Thursday, February 1, 2018

The Tentative Nature of Science

Yesterday in my methods of teaching science class, we took the whole class meeting to wrestle through the nature of science. By "nature of science," I mean trying to understand what makes How do scientists approach their work? What are the ground rules for doing science? What are the limits of science?

I love this shirt...and, yes...I've worn it to class... [CC BY-SA 2.0]

It's a fun challenge each time I teach this course to try and help the future teachers I serve shift their thinking. So many of them come into this course with strong, pre-conceived ideas about science as a discipline. I'm convinced that partly this is due to a broad cultural (mis)understanding of what science is and how it works...but I think part of it is something that we, teachers, have perpetuated.

I know that from my own experience in school, science was often taught as "the facts"--as if you could just memorize the facts, and then you would understand the way the world works. From the science autobiographies I have assigned my students to write over the nineteen times I've taught this course, I believe that this is a very, very common phenomenon in schools. Teachers often seem to approach science this way: it's a body of knowledge to memorize and master.

Okay, is a body of knowledge. There are scientific ideas: laws, theories, hypotheses, mental models, etc. All of these together make up the body of knowledge that we call "science."

But science is more than just a body of knowledge.

In class, we talk about how science is also something you do. What does a scientist do? They use scientific methods (such as observation, measurement, inference, prediction, hypothesizing, experimentation, and data analysis, to name a few) to investigate different parts of the world around us. Leaving out this part of "science" might be part of why students in school see science as a collection of facts to memorize.

But there is another important part to the "nature of science" as well. This is the part that I call the "attitude" of science--science as a way of knowing about the world. And this is the part we really focused on in class yesterday. I share with students the habits of mind that scientists embody in their work: curiosity, wonder, skepticism, intellectual honesty, openness to new ideas, and humility. And in the process, we explore the way that scientific knowledge is developed.

The way I frame it for them, science is based on facts, but the challenge is that scientific knowledge is simultaneously tentative and subject to change. The definition we use in class is something like this: A scientific fact is a proposition based on evidence or data. As new evidence is collected, our understanding of the facts might be strengthened, or we might reconsider our understanding of the facts.

Some students don't like this idea very makes it feel like science is a little too soft somehow. So I try giving them some examples:

  • It is a fact that every organism (living thing) is made out of cells. I can't prove this to you, because I haven't examined every single living thing on planet Earth, but there is a HUGE amount of evidence that supports this proposition. Every living thing human beings have examined so far has been made out of cells, so this fact is widely accepted as correct. However, if some scientists discovered a new type of organism that is not made of cells, this would be an opportunity to rethink that fact--and our mental model for organisms might have to change.
  • Best evidence suggests that matter is made out of atoms, but I can't prove this too you. The scientific consensus about the nature of atoms has evolved through time. Beginning with John Dalton's (1800's) atomic theory--which pictured atoms as simple spheres that interacted in simple, straightforward ways--through the discovery of electrons, and protons, and neutrons, and a whole sub-atomic zoo of different kinds of particles--to the probabilistic electron cloud model, the facts of what atoms are like has evolved over time, as new discoveries were made.
  • If I drop something, the fact is that it will fall to the ground...every time. There is a massive amount of evidence that supports this proposition! But if I would drop a ball, and instead of falling to the ground, it would go whizzing up into the air instead, this new evidence would challenge us to have to explain this observation. The facts of how gravitational force works would have to be reconsidered. The Law of Universal Gravitation is the best explanation we have for why dropped objects fall to the ground, because it explains what we observe, and allows us to make predictions for future events that we have not yet observed.

This is a pretty huge paradigm shift for some students. So many of them have been taught (either explicitly, in school, or implicitly, through cultural inputs) that science is all about proving things. It's kind of like I'm pulling the rug out from under them in some ways.

I'm inviting them to be curious.

I'm inviting them to wonder--in every sense of the word.

I'm inviting them to be skeptical and want to see some evidence for claims.

I'm inviting them to be intellectually honest as they report the things they observe.

I'm inviting them to be open to new ideas that might challenge their current thinking!

I'm inviting them to be humble about what they know, and what they don't yet know.

This is the tentative nature of science!

In my Twitterfeed this morning, I saw this tweet from the always-clever, sometimes-obstreperous (and definitely-deceased!) theoretical physicist, Richard Feynman. It's a good one for summing up my best thinking about this topic for now...

It's an honor and a privilege to work with these students, and I hope that we'll have a great semester together exploring teaching science by doing science together this way.


  1. And all of those skills....curiousity, critical thinking, integrity and wonder can all be applied to every area of their life...these are skills not only for science but for life....this is how we teach our students to be lifelong learners....something we see in many school's mission or vision statement. Thanks Dave!

    1. Fully agree that these are habits of mind that stretch far beyond the domain of "science!" Your comment makes me think of how important it is to teach science at all grade levels--in the same way that we should teach literacy skills, and mathematics, and social studies, and the arts, and...all the disciplines. Each has peculiar approaches and traditions that help us to develop as whole people.

      Thanks for taking the time to read and comment!