number of white swans could tell you that all swans were white, but a single black swan could tell you that they weren’t. (Gopnik)

Stuart Firestein, a professor of Neuroscience, has published a book about science and the experience of dealing with ignorance while working at the edge of what is known. Ignorance: How It Drives Science. Description from

Says Firestein, more often than not, science is like looking for a black cat in a dark room, and there may not be a cat in the room. The process is more hit-or-miss than you might imagine, with much stumbling and groping after phantoms. But it is exactly this "not knowing," this puzzling over thorny questions or inexplicable data . . . the driving force of science. Firestein shows how scientists use ignorance to program their work, to identify what should be done, what the next steps are, and where they should concentrate their energies. And he includes a catalog of how scientists use ignorance, consciously or unconsciously—a remarkable range of approaches that includes looking for connections to other research, revisiting apparently settled questions, using small questions to get at big ones, and tackling a problem simply out of curiosity.

And sometimes (like with the experiments on luminiferous aether) , failure can prove as interesting and move science forward as much as a successful experiment.

The book concludes with four case histories—in cognitive psychology, theoretical physics, astronomy, and neuroscience—that provide a feel for the nuts and bolts of ignorance, the day-to-day battle that goes on in scientific laboratories and in scientific minds with questions that range from the quotidian to the profound.

Also from the Amazon page, regarding climate change and science, "If more people embraced the seductive appeal of uncertainty, he says, it might take some acrimony out of our public debates." —Sandra Blakeslee, New York Times

I trust in knowledge found through this scientific method, not in the Bible. One set of ideas allows for revision, the other remains fixed. One set of ideas has a vast body of knowledge at its command which it can build on in a cumulative way; the other does not. More of our science curriculum at all levels, grade school through college, should devote time to learning about the scientific method.

Popper is quoted here from “The Open Society and its Enemies”. “A Pilgrimage to Popper” by Adam Gopnik, appearing in The New Yorker issue of 04-01-2002 provided the material about the black and white swans.

Addendum August 11, 2015: Max Planck said that science advances one funeral at a time. And what he meant was that old theories may never die, but old theorists do, and when they do, they take their theories with them. A new generation is always more comfortable dispensing with old ideas than are their predecessors.

So why does it take so long for many canards in the fields of medicine and psychiatry to die?

Addendum Feb 27, 2016: has put together a handy reference sheet they call A Rough Guide to Spotting Bad Science.
Essential !!

Addendum Apr 24, 2016: The use of the scientific method, including the process of peer review, that produced our knowledge of climate change and climate science. Laid out by Michael Mann of Penn State.

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