Monday, November 30 , 2015, 5:07 pm | Fair 58º

Victor Dominocielo: How Do We Know What We Know in Science?

By Victor Dominocielo |

Why is science better than our individual observations and opinions or even thousands of observations and opinions over thousands of years? The short answer is that you and I can be completely wrong and pass those wrong explanations down through the centuries.

Several different cultures throughout history looked at the night sky and concluded that it was a dome and that the stars were pinholes of light from heaven on the other side. For 3,000 years, we explained bloodletting as helping to balance the four humors in our bodies and return us to good health. Today, every single one of us makes the same mistake Ptolemy did in the second century when we say, “The sun is setting,” which implies that the sun is moving around the Earth.

Scientifically minded individuals worked in isolation when our species began farming and ranching some 10,000 years ago. As villages became cities, science-minded people were able to experiment and learn together in small groups, and as universities were established in different cultures, various scientific standards were produced. These different scientific standards had to deal with the prevailing politics and religions of their cultures, and this remains true even today.

So it was only about 150 years ago when global industrialization, travel and communication (telegraph) became reliable and routine enough that scientists were able to begin a network of standardization for the scientific process. Experiments by Louis Pasteur in France were communicated, replicated and verified around the world as the germ theory of disease finally displaced the defunct theory of the four humors. Guglielmo Marconi in Italy shared the 1909 Nobel Prize for wireless telegraphy with Karl Braun of Germany.

As the world became a smaller place, scientists increasingly shared their work and a standard methodology for scientific investigation developed. As Neil deGrasse Tyson said at the beginning of the new Cosmos series:

“Test ideas by experiment and observation.
Build on those ideas that pass the test;
Reject the ones that fail.
Follow the evidence wherever it leads and
Question everything.”

This worldwide, multicultural standard of a well-controlled scientific experiment is used when anyone wants their explanations for cause and effect to go beyond their personal beliefs and whimsical suppositions. Experiments and the repetition of experimental results is the key to this scientific standard. Experiments, and especially experiments involving people, must be arranged with specific controls in order to get reliable results. For example, in testing a new drug, experiments would have to include a significant group size and randomly chosen subjects.

Ideally, only one variable would be tested. There would have to be a placebo control group and, since subjects often improve on their own, an additional “spontaneous remission” group.

The results of the placebo control group and the spontaneous remission group are subtracted from the results of the test group in order to find out the actual scientific effect of the drug. Also, the test would have to be double-blinded, meaning that the subjects and the experimenters would not know who was receiving the test drug and who was receiving the placebo.

Amazingly, some scientists don’t always adhere to these rules. Some experiments are not blinded. Some peer reviewers don’t carefully read the studies they are supposed to read. Papers are published with “non-randomized” subjects and insignificant group sizes. Fortunately, over time, these poorly designed studies are exposed and discarded. So, while a single experiment does not usually produce significant advancement, repeat experimentation, over time, does produce the correct direction for continued scientific investigation.

This leads us to the next level of scientific reliability: “multiple lines of converging evidence” (MLCE). In addition to the scientific method and rigorous experimental design and implementation, when different branches of science all point to and support a common explanation of the natural world, a scientific theory, explaining a broad range of natural phenomena, is usually the result.

For example, the theory of evolution is supported by years of experimental findings from the fields of geology, genetics, biochemistry, molecular biology, bacteriology, virology and ecology. While there is no absolute proof in science, multiple lines of converging evidence point to the best explanation of cause and effect in the natural world.

“Science is a cooperative enterprise spanning the generations. It’s the passing of a torch from teacher to student to teacher … a community of minds reaching back to antiquity and forward to the stars.” — Neil deGrasse Tyson, Cosmos.

— Victor Dominocielo, a California-credentialed teacher for 36 years, is the human biology and health teacher at a local middle school. The opinions expressed are his own.

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