30.04.2019 |

Episode #6 of the course How science works by Benjamin Keep


Welcome back.

Today, we tackle the often unsung hero of scientific research: the scientific instrument.

Imagine science without instruments of any kind. No telescopes, no microscopes, no litmus paper, no particle colliders, no thermometers, no vacuum chambers, no scales, no artificial pumps … Does it still feel like science?

Consider the atom. No one has ever seen an atom—at least, not with the naked eye. And yet, we’re all pretty darn sure that atoms exist. Nearly all the research that has developed the modern idea of the atom—the structure, nature, and kinds of atoms there are—has come from research with instruments. And yet, instruments are often left out of traditional conceptions of how science works.


The Many Roles of Instruments

Some instruments illustrate new phenomena. It’s the early 1820s, and Michael Faraday created an electromagnetic motor by bringing a magnet close to a closed electric circuit. The motor demonstrated an unexplainable phenomenon that scientists would later (in the 1870s) call electromagnetism. In addition to writing articles detailing his experiments with the motor, Faraday also created replicas of his instruments, boxed them up (along with instructions on their use), and sent them to several leading scientists of the day. Which one, the article or the instrument, was a more powerful way of creating knowledge? Scientists may disagree about how to explain what’s happening with the motor, but with a little patience and luck, they can replicate the phenomenon. The motor demonstrates something that needs to be explained.

But instruments can also measure. Consider the thermometer. We can certainly just feel temperature—the patient’s forehead feels hot or cold—but the thermometer makes the concept of temperature far more precise. The instrument standardizes the measurement so different research groups in different places and times can meaningfully compare their results. Of course, as we saw in our last lesson, instruments can also serve as models, representing phenomena and relationships in the world.

Many instruments serve multiple functions. A microscope enabled scientists to witness completely new phenomena, like tiny creatures never seen before. They can be used as measuring instruments: Think of a biopsy that looks for cancer in surgically removed tissue. And they can be used as models, such as to illustrate and study how light refraction works.


Understanding the Instrument

Instruments have a peculiar quality: They box stuff up. Yes, instruments can be taken apart, rebuilt, and replicated, but if you give me the instructions and the materials to build an electric motor, and I can’t get it to work like you said it should, whose fault is it? Knowing what we know now about electromagnetism, the answer is clear (my fault). But when new instruments are being developed, there are plenty of questions: Why should I believe that the instrument works in the way that you say it does? Is it really measuring what we think it’s measuring? And how do we know when it’s broken?

Several years before Galileo got into trouble with the Catholic Church for promoting the idea that the earth moves around the sun, he built a telescope and started looking at the sky. He made a startling discovery: Jupiter had moons. The first night, he spotted four small dots near Jupiter and assumed they were stars. But as he viewed them on subsequent nights, he realized these dots were moving. Excitedly, he asked other local astronomers to take a look at what he had found. Their response: “Are you sure that’s not just some dust on the lens?”

If this criticism seems silly now, it’s only in retrospect, knowing that subsequent observations would show that Galileo was right and the other astronomers were wrong.

It’s easy to think of science and engineering as distinct: Science is about creating new theories about the world, discovering new phenomena, and positing (and evaluating) causal explanations. Engineering is about building things to accomplish specific goals: Build a bridge that can carry up to 1,000 tons using these materials; build a spacecraft that can fly to the moon. But the combination of engineering and science (sometimes referred to as “techno-science”) has proven to be a powerful approach for generating knowledge. New instruments bring new phenomena to the fore, standardize our measurements, and otherwise serve as tools for thinking with.

Next time: a chat about method.


Questions to ponder

Consider Faraday’s motor. Does the motor possess knowledge by being able to replicate a phenomenon? If not, where does the knowledge about the phenomenon exist? And what kind of knowledge is it?


Recommended book

Thing Knowledge: A Philosophy of Scientific Instruments by Davis Baird


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