Skeptoid PodcastSkeptoid on Facebook   Skeptoid on Twitter   Skeptoid on Stitcher   iTunes   Google Play

Members Portal



Get a Free Book



The Heisenberg Principle of Scientific Knowledge

by Stephen Propatier

September 18, 2014

Share Tweet Reddit

Donate The Heisenberg uncertainty principle is one of the more misunderstood concepts in particle physics. The uncertainty principle says that we cannot measure the position (x) and the momentum (p) of a particle with absolute precision. The more accurately we know one of these values, the less accurately we know the other. The inaccuracy is not a function of the measurement, rather just an inherent property of wave mechanics at the quantum level. This is counter-intuitive to how we perceive the Universe. Practically, this uncertainty only exists on the atomic scale.

Scientific certainty is in one way, a lot like the Heisenberg uncertainty principle. No matter how precisely science measures we will never achieve 100% certainty. Most people think of scientific knowledge and associate it with absolute certainty. Science is commonly presumed to be the final answer. Actually, science is a method to systematically answer questions using careful logic and precision. Most people's superficial understanding is that science delivers answers with unequivocal certitude. Factually, this is just plain wrong. The scientific method is by far the only reliable method to understand the natural world, just never with 100% certainty. The media will often present every little bit of new scientific evidence as if it is 100% accurate and infallible. We see examples of this error every time the evening news promotes new research. Presenting the research as an unassailable new truth about the subject. Reports presented this way can lead people to assume that research is a fact to a 100% certainty. Assuming that facts can only have 100% accuracy is a logical fallacy. That instinctual assumption that fact equals 100% certitude, makes the discovery of scientific uncertainty so troubling for people.

There will always be a tiny bit of uncertainty about any scientific knowledge. Scientific evidence can show that we are very, very certain about something, 99.99999% certain, just not 100%. It sounds bad to us humans, and what we draw from that discovery is that science doesn't have the answers after all. We assume that any uncertainty, no matter how small, means that it is in error or worse that any competing claims are equally valid. That tiny uncertainty is misunderstood, like the case of the Heisenberg uncertainty principle. Uncertainty is good, not bad. For you see, if it was possible to determine the actual position and speed of that particle, everything we take for granted wouldn't work: nuclear power, radio, your smartphone... everything. They wouldn't work like they obviously do. Scientific understanding is just like Heisenberg's principle: 100% certainty is impossible in science.

We expect answers from science, and we get them. It is a relative term. There is always a little wiggle room. It is that wiggle room that makes science hard to explain and easy to attack. When people don't like the answers that science provides, they commonly attack the science. If you can't challenge the evidence you attack gaps in the knowledge. When some gaps are closed there are always tiny ones left. Instead of looking at the increasing level of certainty, they will attack the next uncertainty, so on and so on. This is not a true objection to the evidence. It is a attack that plays into human failings, playing into the false impression that only 100% certainty is worth acknowledging.

Truth in science is probabilistic, like all knowledge. The only certainties in knowledge are things that cannot be falsified like religious belief. Creationists are used to religious absolutes so it is no surprise that they demand it from science.

But creationists aren't the only ones. It is a common pseudoscience tactic to minimize the evidence and maximize the uncertainty. In our information age we are all manipulated by the uncertainty surrounding science. It makes us vulnerable to the defenders of woo. Everything from homeopathy to arguments against the science of climate change focus on the uncertainties, the "maybes" of the the evidence.

Here are some common examples:

Homeopathy—Dana Ullman, writing for Huffington Post, asserts that "[The 'evidence' against homeopathy] is a very controversial and some say extremely flawed review of homeopathic research. This review sought to compare 110 placebo-controlled homeopathic studies and with a 'matched' group of 110 studies testing conventional medications. The researchers appropriately sought to evaluate only those studies that their criteria deemed of sufficiently 'high quality.'" Rather than challenging the findings, Ullman alleges that the researchers picked high-quality studies because they were biased against homeopathy, without noting that he himself has selected poor-quality studies biased in favor of the practice.

Anti-GMO—The Institute for Responsible Technology claims that, "By mixing genes from totally unrelated species, genetic engineering unleashes a host of unpredictable side effects. Moreover, irrespective of the type of genes that are inserted, the very process of creating a GM plant can result in massive collateral damage that produces new toxins, allergens, carcinogens, and nutritional deficiencies." Although this might be a reasonable potential future concern for genetic modification technologies generally, thus far the careful, monitored, and controlled products of that technology have not resulted in a single case of any such circumstance and are unlikely to given the present conditions. IRT therefore cite no specific threats and instead use fear-mongering hypotheticals.

Acupuncture—The novelist Chris Titus, writing at, claims, "Similar to the many styles of martial arts that exist, there are also many styles of acupuncture. When you consider the diversity of styles, it doesn't seem appropriate to perform clinical trials on one style and make generalizations about an entire medical practice. Studies should first seek out the most effective styles for each condition. Then these styles should be tested against 'sham' acupuncture as well as current mainstream therapies. Otherwise, there will never be accurate data with which to stem the growing rift between Eastern and Western medicine." However, Titus provides no description of which purported styles are effective, claims tests are inconclusive and are not useful, and (like Dana Ullman does for homeopathy) Titus asserts that the popularity of the treatment is a better indication of its efficacy than scientific studies.

Anthropocentric Global Warming—John Hawkins's opinion piece at states, "Questions are not decided by 'consensus.' In fact, many scientific theories that were once widely believed to be true were made irrelevant by new evidence. Just to name one of many, many examples, in the early seventies, scientists believed global cooling was occurring. However, once the planet started to warm up, they changed their minds. Yet, the primary 'scientific' argument for global warming is that there is a 'scientific consensus' that it's occurring. Setting aside the fact that's not a scientific argument, even if that ever was true (and it really wasn't), it's certainly not true anymore. Over 31,000 scientists have signed on to a petition saying humans aren't causing global warming. More than 1000 scientists signed on to another report saying there is no global warming at all. There are tens of thousands of well-educated, mainstream scientists who do not agree that global warming is occurring at all and people who share their opinion are taking a position grounded in science." Besides the fact that those lists are meaningless and small—using any person with a Bachelor's degree or greater in any science from any institution (e.g. a doctor of biology from an Evangelical bible college affirming his ideological disagreement with climatology)—scientific consensus is not evidence of global warming. Instead, the relationship is the reverse: there's consensus because there's a great amount of scientific data leading to the conclusion that global warming is a real and serious threat. Hawkins's argument is not based on evidence, but on argumentum ad populum, and a weak one at that.

All of these quotes have a similar mode of attack: science is uncertain or incomplete therefore the answers are useless. The argument is a mind trap to produce doubt and minimize the mountains of evidence refuting these claims.

We are predisposed to like certainty it is an inherent human trait. Dr. David Rock, writing in Psychology Today, notes that:
A sense of uncertainty about the future generates a strong threat or 'alert' response in your limbic system. Your brain detects something is wrong, and your ability to focus on other issues diminishes. Your brain doesn't like uncertainty—it's like a type of pain, something to be avoided. Certainty on the other hand feels rewarding, and we tend to steer toward it, even when it might be better for us to remain uncertain.
Offering certainty is reassuring and it's convincing. Demanding certainty is equally reassuring. It plays into our cultural norms as well as our default sensibilities. When we are educated we're given facts. We are required to know the answers. The answers are right or wrong, black or white. Even after education, we surrender to authoritative structures, laws, rules, and bureaucracy. Absolute answers are considered superior to uncertain ones. Science, since it confesses itself to have a possibility of error, must belong in the second class. That conclusion is wrong but there is no denying that it works as a tactic to distract from the facts.

You will only see 100% certainty in situations where science has no sway. The beauty of science comes from its ability to change our minds and admit error. If you've never admitted you're wrong, it doesn't mean you've made fewer mistakes. Anyone can say they're absolutely certain. It's a bit harder to never, ever make any mistakes. Scientists understand the difference, so they don't say they're absolutely certain. Not because the answer is weak, rather it is because they've just got higher standards for certainty. Even if every available scrap of evidence can be in support of a single hypothesis, scientists still won't say they're absolutely sure. A tiny amount of uncertainty is demonstrates strength not weakness. Additionally presuming that a small amount of uncertainty means that another idea has equal merit is also completely false A tiny uncertainty doesn't mean that any given theory is equivalent to all other possible explanations. There are degrees of confidence. Some theories have more certainty/evidence than others. Demanding 100% certitude is an illusion used by people who have low standards for evidence.

Demanding certainty is a logical fallacy, called the false dilemma fallacy, which is an argument that claims you can only decide the truth of something that is colloquially black or white, and that grey is unintelligible and therefore useless. The rhetorical fallacy asserts that people are incapable of determining the difference between an almost white shade of grey and an almost black shade of grey. This is simply untrue. Good science is a hairbreadth away from being either black or white, but is never truly, unequivocally black or white for all time. That does not mean it is impossible to know if something is very very certain.

Authoritative answers are easy, comforting, and reassuring. They make us feel good, but the sense of security they provide is false. Certainty is the hallmark of the believer or the scam artist. It is only ideology or deception that produces absolute knowledge.

Science gives us real answers about ourselves and the Universe. Faith didn't get us to the moon. Homeopathy didn't cure smallpox. The creation myth didn't give us gene therapy. Science is messy, complicated and uncertain. But it is the absolute best method to learn what is really happening. Demanding certainty from science is demanding faith not knowledge, illusion not fact.

Uncertainty is not bad. When someone tells you that there is uncertainty about any scientific knowledge that is when you know you are dealing with a scientist not an ideologue.

To quote Isaac Asimov, in his essay "The Relativity of Wrong":
When people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together.

by Stephen Propatier

Share Tweet Reddit

@Skeptoid Media, a 501(c)(3) nonprofit