Science is Never Settled

During some of our current political discussions we sometime hear that "the science is settled".  I have two main issues with this assertion.

1. This statement "the science is settled" indicates that science is not being used to support a meaningful and fact based discussion, but rather to squelch opposing opinions i.e. "because, shut up!".  Even if the correctness of the science is conceded, "the science is settled" statement is intended to overcome all other arguments.  In a political discussion these other considerations include legality/jurisdiction, budget/resources and competing interests.  All must be balanced in the political arena, and science is not a trump card.

2. In itself the statement "the science is settled" is a serious non-sequitur, because by definition science is never settled.  The fact that science is never settled and is always evolving doesn't take away from its power and utility - far from it.  I make my living in the technology space, which owes its existence to science.  My point is that science is sometimes represented as unchallengeable dogma, and this is wrong.

Science is About Questioning, Experiments and Proof

The basic pursuit of science is the acquisition of knowledge through hypothesis and testing.  If an idea or principle is not testable or not subject to question or disproof, it cannot be considered scientific.  Questioning the results of science is part of the process, not "denial."

Charles Sanders outlined four methods of settling opinion.  He ordered them from least successful to most successful (in his view).  From Wikipedia:

1. The method of tenacity (policy of sticking to initial belief) - which brings comforts and decisiveness but leads to trying to ignore contrary information and others' views as if truth were intrinsically private, not public. It goes against the social impulse and easily falters since one may well notice when another's opinion is as good as one's own initial opinion. Its successes can shine but tend to be transitory.
2. The method of authority - which overcomes disagreements but sometimes brutally. Its successes can be majestic and long-lived, but it cannot operate thoroughly enough to suppress doubts indefinitely, especially when people learn of other societies present and past.
3. The method of the a priori - which promotes conformity less brutally but fosters opinions as something like tastes, arising in conversation and comparisons of perspectives in terms of "what is agreeable to reason." Thereby it depends on fashion in paradigms and goes in circles over time. It is more intellectual and respectable but, like the first two methods, sustains accidental and capricious beliefs, destining some minds to doubt it.
4. The scientific method - the method wherein inquiry regards itself as fallible and purposely tests itself and criticizes, corrects, and improves itself.

Talking about "the science is settled" falls into category 2 - the method of authority.  The "appeal to authority" is a common logical fallacy during discussion of contentious issues.  If someone refers to authority or a consensus of authorities, then the argument is not scientific in nature.  I have found that those appealing to authority by using the phrase "the science is settled" are often trying to mislead the scientifically illiterate, or have been misled themselves.  When you say "the science is settled," I hear "''Shut up,' he explained."

Note that a key aspect of the scientific method is that inquiry regards itself as fallible.  Embracing the scientific method means embracing the likelihood of being disproven at some point, or at least being shown to have only an incomplete understanding.  It means that experimental data and methods are shared openly to allow recreation of results - or identification of flaws in the hypothesis or results.

Science Evolves

As a reminder of the ephemeral nature of scientific truth, here are some examples of once "settled science" being disproved or modified based on later hypotheses and testing.

• Aristotle formulated the idea of spontaneous generation to account for small life forms such as maggots and fleas.  This notion was "settled science" for over two millennia until disproved by the experiments of Louis Pasteur.
• Ptolemy's model of an Earth-centered universe was able to make pretty good predictions of planetary positions.  It was "settled science" for 1400 years until Copernicus and his heliocentric model.
• The Greek physician Galen created the model of unidirectional blood flow from the heart and liver to the rest of the body.  This was "settled science" until the Arabian physician Ibn al-Nafis described a circulatory model in 1242 and Marcello Malpighi discovered capillaries in 1661.
• Newton's laws of motion and gravitation were "settled science" from their publication in Principia Mathematica in 1687 until Albert Einstein formulated his general and special theories of relativity in the early 20th century.
• Einstein's theories of relativity capped what is now known as "classical" or pre-quantum mechanics.  Einstein's theories are remarkable for the accuracy of the predictions made from them. Even so, they were shown to have their own limits at the sub-atomic level.

Aristotle, Ptolemy, Galen, Newton and Einstein were all scientific giants.  They were also eventually shown to be limited or wrong in various degrees.  This is the fate of all scientists.

Despite imperfection, these men made great advances in our understanding of the world around us.  Each was less wrong than his predecessors.  Their models and theories provided increasingly useful predictions about the natural world.  This is why we pursue scientific exploration.  As I said above, science puts bread on my table.

Science is a Tool, not Dogma

The work of the giants above is science, not dogma.  This notion is a great advance over the period in history when the ideas of Aristotle, Ptolemy and Galen were considered dogma and were not subject to question.  For example, in 1632 Galileo was tried for heresy for defending the heliocentric model of Copernicus.  Hopefully the days of trying "deniers" like Galileo are past us.

I will note that there are those who use the changing nature of scientific results as an argument against science in toto.  This position is absurd.  While our understanding of the physical world may change tomorrow, it's still the best that we have.  Furthermore, the changes in scientific findings are not arbitrary, but instead are based on new theories, experiments and findings.

Even so, science is disprovable.  "The science is settled" is a posture, not a meaningful argument.  If the science of the giants wasn't settled in the past, what makes you think that ours is today?