Teaching Critical Thinking in Science Education

As we begin to teach about science we naturally find a distinction arises between doing science and thinking about science.  In a science class the emphasis may be on teaching the students how to do science.  This is to teach them about the scientific method and its application in many different settings and fields.  There is a fear that spending too much time on thinking about science produces graduates who do not know how to actually do science.

Thinking about science can take a few different forms.  It can mean a history of science and scientists.  This kind of study will focus on developments in the scientific method and those who made advances in its utilization.  It can be a history of outcomes as the advances of science are used to help society.  While the scientist may appreciate this focused attention on the field it is nevertheless still understood to be a kind of history and not science itself.

Thinking about science can also take the form of speculation about where science can go and the abstract principles that make science possible.  Sometimes such studies are ahead of their times and they, in a way, predict not yet realized advances in science.  And yet the scientist might feel that this would have been achieved anyway and that the speculative side is what the modern scientific revolution was trying to avoid.  The “philosophy of science” can sound like it might return the field to Aristotle after so much work was done to free it from that framework.

In the following, I want to do some history of science, and some of what might be considered philosophy of science as just outlined, but my larger goal is to consider how we can teach our science students to be critical thinkers.  I understand this to be the central part of the scientific method.  Thus, although I am a philosopher, I believe that by teaching our science students to be critical thinkers we are teaching them to be scientists. We are teaching them to do science.

I have four steps in this process.  The first is to consider what it means to think critically.  This is a platitude in education and as such it can be well intended but emptied of meaning.  What does it look like to give critical thinking its full meaning?  Second, I want to consider what science studies.  This will require that we do critical thinking as we examine the subject of science.  Third, I want to apply critical thinking to the idea that there is a conflict between science and religion about origins.  I will be so audacious as to assert that we can relieve that tension by critical thinking.  And fourth, I will spend some time on an application of that tension, namely, dating methods.  This is the goal of the prior three.  It is an area where we make claims that go unnoticed (“hey, look at that rock, it is millions of years old”) and yet these same claims are burdened with philosophical assumptions that make them ripe for critical thinking.

Step one.  What does it mean to think critically?  I have more often than not encountered the attitude that it means “to be negative.” To be critical means, in that context, to give negative feedback about a book or performance.  As a secular university professor, I have also encountered those who say that teaching students to be critical thinkers means to teach them to reject their faith.  They come to university with a faith of some sort and the wise university professor teaches them how to reject this faith.  These two senses of the phrase are linked then because the student is being taught to be negative about their prior faith commitments.

Neither of those are getting us to think critically.  What I mean by it here, and what I think we want to teach our students, is careful consideration and judgment especially about assumptions and with the goal of understanding meaning.  So, the student needs to be taught now to 1. Form judgments, 2. Identify assumptions, 3. Analyze them for meaning.

Notice there is nothing in this definition that is inherently contrary to faith.  There is nothing in this definition that inclines toward, or requires, philosophical materialism.  Indeed, critical thinking can equally be applied to faith commitments and philosophical materialism.  It is the use of reason to try and understand.  And to understand requires first that we can grasp the meaning of a belief.  So, there is an intimate connection between critical thinking and meaning.  The critical thinker examines assumptions for meaning and exposes meaninglessness where it is present.  If we remember our history of philosophy, we will remember that the materialists did not fare well under the critical examination of Plato.  The university professor who looks forward to teaching students to critically examine their faith will also have that lens turned on their own beliefs.

Critical thinking is a central part of the scientific method and therefore a central skill to be taught to science students.  Broadly speaking, the scientific method requires positing a hypothesis and then considering ways to test this hypothesis to find if it is falsifiable.  This is simply the application of logic and a science student who does not know logic will not get along very well.  The scientific method relies on what is called modus tollens: If P then Q, not Q, therefore not P.  If this hypothesis then this outcome, but we can falsify this outcome, therefore not this hypothesis (it is false).

The student must be able to form a hypothesis and then construct this type of logical test.  As such, the student must learn how to identify the assumptions in the hypothesis.  The hypothesis is only true if its assumptions are true.  A hypothesis with false assumptions is also false.  It shouldn’t be hard to see that this is an essential skill for science students.

But how do we teach students how to identify assumptions?  One of the fastest ways is to remind them to do what they have already been doing since they first learned how to talk.  When we are told something, say, the earth is 6 billion years old, the child naturally asks “how do you know?”  This requires a backing up to explain the assumptions, or premises, that led to this conclusion.  Simply ask: “how do you know?”  And we can ask this all the way back to first assumptions, first principles, or most basic presuppositions.  A critical thinker is ready to do this when they are presented with a theory and also ready to do this to their own beliefs.

Step two.  What does science study?  Well in the medieval sense the answer is “everything.”  There can be the theological sciences and the natural sciences.  It simply means “knowledge.”  But that isn’t what we think it means today.  Science is the study of the laws of the natural world.  We easily recognize the phrase “laws of science.”  And science is focused on the natural world as opposed to what theology or metaphysics might study.  What laws govern the world?

These laws are discoverable because of the laws of thought.  I pointed out earlier the role of logic in the scientific method.  Logic is the science of inference.  It is the study of the laws that govern inferences.  Insofar as the scientific method requires inferences (and it does) it requires that the student knows logic.  But logic itself is the application of the laws of thought (reason).  These laws are more basic than logic or the scientific method because they are assumed by both.

The laws of thought (reason) are identity (a is a), excluded middle (either a or non-a), and non-contradiction (not both a and non-a).  You can see that if these laws are not the case then no science can be done.  Image if a law is not a law.  Or something could be both a law and not a law at the same time.  These are laws of thought but also laws of being.  There are no square-circles or uncaused events.

Now, how does this fit into our second step here?  Science is using the laws of thought to construct experiments (requiring the laws of logic) to understand the laws of nature.  Science is not merely empirical (only using sense data).  The senses, and what can be sensed, are only a part of the scientific method.  It is true that science studies what can be sensed and if something cannot be sensed it does not fall under the purview of science (as we use that term today) although this does not mean it cannot be studied (think of theology and metaphysics).

As the study of the laws of nature, science is not the study of the origin of the laws of nature.  Consider how vastly different these two subjects are.  The laws of nature now exist and can be studied but this does not mean they have always existed or have always been as they are now.  The scientific method would have no way to study such claims.  The scientific method currently applied in a laboratory cannot be applied to the past.  It occurs in the present.  And it has only occurred in human history for a very short period of time.

The laws of nature cannot explain their own origins.  To claim such would require that they exist to then bring themselves into existence.  They would both have to exist and also not exist at the same time.  This is a violation of the law of non-contradiction.  However laws came about, it must be by something else and not the laws themselves.  This means that even the best scientific theory about the laws of nature cannot tell us about the origin of these laws without overextending itself and becoming unsound.

Step three.  You should be able to see how this brings us to the precipice of the conflict between science and religion.  This conflict is almost exclusively fought out over the question of origins. Adherents on the science side and on the religion side can agree on the force on gravity.  But they do not agree about the origin of gravity.  The scientist might claim the side of logic and reason while putting the theologian on the side of superstition and pre-modern ignorance.  The theological might claim the side of the need for more than the material life and put the scientist on the side of naturalistic reductionism that empties existence of meaning.  Either way, little to no progress has been made in this struggle.

I propose we use the skill of critical thinking to resolve this conflict.  What field best is best equipped to answer questions about origins?  It would be the field that teaches critical thinking.  Both science and religion come to the conflict with assumptions.  Science assumes naturalism and religion assumes revelation.  It is philosophy that teaches critical thinking about both.

The conflict has been ongoing because of a hidden assumption.  That assumption was that we are limited to one of these two options.  As soon as we see this as the false dichotomy it is, then we are freed to consider philosophy as a contender.  It will not be surprising if both science and religion set aside their grievances to now take aim at philosophy.  They can point to a dismal track record for the philosopher.  And in one way they would be correct.  Many things have passed under the name “philosophy.”  However, we are defining it here especially in its critical thinking function.  This is the role exemplified by Socrates.  And Socrates made progress.  It was a kind of negative progress.  That is, he exposed those who think they know but do not know.  And that is what philosophy will do here also.

Step four.  A critical examination of an example will help explain step three in more detail and really bring us into understanding the role of critical thinking for college students.  And that example is dating methods.  This is a fun example because of the obvious confusion about its reference.  What student isn’t interested in dating methods?

The contemporary scientist will comfortably say the universe is over 10 billion years old.  They know this by an application of what is called uniformitarianism.  The theologian in many cases has acquiesced to this aging.  But those who do not accept it have rejected it by an appeal to revelation.  And so we have the ongoing tension of naturalism and revelation.  Philosophy critically examines both to see if they know or they only think they know.

I just named the assumption we must bring into focus.  For the scientist it is called uniformitarianism (the theologian also has an assumption, revelation, and we can and should think critically about that assumption but that is a different paper).  Current science students are taught the conclusions of uniformitarianism but are rarely taught about uniformitarianism or its equally scientific alternatives.

Uniformitarianism is about change.  How should we understand change in earth’s history?  Or change in the history of the universe?  Uniformitarianism says that the forces of nature now observed have always been operating and in the current magnitude.  This means that we must explain what we now see (galaxies, stars, solar systems, planets, geological formations on planets) by forces now operating at current magnitudes.  This gives us the great ages that have become such a common idiom.  Reflect on how many times you have heard a purportedly scientific presentation begin with “millions of years ago . . . .”  Given forces now operating it would take millions of years to form rock structures or canyons or mountains etc.

The alternative is called Catastrophism which says that there have been great catastrophic changes in earth’s history that would alter the appearance and interfere with dating methods.  This view points out that the scientist cannot claim with scientific knowledge that the current forces operated in the past which was not experienced.  The scientist is stepping out of their empirical zone and making claims more akin to metaphysics and theology.  How does the scientist know what the distant past was like?  Even the recent past can be hard to pin down with certainty.  To then take this assumption, construct an origins story, and base one’s life on this origins story by rejecting the theological alternative, is not scientific or even sensible.

I am not suggesting that we cannot know which between uniformitarinism and catastrophism is true.  There can be theological ways to know and also data driven ways to know.  And if both of these come out at the same conclusion we can be confident in that conclusion.  Let me define dating methods and then give an example of what I mean about a data driven examination.

A dating method is a clock.  When we make a clock we want a device that measures change uniformly.  To helpfully measure change it must do so uniformly.  A good wristwatch measures the seconds.  And the seconds do not change.  If a wristwatch speeds up and slows down at different times it would be useless.  This is the same principle for dating methods.

The idea is that we find a natural clock.  We find something that has been changing uniformly and can be used as a measure of change in relation to other things.  For example, if trees only grow one ring a year, and also these rings record damage from fires, then we can look at a cross section of a tree and count the rings and learn when a fire occurred and compare that to other things we know about the local history.

Perhaps the best known example is radiocarbon dating, or C14.  C14 measures change by three variables.  There is the original among of C14, there is the half life of C14, and there is the current amount of C14.  The idea is that if you know the current among and the original amount you can know how long it took to go from that original amount to the current amount.  The same principle applies to the other kinds of radioactive dating.

And yet we begin to see assumptions emerge.  Specifically, the assumption of uniformitarianism.  How can we know the original amount since, according to these theories, this might have been before humans or before humans could measure carbon 14?  We have to assume that the C14 in a living creatures in the past was the same as it is today.  There it is.  See the assumption about the past?  How can we know this?  The scientist, with the scientific method, cannot know this.  Insead, the scientist is now doing metaphysics.  Do we have good reason to accept uniformitarinism?

That question returns us to what I said about data above.  We can critically examine uniformitarianism not only as a metaphysical theory but also we can look at the data it purports to explain.  Teaching our students to do this is teaching them to be good scientists and good thinkers.  Consider data from these areas: fossil beds, coal beds, sedimentary strata, mountain ranges, volcanic plateaus, ocean depths, and meteorological changes.

None of these present us with slow uniform changes.  All are examples of catastrophic changes.  A fossil bed (perhaps hundreds of fossils together) cannot form slowly over time.  If it did the animals would decompose.  Instead, a fossil bed means that these hundred animals were quickly covered so as to provide both pressure and lack of oxygen needed to fossilize and prevent decomposition.  We don’t see that happening today.  It speaks of a catastrophic event in earth’s history.

The same is true for coal beds.  This speaks of a catastrophic event covering this plant material so that it is under pressure and cannot decompose.  Consider the sedimentary strata that you see displayed as you drive past a hill that has been cut in half or as you reflect on the Grand Canyon.  The lines of demarcation are smooth and build one on the other.  And yet a slow, uniform process would not produce this.  Erosion would set in and not leave smooth lines.  To have that kind of sedimentary strata requires that these sediments were sorted out into types while under water.  And a water event covering such a large space would be catastrophic.

We can go on as we consider mountain ranges, volcanic plateaus, ocean depths, and meteorological changes that leave frozen mammoths still chewing their cud.  Each of these speak of a catastrophic event not of a slow uniform event.  And often we find materialist origin stories trying to have it both ways.  They will speak of a meteorite that smashed into the Gulf of Mexico region and caused a worldwide tidal wave that wiped out the dinosaurs.  This sounds like a catastrophic water event.  Just without Noah.

We can also find falsification of C14 ages where artifacts that we know to be only a few decades old are aged at tens of thousands of years old.  The student can apply critical thinking to these instances. This exposes that the assumptions behind uniformitarianism are not true.  And this has big implications about the casual use of ages tossed around in science class.  The critical thinker should stop the professor who says “millions of years ago when the dinosaurs ruled the earth” and ask the critical question “how do you know that?”  The answer will be something along the lines of the uniformitarisnism we have studied here.

Uniformitarianism was introduced by the geologist Charles Lyell.  And Charles Lyell was a formative influence on Charles Darwin.  It is worth our time to consider a few points about both of these thinkers since they factor so heavily into current origins stories.  Lyell said:

We have seen that, during the progress of geology, there have been great fluctuations of opinion respecting the nature of the cause to which all former changes of the earth’s surface are referable. The first observers conceived that the monuments which the geologist endeavors to decipher, relate to a period when the physical constitution of the earth differed entirely from the present, and that, even after the creation of living beings, there have been causes in action distinct in kind or degree from those now forming part of the economy of nature. These views have been gradually modified, and some of them entirely abandoned in proportion as observations have been multiplied, and signs of former mutations more skillfully interpreted. Many appearances, which for a long time were regarded as indicating mysterious and extraordinary agency, are finally recognized as the necessary result of the laws now governing the material world; and the discovery of this unlooked for conformity has induced some geologists to infer that there has never been any interruption to the same uniform order of physical events. The same assemblage of general cause, they conceive, may have been sufficient to produce, by their various combinations, the endless diversity of effects, of which the shell of the earth has preserved.”

Lyell was saying that the use of observable forces to explain origins is better than the use of catastrophes or what he considered supernaturalism.  To apply the currently observable laws of nature is surely better than appealing to the Iliad for our origins story.  And Genesis is thought to be no better.  These use pre-modern modes of thinking that we have outgrown as we now can study cause and effect.

Reflect on the chronological snobbery of such a thought.  It is as if the pre-moderns were unaware of cause and effect?  Or as if there had never been a pre-modern materialist.  But setting that aside, the contenders are not materialism and supernaturlism.  The contenders are uniformity and non-uniformity.  What Lyell does is make force absolute and is willing to alter the time needed. It is possible to make time absolute and alter the force needed, or to suggest that given features of the world were not formed at all but were created. The uniformitarian appeals to great amounts of time and limited forces now observable. This seems to be more “scientific” because it appeals only to what is now observable. But if the uniformitarian wishes to make force absolute, why can’t the catastrophist make time the absolute?”

Whether one makes force absolute or time absolute one is doing metaphysics not science and not geology.  The geological evidence can be explained by catastrophism.  And I have argued here can be better explained by catastrophism.

If we continue to scratch the surface of why did these 19th century thinkers jump to uniformity we will find the problem of evil.  Is not for scientific reasons that they did this but because of their view of God and evil.  How theological of them.

Here is the problem: Was the world originally good or has there always been natural evils like old age, sickness, and death?  This is not the question of moral evil which is often answered with an appeal to human free will.  This is a problem about evils that are not moral choices.  Sickness, old age, suffering, pain, want, famine, plague, and finally death.  Why would God make a world like that?  Darwin’s answer was to distinct God from natural evil to preserve the goodness of God.  Darwin said:

“Authors of the highest eminence seem to be fully satisfied  with the view that each species has been independently created. To my mind it accords better with what we know of  the laws impressed on matter by the Creator, that the production and extinction of the past and present inhabitants  of the world should have been due to secondary causes, like  those determining the birth and death of the individual.  When I view all beings not as special creations, but as the lineal descendants of some few beings which lived long before the first bed of the Cambrian system was deposited,  they seem to me to become ennobled. Judging from the past,  we may safely infer that not one living species will transmit  its unaltered likeness to a distant futurity. And of the  species now living very few will transmit progeny of any  kind to a far distant futurity; for the manner in which all organic beings are grouped, shows that the greater number  of species in each genus, and all the species in many genera,  have left no descendants, but have become utterly extinct.  We can so far take a prophetic glance into futurity as to  foretell that it will be the common and widely-spread species,  belonging to the larger and dominant groups within each  class, which will ultimately prevail and procreate new and  dominant species. As all the living forms of life are the lineal descendants of those which lived long before the Cambrian epoch, we may feel certain that the ordinary succession by generation has never once been broken, and that no cataclysm has desolated the whole world. Hence we may  look with some confidence to a secure future of great length.  And as natural selection works solely by and for the good  of each being, all corporeal and mental endowments will tend  to progress towards perfection (emphasis added)”

Darwin is not appealing to an observable hypothesis that can be tested.  He is making a theological claim and a psychological claim about himself.  It makes sense to him (a psychological claim about his own mind) that God would use natural evil (death of the individual) to achieve His goals than that God used special creation.

But here’s the problem: if God is perfect in power and goodness then God could have and would have made a world without evil.  Moses also was concerned to explain God and natural evil.  And Moses wrote that the original creation was very good: no evil.  Natural evil enters the world in Genesis 3 after moral evil (sin).

What this means is that Darwin isn’t doing science or theology.  He is giving his own opinions that have then shaped a century and a half of origins speculations and fueled numerous battles in public education.  If we are critical thinkers, and we teach our students to think critically, then we can read Lyell, and we can read Darwin, and we can see these assumptions and think about them for what they are.

We do not need to confuse the study of the laws of nature with the study of the origin of the laws of nature.  And we do not need to confuse Darwin’s theological speculations with the study of biology.  The problem of natural evil is a real one and is an existentially pressing one for each of us.  But we do not need to shape our science class around one answer to that problem.  Instead, we can and should teach our science students to think critically.

The influence of the principle of uniformity cannot be overestimated. But such influence means that the theories based on this principle are only as good as the principle itself. Let me end with one last example.  It is from Stephen Hawking who some regard as the smartest man to ever live.  In his last book he was describing origins.  And he said this:

If the total energy of the universe must always remain zero, and it costs energy to create a body, how can a whole universe be created from nothing?  That is why there must be a law like gravity.  Because gravity is attractive, gravitational energy is negative: One has to do work to separate a gravitationally bound system, such as the earth and the moon.  This negative energy can balance the positive energy needed to create matter, but its not quite that simple.  The negative gravitational energy of the earth, for example, is less than a billionth of the positive energy of the matter particles the earth is made of.  A body such as a star will have more negative gravitational energy, and the smaller it is (the closer the different parts of it are to each other), the greater this negative gravitational energy will be.  But before it can become greater than the positive energy of the matter, the star will collapse to a black hole, and black holes have positive energy.  That’s why empty space is stable.  Bodies such as stars or black holes cannot just appear out of nothing.  But a whole universe can.

Because gravity shapes space and time, it allows space-time to be locally stable but globally unstable.  On the scale of the entire universe, the positive energy of the matter can be balanced by the negative gravitational energy, and so there is no restriction on the creation of whole universes.  Because there is a law like gravity, the universe can and will create itself from nothing in the manner described in Chapter 6.  Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist.  It is not necessary to invoke God to light the blue touch paper and set the universe going.

The law of gravity is used to explain its own origin.  If nothing exists then neither does the law of gravity.  The law of gravity would have to then exist to bring itself into existence in order to then bring the whole universe into existence.  Now, I don’t know how the “smartest man ever” award is handed out although I do know I’m not a contender.  But can you agree with me that our students, as critical thinkers, should be able to spot this problem?

We covered four steps together as I made my case for critical thinking in science education.  We considered together the nature of critical thinking, the subject of science, the science and religion debate, and an example of that debate in the area of dating methods. Our science education must include education about critical thinking.  We can teach our students to identify assumptions and to think critically about them as part of the growth process.  This brings out the great importance in the study of the natural laws and their origins and in doing so fills them with meaning and wonder.


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