Chapter 1. Why science matters

In our complicated world, our lives depend on many, many events and decisions outside of our immediate control as well as many within our control.  Science as a way of making rational, evidence-based decisions about the natural world offers the best method we have of ensuring those decisions achieve what we want.

Society’s responsibilities

Virtually everything we do to better ourselves has a downside.  Industries that make goods cause pollution, whether it be a copper smelter releasing toxic gasses or runoff from a corn field contaminating ground water with pesticides and fertilizer.  Consider the innumerable issues we face in our society:

·        food safety (bacterial contamination, chemical contamination)

·        efficacy of medical practices and drugs

·        effects of agricultural practices on the environment (pesticide use, fertilizer use, genetically modified organisms)

·        public and occupational exposure to background levels of toxins and other hazards in drinking water, air, and homes

·        environmental hazards of consumer products (freon, electromagnetic fields, lead in gasoline)

This list barely scratches the surface of the issues that affect us.  Moreover, many of these issues can only be controlled at the level of society:  as individuals, we cannot prevent farmers from using pesticides and fertilizer, other consumers from releasing freon, from buying leaded gasoline, etc.  We thus expect our government to act in our best interest on those issues that affect our population as a whole and to make decisions that allow or prevent use of practises and substances as they affect us. 

Of course, our government does make those decisions.  From an environmental perspective, we have banned or otherwise curtailed use of DDT, of (some types of) freon, of leaded gasoline, and of some second-hand exposures to tobacco smoke.  Yet we continue to use many other things that are potentially harmful:  carbon emissions are not taxed or regulated despite evidence of their contribution to global climate change, many other pesticides are still in use, and many aquifers and grasslands vital to the national interest are being exploited beyond their capacity to recharge.  Likewise, most attempts by industry to market new drugs are prevented by the government because the drug is deemed harmful. 

The scientific method is a procedure that is widely used throughout many dimensions of society (including government, industry, and academia) to make informed decisions.  Most importantly, it is an evidence-based means of making a decision.  An idealized view of the role of the scientific method in decisions of a societal level is:




evidence & scientific conclusions


social, political, legal, and ethical consequences of alternative decisions



Thus, science is (and should be) used to inform decisions, but there is no intent that it be the sole criterion.  For example, ethical considerations may override the science, as has been the case with stem cell research in the U.S.

History abounds with examples in which science was ignored in reaching policy.  A spectacular one was the Soviet suppression of genetics in the 1940s into the 1960s, leading to major agricultural failures.  Genetics was at odds with the communist ideology that everyone was equal (recall the book Animal Farm), and T. D. Lysenko was given the authority to suppress Soviet research on genetics, which included imprisonment and eventual death of several prominent geneticists.  (There is a UT connection here, in that Hermann Muller, who first showed that radiation caused heritable, genetic damage while he was at UT, moved from UT to the Soviet Union to show his support for communism.  The reality of the Soviet regime led him to escape and ultimately return to the U.S., where he resided when he won a Nobel Prize for his earlier UT work.)

In general, scientific considerations may be overruled (or even ignored) due to a variety of factors:

·        political ideology

·        financial interests

·        religion

·        legal precedents

·        various alternatives: superstition, instinct, hunches

Even when science is considered in making decisions, these factors can have a larger influence than they should.

Individual decisions

In our society, there is a striking disconnect between how we expect our government to behave regarding decisions (and how it does behave) relative to how individuals behave.  There are many issues that an individual faces for which the scientific evidence can be helpful: 

health:  diet (fast food), vaccination, cell phone use, tobacco use, alcohol use

cost-benefit analysis of expenditures

The magazine Consumer Reports is an evidence-based comparison of products for prospective consumers. 

For the most part, we all value cost effectiveness and welcome evidence on it.  We don’t all make the same choices given the same evidence, but our goals are often somewhat different – I might value quantity over quality in produce, in contrast to many others.  Yet when it comes to issues that may not affect us directly (at least financially or health-wise), we The Public often throw caution to the wind and abandon all evidence-based, scientific reasoning. There is an stunning, large fraction of U.S. citizens who say they believe in some aspect of the "paranormal" and other scientifically foundless ideas:


% claiming to believe it







Aliens have landed




Dinosaurs with humans


Communication with dead


had a pyschic experience





(based on a 1991 poll of 1,236 Americans; Gallup, G.H. Jr, and F. Newport. 1991. Skeptical inquirer 15:137-147). Likewise, even many of us in this class at least suspect there is some validity to several of these ideas (our first-day survey).

Belief in magic, aliens, and recent dinosaurs is undoubtedly harmless in most cases and can even be entertaining – people rarely carry such beliefs to extremes that might harm themselves, and believing in astrology can take some of the dullness out of life. There could be many social repercussions when a large fraction of a population does not know how to decide what is real -- wholesale criminal convictions of innocent people, failures to make medical and technical advances, failures to make other improvements in the standard of living, a decay in education systems, and much more. To a large extent, however, we do not expect the government to follow such beliefs. 


Yet there can be personal ramifications of not being able to know how to make an informed decision; most generally, you become a prisoner of what others want you to think and believe. Unfortunately, our educational system reinforces this trap, because it is heavily invested into teaching students what to think, rather than how to think.  This class should give you a method of making evidence-based, informed decisions.

How people make decisions about what to believe

The preceding table addresses beliefs in “weird” phenomena, but for many other things we wish to consider as well, we can find a wide variance in opinion (as you can observe from the class responses to the first-day survey).  To understand the reasons behind this difference in opinion, we start by considering the various factors that go into a person’s acceptance or disbelief of a phenomenon.  A few of the main factors are:


1)     the evidence – what you know about the issue

2)     compatibility with your world view

3)     reliability of the source

4)     consequences of accepting/doubting


Ultimately, all these factors are combined into a Decision Rule that each of us has, to arrive at a particular level of belief or disbelief.  When people disagree about something, we can attribute it to differences in (1)-(4), or their use of different decision rules.


What follows in this book

This book is not about past glories of dead scientists or the infatuations of living ones. It is instead about a method that empowers people and institutions achieve their specific goals. This method is widely known as the scientific method, though this term is a misnomer. Not only do scientists solve problems using this method, but it is also the mainstay of improvement in business and industry, and it provides a unique perspective on social institutions. Our goal in this class is to teach you how to use the scientific method and apply it to everyday health and social issues both for personal matters and to be informed about decisions made by our government. If your career is one in which you will be called on to solve problems, whether in business, law, or government, this style of thinking should be helpful in those areas as well.

However, because of this goal, the class emphasizes critical thinking rather than memorization of facts. In teaching you to tackle novel situations, we will teach you to analyze arguments and descriptions of new findings. For example, you will be given short news articles and asked to interpret the articles and to identify whether the research has certain features. So if your goal in taking a nonmajors biology class is to obtain an encyclopedic knowledge of biological facts, this class is not for you. But if you want to know how to identify weaknesses of a study or how to identify potential science frauds and cons, then this class should serve that purpose. Below, we list a few more examples of the ways that this class might help you as a nonscientist to think about everyday problems.



Being tested for illegal drugs

Do you know what testing practices best ensure your civil rights against erroneous test results?

A new study claiming that alcohol modest alcohol consumption improves longevity

Could you tell whether this study indicates that you should drink alcohol?

A 3-year study showing that 1 of every 200 University students carries HIV (the AIDS virus)

What does this number indicate about the chance that your partner is infected?

As a juror being asked to decide the guilt or innocence of a rape suspect based on DNA evidence

How might the prosecution and defense each present a biased appraisal of the evidence?


Copyright 1996-2000 Craig M. Pease & James J. Bull

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