It ain’t what you don’t know that gets you into trouble.

It’s what you know for sure that just ain’t so.

That’s very true.

In a mild way, the quote also illustrates itself since it is so often attributed wrongly; perhaps most often to Mark Twain but also to other humorists — Will Rogers, Artemus Ward, Kin Hubbard — as well as to inventor Charles Kettering, pianist Eubie Blake, baseball player Yogi Berra, and more (“Bloopers: Quote didn’t really originate with Will Rogers”).

Such mis-attributions of insightful sayings are perhaps the rule rather than any exception; sociologist Robert Merton even wrote a whole book (On the Shoulders of Giants, Free Press 1965 & several later editions) about mis-attributions over many centuries of the modest acknowledgment that “If I have seen further it is by standing on the shoulders of giants”.

No great harm comes from mis-attributing words of wisdom. Great harm is being done nowadays, however, by accepting much widely believed and supposedly scientific medical knowledge; for example about hypertension, cholesterol, prescription drugs, and more (see works listed in What’s Wrong with Present-Day Medicine).

The trouble is that “science” was so spectacularly successful in elucidating so much about the natural world and contributing to so many useful technologies that it has come to be regarded as virtually infallible.

Historians and other specialist observers of scientific activity — philosophers, sociologists, political scientists, various others — of course know that science, no less than all other human activities, is inherently and unavoidably fallible.

Until the middle of the 20th century, science was pretty much an academic vocation not venturing very much outside the ivory towers. Consequently and fortunately, the innumerable things on which science went wrong in past decades and centuries did no significant damage to society as a whole; the errors mattered only within science and were corrected as time went by. Nowadays, however, science has come to pervade much of everyday life through its influences on industry, medicine, and official policies on much of what governments are concerned with: agriculture, public health, environmental matters, technologies of transport and of warfare, and so on. Official regulations deal with what is permitted to be in water and in the air and in innumerable man-made products; propellants in spray cans and refrigerants in cooling machinery have been banned, globally, because science (primarily chemists) persuaded the world that those substances were reaching the upper atmosphere and destroying the natural “layer” of ozone that absorbs some of the ultraviolet radiation from the sun, thereby protecting us from damage to eyes and skin. For the last three decades, science (primarily physicists) has convinced the world that human generation of carbon dioxide is warming the planet and causing irreversible climate change.

So when science goes wrong nowadays, that can do untold harm to national economies, and to whole populations of people if the matter has to do with health.

Yet science remains as fallible as it ever was, because it continues to be done by human beings. The popular illusion that science is objective and safeguarded from error by the scientific method is simply that, an illusion: the scientific method describes how science perhaps ought to be done, but how it is done depends on the human beings doing it, none of whom never make mistakes.

When I wrote that “science persuaded the world” or “convinced the world”, of course it was not science that did that, because science cannot speak for itself. Rather, the apparent “scientific consensus” at any given time is generally taken a priori as “what science says”. But it is rare that any scientific consensus represents what all pertinent experts think; and consensus is appealed to only when there is controversy, as Michael Crichton pointed out so cogently: “the claim of consensus has been the first refuge of scoundrels[,] … invoked only in situations where the science is not solid enough. Nobody says the consensus of scientists agrees that E=mc2. Nobody says the consensus is that the sun is 93 million miles away. It would never occur to anyone to speak that way”.

Yet the scientific consensus represents contemporary views incorporated in textbooks and disseminated by science writers and the mass media. Attempting to argue publicly against it on any particular topic encounters the pervasive acceptance of the scientific consensus as reliably trustworthy. What reason could there be to question “what science says”? There seems no incentive for anyone to undertake the formidable task of seeking out and evaluating the actual evidence for oneself.

Here is where real damage follows from what everyone knows that just happens not to be so. It is not so that a scientific consensus is the same as “what science says”, in other words what the available evidence is, let alone what it implies. On any number of issues, there are scientific experts who recognize flaws in the consensus and dissent from it. That dissent is not usually mentioned by the popular media, however; and if it should be mentioned then it is typically described as misguided, mistaken, “denialism”.

Examples are legion. Strong evidence and expert voices dissent from the scientific consensus on many matters that the popular media regard as settled: that the universe began with a Big Bang about 13 billion years ago; that anti-depressant drugs work specifically and selectively against depression; that human beings (the “Clovis” people) first settled the Americas about 13,000 years ago by crossing the Bering Strait; that the dinosaurs were brought to an end by the impact of a giant asteroid; that claims of nuclear fusion at ordinary temperatures (“cold fusion”) have been decisively disproved; that Alzheimer’s disease is caused by the build-up of plaques of amyloid protein; and more. Details are offered in my book, Dogmatism in Science and Medicine: How Dominant Theories Monopolize Research and Stifle the Search for Truth (McFarland, 2012). That book also documents the widespread informed dissent from the views that human-generated carbon dioxide is the prime cause of global warming and climate change, and that HIV is not the cause of AIDS (for which see the compendium of evidence and sources at The Case against HIV).

The popular knowledge that just isn’t so is, directly, that it is safe to accept as true for all practical purposes what the scientific consensus happens to be. That mistaken knowledge can be traced, however, to knowledge that isn’t so about the history of science, for that history is a very long story of the scientific consensus being wrong and later modified or replaced, quite often more than once.

Further posts will talk about why the real history of science is so little known.