Scientifically Speaking

One of the big challenges faced by scientists is communicating their findings to the public.  Very often, it is the case that they report one thing, but the public hears something completely different.  Scientific language often gets interpreted differently by people who only speak Common English and not Scientific English.

For example, let's take one of the tactics used by Creationists, those people who refuse to believe the fact of Evolution because it contradicts their religious beliefs.  Creationists like to make a point that evolution is "only a theory".  In common usage, a theory is just a guess that someone makes.  We say things like, "I have a theory that the dog ate my sandwich".  It's a guess we make, and we're going to go out and look for evidence of it.  In Scientific Language, a theory is the current best explanation that we have for something that we observe in the universe.   A theory of gravity explains how we think that gravity works.  We all know that gravity exists.  We don't say, "I have a theory that gravity exists".   No, it's an observed fact.  However, scientists have a theory of how gravity works that explains gravity and takes into account relativity and quantum physics.   In Scientific Language, the word we use for a guess is a hypothesis.  A scientist would say, "My hypothesis for the disappearance of my mid-day sustenance is that the canine inhabitant of this domicile has consumed it".

When we talk about the Theory of Evolution, we're talking about our explanation for how evolution has occurred and what mechanisms drive it.  We're not making a guess that evolution could be true.  Evolution is an observed fact of nature.  There is no doubt about it.  However, there is still scientific debate over some details of the explanation.  Such debate is healthy because it is how we learn more.  It doesn't indicate that there is doubt about whether evolution is true or not.

Another example where I see this language disconnect is when talking about the results of some study or experiment.  For example, suppose a study was performed that was aimed at determining if acupuncture was effective for reducing pain.  The scientists would report, "the study showed no evidence that acupuncture was effective at treating pain".   The problem here is that to say "the study showed no evidence" leaves room for the reader to think that there could be evidence, but it just wasn't found by this study.  It's like saying, "there is no evidence that there was a second shooter who really killed President John F. Kennedy".  People who want to believe in a second shooter can easily believe that the investigators simply didn't look in the right place to find the evidence of the second shooter.

Here's where the real problem is.  In fact, scientists know that no study is final proof of something.  There is always more to know.  In addition, experimental studies are carefully designed to test specific hypotheses.  There are very strict conditions specified that are used to determine if the hypothesis is correct or not.  So a given study is only looking at one part of a problem.  There could be other evidence that this study wasn't looking for, and thus wouldn't find.  Every theory is tentative - it could change if more evidence is discovered.  That's the strength of science.

On the other hand, the fact that an experiment was conducted and had negative results is itself evidence.  If we test acupuncture and find that there is no difference in pain whether acupuncture was used or not, then we have evidence that acupuncture did not improve the pain.  We shouldn't say "there is no evidence that acupuncture improved the pain".   We should say, "the evidence of this study shows that acupuncture does not improve pain".

In some cases, many experiments have been done with no positive results. At that point, scientists should be clear and simply say, "given all the evidence that has been gathered, we conclude that acupuncture does not work".   Simply adding the statement about having gathered data gives more weight to the conclusion.   As scientists, we have to be true to our value of being accurate in what we say.  However, if we are going to communicate our findings in a way that people can understand and use to make better decisions in their lives, then we have to speak in a way that is understood by people who don't speak Scientific English.

There's a new study that indicates....

I recently watched a documentary called "Forks over Knives".  The premise of this film is that you can avoid a lot of illnesses, especially cancers and heart disease, if you avoid all animal-based foods and eat only non-processed, plant-based foods.  Let me state right from the start that I immediately saw this for what it is - vegan propaganda.   I found some good blog posts that dissect the film bit-by-bit and point out what is wrong with the arguments and with the science.  That's not the point of this post.

What I want to write about today is one particular bit of evidence that the film uses to make its case.  They refer to a study done in India that studied the effects of a diet high in casein (milk protein) on the incidence of cancer in rats.  They report that rats who received a high-casein diet had higher incidence of cancer than rats on a low-casein diet.  From this, the film draws the conclusion that diets high in animal proteins promote cancer growth, and thus all animal products should be avoided.

If you take this as reported, it's pretty scary.  In fact, even if you don't accept the leap from casein to all animal proteins, it makes you think you might want to cut down or eliminate dairy foods from your diet.  But, I'm skeptical.  If this link between milk and cancer had been proven, first, we would see rampant cancer in places like the U.S. where dairy consumption is high.  We don't see this.  Second, many more studies would have been performed to verify this claim, and it would be all over the news.  It's not.  So what's the truth?

First, we have to look at what the study really said and what it was trying to find out.  Any scientific experiment is designed to answer a question.   Scientific experiments are expensive.  They are carefully controlled to limit the number of different factors that could influence the outcome.   They want to get quality answers to a specific question with the least cost in time and resources.  So what was the casein experiment trying to accomplish?  They were specifically looking at a carcinogen called aflatoxin and the effect of the level of protein in the diet on aflatoxin's ability to cause liver cancer.  Why aflatoxin?  Well, aflatoxin is produced by a fungus that can grow on grains in humid climates.  I assume that in India, there is a higher risk of being exposed to aflatoxin due to their diet that is high in grains and the tropical weather.  Thus, it makes sense that Indians would be studying this toxin.  Why study using casein?   I don't really know.  I'll guess that it's because it's a readily available protein that's available in a pure form that can be used to carefully regulate the protein level in an animal's diet.   It's probably just the typical diet protein that biologists use.

So, now that we know what the Indians were studying, let's look at the results.  What the movie didn't say was that over half of the low-protein rats actually died before they reached one-year old and were examined for cancer.   Low-protein actually means malnourished.  The underfed rats didn't have enough protein in their diet for their livers to grow and properly metabolize the aflatoxin.   So the alfatoxin destroyed their livers and killed them.  The high-protein rats were actually receiving a balanced diet.  Their livers grew properly and were able to metabolize the aflatoxin.  However, the aflatoxin doses were very high, so they still got cancer, but at least they lived long enough to get a cancer.

This result also gives us insight into what else the Indians may have been trying to study.  In a country with rampant malnutrition, they may have been wanting to see if Indian children without sufficient nutrition were more susceptible to aflatoxin damage.

So, let me summarize all this.  In India in 1968, researchers performed a series of experiments on rats to see if malnutrition would make it more likely for children to die from exposure to a toxin that is often found in their food supply.   The researchers happened to use casein, a readily available protein to carefully control the nutrition level the rats received.   Thirty or so years later, a doctor with a strong ideological bias that animal foods are bad for you, took this study and misrepresented the results to say that the experiment showed that high levels of animal-based proteins cause cancer growth.

There are two obvious, but unfortunately common, problems with this.  First, the doctor took a study intended to measure one thing and reported only specific aspects of it to make his case, which had little to do with the original study.  Second, an experimental study on rats was generalized and reported as if the results were automatically and obviously applicable to humans.  Rats aren't people (even if some people are rats).  However, mice and rats have enough in common with people biologically and genetically that doing initial studies on rodents can provide information that is useful for later studies with humans.

Vegan propaganda aside, we see this kind of situation all the time.  We see headlines like "Eating walnuts cuts breast cancer risk in half".   If you look closer at the study, you find that it was a mouse study where half the fat in the mice's diet was replaced by walnuts.   Breast cancer incidence was reduced.  I don't know the rest of the details of the study, but I can guarantee you that it doesn't show conclusively that you can cut your breast cancer risk in half by eating some walnuts every day.

The media sensationalizes scientific results to make a story.  The result is that people don't believe anything that scientists say.  "Walnuts prevent cancer?  Heck, last week they said that they were bad for you."   Never assume that a headline accurately represents the results of a scientific study.  It's more likely that the science has made some advancement on one piece of the puzzle that is cancer (or some other disease).   The true story is likely much more interesting than the glossy, sensationalized version that the media will give you.   The link between malnutrition and the risk of aflatoxin poisoning is much more interesting, useful, and true than "animal-based foods cause cancer".

Evidently True

I grew up in a Catholic household in a predominantly Christian part of the rural Midwest.  It seems like there's a church on every street corner of my hometown.  The Christian world view was part of our culture and our identity.  As a young boy interested in science, it's therefore no surprise that one of the sources of information that I was given was a cassette tape that talked about all the evidence of God's work in nature.  I listened to this cassette repeatedly. 

It's been many years, so I only really remember one particular part.  The preacher (I assume he was a Christian preacher or minister that made the tape) was talking about the fact that when you look at the branch of a tree, you'll notice that the side branches do not grow out of that branch in a random pattern.  In fact, they follow a repeating pattern where, for example, every fifth branch is pointing in the same direction.  This order was evidence of God's hand in the creation of a tree.   God made the tree with a certain logic, and this was evidence of the creator's work. 

For a Christian, or any believer, the existence of a god is assumed.  It's part of the fabric of the Universe.  As such, any observation of order in the Universe is considered evidence of that god's existence.    The problem with this argument is that it is circular.  There is an assumption that a god exists with certain properties and any observations that are made are taken as evidence that the god exists.   The argument is "God exists.  God creates order in the world.  I see order in the world.  Therefore, God exists."   The argument implies that the only way there can be order in the world is because God causes it.  Thus, any order is evidence of God.  It's not a valid argument to assume something is true and then use that assumption to argue that it is true. 

Another problem with this is that the selection of evidence is arbitrary.  Observations that demonstrate their claim is taken as evidence; any observation that contradicts it is ignored.    If something is true, then there shouldn't be contradictory evidence.  If there is, then the thing can't be true.  In reality, if there is contradictory evidence, perhaps you don't have to throw out the idea altogether, but you need to revise it to account for the contradictions.

Let me give an example of something that is also a part of the fabric of the Universe - gravity.  Gravity is a basic property of matter.  Anything with mass will attract anything else with mass.  On the earth, we see this in the fact that things fall to the ground.  The gravity of the earth is so large that we don't normally notice that all the smaller things are attracting one-another, but this fact has been verified in laboratories and in outer space.  There are other known forces that cause objects to be attracted to one-another, including the strong nuclear force, the weak nuclear force, and the electromagnetic force.  When we remove the effects of those other forces, we still find that gravitational force is there.  Similarly, if we see two objects being attracted to one-another, we don't assume it is because of gravity.  We look at all the possible explanations and then decide if it is because of gravity.

We didn't start out with some theory of gravity from the start and afterwards looked to find evidence of it.  On the contrary, we observed that things fell to earth, and we wondered why.  As we studied this more and more, scientists like Sir Isaac Newton and others did experiments to measure the effects of gravity and to come up with a description of how it works.  Over the centuries, our understanding of gravity has grown, and it helps us to understand how the Universe works.  Everywhere we look, we find that the effects of gravity are there.  There are no contradictory observations.  The interesting thing is that we still don't know exactly what causes gravity.   I think scientists are still working on trying to explain how gravity is related to Relativity, as Einstein described it, or with quantum mechanics.  

The argument about gravity is like this: "We observed that objects attract one another.  The force that we call 'gravity' explains that attraction.  Therefore, gravity exists."  This is not a circular argument.  We don't assume that gravity exists at the start.  The existence of gravity is the conclusion.

If we wanted to follow the same process for proving the existence of a god, we would start with our observations.  What are these observations?  We see order in nature.   Is the existence of a god the best explanation for this order?  Scientists have observed true randomness on the quantum scale.  How does an orderly creation explain this?  We see "good" things happen.  Is the existence of a god the best explanation of this?  We see "bad" things happen.  How does the existence of a god explain this apparent contradiction?  

The more we know about nature, the more we find that there are better, simpler explanations for the apparent order in the universe than "god did it'.  For the example of the regularity of the branches in a tree, we know that natural selection would have favored trees that can position their leaves in locations that capture the most sunlight.  A tree that grows branches in regular intervals, thus filling every available gap, would collect more sunlight than one that grew branches at random.  Random branches would likely leave gaps (missing the opportunity to capture sunlight), and there would be branches that block other branches (wasting energy spent on growing the branches that are blocked).   Over the millions of years that trees have been evolving, the individual trees of a given species that did the best at collecting sunlight would be more successful.  They would have more energy from the sun that they could use to produce more seeds.  Over the generations, their offspring would be more successful than the offspring of trees with worse branch placement.  These "orderly branch" genes would come to be dominant in the population of trees.  Eventually, all the trees in the population would have these orderly branches.  Thus, it's no surprise that all trees of a species show the same order to their branches.  They are all descendents of trees that developed a particular genetic mutation that allowed them to have more orderly branches than the trees before them. 

The existence of orderly branches in a tree is evidence of evolution.   Like gravity, evolution is a universal property that we have observe everywhere we look.  It is completely consistent with all the observations we make, and it accurately predicts what observations we will make in the future.  We continue to learn more and more about evolution as we gather evidence.  When we find evidence that appears to contradict evolution, we generally find that the evidence actually clarifies our theory of evolution.   If we ever found evidence that truly contradicted evolution, we would be willing to throw away that theory in favor of one that explains all the evidence.  This is how we learn about the world.  This is how we increase our knowledge of the Universe and better understand our place in it.  This is how we use evidence.