When Common Sense Clashes with Science

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Robert Pavlis

What happens when common sense clashes with science?

A lot of gardening information is based on information provided by others. This mostly comes from past experience and common sense. But past experience is largely based on previous common sense. Great, great granddad thought double digging made sense, he tried it, it worked – whatever that means – and it has been passed down through the ages.

What happens when new science provides facts that disagrees with common sense? What do we do?

When Common Sense Clashes with Science
When Common Sense Clashes with Science

What is Common Sense?

We talk about it, we use the term, and we rely on it to get through life, but do we know what it is?

Webster defines it as, “sound and prudent judgment based on a simple perception of the situation or facts.” This sounds good, but if the conclusion reached is wrong, is it still sound judgement? If a conclusion is reached that ignores the facts is it still common sense?

Another definition is, “sound practical judgment that is independent of specialized knowledge or training.” So if you have had some training in gardening you can no longer have common sense about it?

Compost Science for Gardeners by Robert Pavlis

Wikipedia says, “sound practical judgment concerning everyday matters, or a basic ability to perceive, understand, and judge that is shared by (“common to”) nearly all people.” What this means is that you can’t exhibit superior or inferior common sense. It is only common sense if the majority agree.

I’d like to submit that common sense doesn’t really exist. Each of us possesses a level of ‘sense’ but certainly as adults, it’s not common among us. When evaluating a situation we all bring different knowledge, past experiences, and beliefs to the problem. To this we add the sense part, which is really an ability to solve problems. We take all of the current and past information, apply problem solving and reach a conclusion.

Once we have solved the problem, we turn around, look back at the process and say “that makes sense”.

Is Common Sense Really Common?

Do eggshells decompose in the garden?

Most gardening information says yes. So gardeners add them to compost bins and in no time at all, the shells seem to disappear. After all, if they didn’t, gardeners would end up with piles of shells in their fields.

The conclusion that eggshells decompose makes perfect sense, based on these facts.

As a chemist, I brought new facts to the table – at least to my table. I understood that calcium compounds are tough and don’t dissolve easily. Eggshells are similar to teeth and bones which don’t decompose any time soon.

By adding this additional fact, the common sense solution suggests eggshells don’t decompose. Instead they are fragile and probably break into smaller and smaller pieces until we can’t see them.

Since common sense depends very much on knowledge and beliefs, everyone will reach different common sense conclusions. Unless we all have the same facts, it is not very common.

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Not that long ago, common knowledge led everyone to conclude the Earth was flat and that the sun revolved around the Earth. There was agreement. Then science produced more facts and we went through a time where only some people believed, and eventually enough science was produced that convinced most people that the Earth is round and that we circle the Sun.

What I find hard to believe is that today 1 in 5 American adults still believe that the Sun revolves around the Earth. The numbers are the same in Germany and Great Britain.

Interestingly, young children believe the earth is flat and to them that is just common sense and it is difficult to get them to change their mind on this.  Over time they are exposed to more and more facts and slowly they begin to accept the idea of a round earth.

Science changes common sense.

Common Sense and Problem Solving

One of my all time favorite puzzles is the two piece pyramid. Two identical pieces that are put together to form a pyramid – what could be simpler.

photo source Creative Crafthouse

I first worked on this puzzle in my teens, at a friends house and I couldn’t solve it. Years later I bought my own and solved it in 30 seconds. Over the years I have watched many people struggle with it and have come to understand why it is so difficult to solve.

Most people do what I did at my first attempt. It is such a simple puzzle that it has to be easy, so we just use brute force and try each combination until we solve it. In my second try, I used logic and the solution was automatic.

Two different ways to solve the same problem. We all have different problem solving skills, but one thing is clear, humans are not good problem solvers. Most people don’t even try and just want answers, preferably simple ones. Few people are able to think out of the box.

Common sense depends very much on problem solving skills. If we are not good at solving problems, we should not expect to be able to reach common sense conclusions.

Common Sense and Priorities

Developing a common sense solution is really an exercise in problem solving, but each of us approaches problems differently. There is no accepted right way to do this, and most of us could not even describe the process we use. Our minds are able to bring together numerous facts, feelings, and beliefs and reach a conclusion – it just kind of happens.

A big part of this process requires us to prioritize each element. Is our belief more important than a scientific fact? If you strongly believe eggshells decompose and I show you evidence that they don’t – which of these takes priority? What if 10 scientists tell you they don’t decompose? Does that change the priority. At what point do the facts change your beliefs? This will be different for each of us.

Personal experiences or experiences from someone you trust, will be given a higher priority than experiences from a stranger, or scientific facts from an unknown expert.

Quantity matters and is one reason people believe so much nonsense on the internet. Once you have seen a so-called fact a hundred times you start believing it. How can it not be true when so many say it is?

You might be familiar with the National Enquirer, which publishes sensational garbage. Some people read the newspaper as a joke, but others accept the stories as being facts. Different folks set different priorities on their source of information.

There is no established way to prioritize this information. All of the information enters our brain, gets jumbled around and we end up with a common sense solution; at least one that is common sense to us. The lack of organised processing is one reason that the solution is rarely the true picture.

Take the case of creationism and evolution.

Before Darwin introduced his Origin of the Species, creationism was certainly the belief of the day. In fact Darwin was quite worried about introducing his theory because he knew it went against everything people believed. Anyone using common sense in those days agreed with creationism.

Fast forward 150 years and thousands of scientific reports that support evolution and still 30% of people in the US believe in creationism. The numbers are less in Europe, but still significant. This group puts a higher priority on their beliefs, allowing them to ignore the facts.

There is another complexity here. I have fairly good knowledge in biology, biochemistry and genetics, making it easy for me to understand natural selection. I am therefore more willing to accept the concept – it makes sense to me because of my specialized knowledge. The general public does not have this knowledge so they are more likely to reject the science because they don’t understand it, or they will accept it on blind faith.

When we don’t understand facts, we are less likely to give them a high priority, which is a real problem for science.

Science is Process Driven

Unlike our common sense process, science is a very structured process. Hypotheses are formed, experiments are designed to prove the hypothesis, results are gathered and analyzed and published for review. Others repeat the work and critique the process. In the long run, science is self-correcting and ends up with a set of accepted facts.

Common sense uses feelings while science uses measurements. Common sense relies heavily on single point observations while science uses controls to further ensure correctness. Even setting priorities is mostly a controlled process in science.

At times science may seem chaotic to general public, but it is highly structured to ensure correct data. The process of developing common sense opinions is anything but structured. This difference is significant and should make a big difference when we prioritize facts, but it rarely does.

Common Sense Meets Science

What happens when common sense meets science?

There are two possible scenarios. Either the two support each other and reach the same conclusion, or they don’t.

When you hear scientific facts that support your common sense conclusions, you embrace them. They are essentially a pat on the back for correctly solving a problem. The facts support your beliefs and make them even stronger.

However, when the science does not support your solution, you have to resolve the conflict in your mind. Do you accept the facts and change your solution, or do you give the facts a very low priority and let other factors control your common sense?

If you give a very low priority, your solution will not change. When Darwin first presented the idea of evolution, the general public rejected the idea because it was just too big a leap to change their belief system and they didn’t understand the science.

Climate change protest, photo credit; Jeanne Menjoulet
Climate change protest, photo credit; Jeanne Menjoulet

Dismissing facts is a very common response to new data.

As the mountain of facts grow, we each reach a point where we are forced to change our common sense opinion. That point is different for everyone because everyone has different knowledge, experience and problem solving skills.

Climate change is a good example. Twenty years ago few people accepted the concept. The facts flew in the face of everything we know about a stable earth – OK it is not that stable, but we think it is. But the data kept piling up. Study after study pointed in the same direction. In the past few years something important happened. The predicted severe weather started hitting the earth. This made things more real and it affected feelings. It became easier and easier for us to accept our role in climate change.

Just this week, a collection of 11,000 scientists from 153 countries, signed a declaration of climate emergency, but even that won’t convince everyone.

Pseudoscience is Not Science

In this discussion it is important to understand the difference between pseudoscience and real science. Unfortunately it is very easy to throw some numbers together and make any claim you want. These pseudofacts are gobbled up by people when they match their belief system.

Homeopathy is defined as taking a real working drug and diluting it over and over again until there is nothing left in each bottle. Proponents of this medicine even claim that the more you dilute the drug, the more effective it becomes.

This is complete nonsense no matter what kind of logic or science you use to analyze the idea and yet this is a six billion dollar industry which is growing rapidly. Testing by science has also found no basis for homeopathy.

The general public has a hard time differentiating between science and pseudoscience, which leads them to be more suspicious of real science.

The general public is poorly equipped to evaluate scientific facts.

Logical vs Emotional Arguments

Most hotly contested subjects have two clear sides. One side uses facts and figures to make their case. They prioritize science over feelings. The other side uses emotional arguments. They either don’t believe the facts or they prioritize feelings over facts.

Next time you see or hear a discussion about GMO, Roundup, abortion, religion, immigration or any other hot topic, put your own biases aside and just watch how the discussion unfolds. You will clearly see that one side is fact based and the other is emotion based. One side has prioritized science and facts, while the other side prioritizes beliefs and experience.

Common Sense Is Only a Tool

We need to use common sense in new situations or where we need to solve new problems which lack data. It is both useful and necessary. But it is a tool that should only be used in cases were we do not have good facts, which is quite common in gardening.

As the quality of facts increase we have to abandon common sense and start listening to the science.

Science has given us cars, homes, new food types, medicines, electronics, paper and the list goes on and on. Because common sense is neither common nor sensical, it has not given us very much except for a way to survive until more facts come along.

Next time you are having a discussion and someone tries to qualify their position by saying, “that’s just common sense”, you can tell them, “there is no such thing.”


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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

32 thoughts on “When Common Sense Clashes with Science”

  1. Climate change.
    Absolutely pollution is a problem but Western goverments have been increasing taxes for carbon and allowing unrestricted imports from China and India, countries with little to no pollution restrictions.
    Solar and wind are being touted as ‘green’ yet how many ppl have looked at the calculations. Number of wind turbines/ solar panels required to produce x energy, lifespan of product, the pollution from it’s construction, maintenance, demolition, and how much energy is produced from each.
    Then comparing it with coal turbines and/ or nuclear reactors, lifespan number needed, land required and energy produced.
    Ontario spent billions on wind turbines/ solar panels and associated hydro stations, and shut down coal plants. As it was explained to me, nuclear reactors can’t increase/decrease power production quickly. So Ont increased output of the nuclear reactors and now sell excess power to the US at a loss. The neighbouring US states use coal which can ramp up and down quicker as consumers require.
    IMO money would have been better spent with other initiatives. (Mass transit along the main highway) to reduce emissions, roads, less car owners, trucks. This would have been more beneficial to the environment.

    How many ppl believe climate change BC of commercials or from listening to an emotional radio/ Netflix special and how many have done the calculations?
    How many scientists will receive government funding for studies if there study goes against the consensus? If an oil and gas company fund a study would it be taken seriously?

  2. Whew…I like to try to read other reader’s comments first, in case what I have to say is redundant, but I gave up! :^D

    (As for the eggshells that vanish from compost heaps: I have observed that given the chance, chickens will devour eggshells… I can hypothesize that eggshells disappear because some critter is gobbling them up!)

    And as for the polls finding 40% of U.S. citizens believe the sun orbits the earth, I like to imagine that maybe some of those people misunderstood the question…which isn’t saying much, come to think of it.

    I’d never given “common sense” much thought. But it does look like people are finding their own sources of information, that culturally we are splitting apart and there isn’t a common ground from which “common sense” would grow. I wonder if in the future, post World War II will be seen as the peak of Western civilization, when we aspired toward education and equality…before fear, greed and superstition were allowed to flourish and pull us apart.

    Thank you for the engaging (if heart-breaking) topic!

  3. I found the editorial both enjoyable and edifying. Forty years in the high tech industry demonstrated to me the validity of your argument. I’ve heard the phrase”My gut tells me…” so often that I’ve considered selling antacids to executives. The discussion became interesting when I replied that “I’d had pizza for lunch and my gut told me…” Seriously, though, giving up a cherished belief (or a common sense solution) in the face of increasingly contradictory information is difficult. People seek reassurance of the common and shared experience, even it it is wrong. Catastrophic change – when it happens – can sometimes shift “common sense” beliefs – but people need to create new ones to substitute for the one’s they’ve lost. It was true in the high tech sector just as it’s true in gardening. We disguise it with data to prove a point, but we’re basically going out of our way to validate earlier assumptions so that we can avoid disruptive situations. For most people, disruptive technology poses a threat and challenge. And it doesn’t have to be “big disruptive technology”. But, it does have to be strong enough to cause people to question their “common sense” beliefs. I suppose most gardeners can understand this – after all, it was common sense that tomatoes, as part of the nightshade family, would be dangerous…

  4. Interesting article but not necessarily constructive and logical as more confusion and questions grow. Assumptions have been made and biasses exposed without adequate evidence, data or proof to back them.(not necessarily a bad thing, but it can be if the ‘truth’ is distorted and avoided.) The reality is that humans lack the knowledge and understanding of all the variables per se and even more how they interplay. In your criticism of those not having the ‘facts’ you lay bare your own bias of the ‘facts’ as you perceive them. Science should be neutral but it never is, humans interpret observations, measurements and data and even the concepts supposedly describing things as we endeavour to communicate our view of things within our own conceptual framework imprinted in our brains and neural networks. Science is useful as an empirical approach to test ideas and ratify the laws of nature or aspects of the physical world but it can never claim to know it all especially as it ignores aspects of reality like the moral and spiritual dimensions behind the physical. We would be better served if we acknowledge our starting points, our assumptions and premises, our worldview, our faith position, which in the main defy ‘proof’ but indicate our values and perspective and what we believe and let the data and whatever support these (or not) and let us see our way to improve the quality of our living in relationship to ourselves, our families, our communities, our nation, and even God. The case for finding out what God says and has revealed is perhaps the most pertinent question of all. Humans have many opinions and controversies keep intensifying and confusing us but we lack the knowledge, skills and wisdom to find the truth and real answers and bring peace. It’s high time to be honest and humble ourselves to the One who knows all, where it is all going and who holds the future. We have the choice, but will we choose to search out and connect and make that a priority or will we hold stubbornly to our ideas, beliefs and ways of living? That road is fraught with more problems and leads nowhere but more darkness and destruction. Look at the growing mountain of circumstantial evidence. Now that is more like common sense based on reality on evidence, on what is happening. Turn to God, change direction, let him give you the peace and joy we all strive for or should, and live!

    • Which god was that, please? The christian god (which sect, please), the Norse god(s)and goddesses, the primal earth goddess, Vishnu, Zoroaster, Hecate, Zeus or Jupiter, etc.? The all sort of conflict except for the assertion that “he/she/it” are the dominant all knowing, all seeing entity. I’ll take science and data that has at least some proof points over a faith based belief.

  5. So called common sense is often just “tribal epistemology”. This is the idea that when confronted with new information, you determine whether it is true or false by seeing if it agrees with ideas you and other members of your tribe already support. If it doesn’t agree with the common tribal knowledge then it must be false. Gardeners can be very tribal in protecting their dearly held beliefs, as you demonstrate repeatedly on your excellent blog.

  6. Can it be that common sense is merely the inductive precursor to deductive processes – generating the hypotheses that are then subjected to scientific testing? If my life experiences/observations teach me (sense making of the many external inputs that I receive) that the stars actually move across the sky at night, or that there are canals on Mars, or that the moon is covered deeply in dust, or that ulcers are caused by stress, then these things become “hypotheses” or guesses – until one day, we reach the moon, or send robot rovers to Mars, or scientists discover that in fact ulcers are caused by bacteria and these can be killed by antibiotics. (More serious progression of the disease requires other solutions.)
    We run into trouble when we are so invested in our existing sense making (our common sense) that we refuse to accept the new evidence that our guess is wrong. Surgeons operating on ulcers were one such group who initially poo-pooed the concept until the scientist offering the new hypothesis infected himself and then killed the infection with an antibiotic.
    Common sense is a natural occurring product of our efforts to make sense of the world. But we should be open to new evidence that challenges those “guesses”.
    The problem for those who discount global warming and the possibility of moderating it is that the test of their hypothesis that there is no problem – it’s just a cycle – will be a cataclysm for many in the world.
    Sometimes prudence is better than waiting for “proof”.

  7. My only disagreement is your statement about the earth revolving around the sun. It depends on your frame of reference. From the frame of reference of the earth, the sun does indead revolve around the earth. Generally, the sun is used as the frame of reference because then is it easier to visualize movement of planets within our solar system.

  8. “Not that long ago, common knowledge led everyone to conclude the Earth was flat and that it revolved around the Sun”

    Did you mean to write that the sun revolved around the earth?


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