How to Make Your Own Analogies

How to Make Your Own Analogies

Analogies can help any time you want to communicate what you know, teach someone something they don’t understand, or (perhaps best of all) teach something to yourself so that you understand it better. The good news is that analogy-making comes naturally to human beings. That said, there are some steps to follow to be more deliberate in your creation of high-quality analogies.

Step 1: Figure out the property or characteristic you are most trying to convey about a particular domain

Let’s say you are Feynman and want to explain to a group of laypeople how the human eye experiences and processes light waves. It’s an extremely complex concept. But he starts by homing in on the property he most wants to communicate—the fact that waves are experienced in a particular way when you are immersed in them, and that you can infer characteristics about the entire waves’ motion by experiencing it in just one point.

Step 2: Find something concrete and ordinary to map this characteristic onto

You are probably already so used to thinking of sound or light waves as water waves—because scientists have been pointing to this analogy for centuries. So you draw on this association and say that light waves behave similarly to waves in a pool of water. Now, how do you communicate the above characteristic? Feynman once said that you could imagine a little fly floating on the water. The fly would bob up and down as the waves passed over it. This bobbing up and down would be its experience of the wave, but if it was a smart fly, it could gather all this data and begin to make a theory about what the waves were and where they were coming from, even if, being so small, it couldn’t gain a bigger picture.

Feynman went on to explain that this is precisely what the eye does when light waves enter It: the eyes detect the stimulus (analogous to bobbing up and down) and the brain pieces the data together to create a mental map of where they are coming from. In this way the brain constructs an internal model of the visible world around it. It’s the same as the fly coming to understand the waves that are moving it up and down.

Step 3: Adjust or discard your analogy if it isn’t working!

Your analogy’s success will depend on the quality of the relationship between the two things you are comparing. If you are trying to describe light waves hitting the eye using an analogy of an octopus in a supermarket buying cantaloupes, your listeners will exhaust all their brainpower just trying to guess how the two things fit together. Be aware, as well, that an analogy is limited—it is highlighting just a single aspect of relationship or similarity. In this example, the wavelike characteristic of both water waves and light waves is relevant—other properties are not. In this example, a fly has very little in common with a human eye, other than the fact of it intelligently processing data. If your listener or student is hung up on the idea of a fly, then forget the fly and choose something else!

Other interesting science metaphors and analogies you might find helpful—look closely and see if you can identify the single characteristic that is being highlighted, and the exact relationship between the things being compared.

• The atom is like a tiny solar system (naturally, this analogy is useless if the person hearing it doesn’t know what a solar system is . . .).

• The spread of an infectious disease is like the spread of a wildfire. Only a small spark is needed, but if enough “fuel” is encountered, the spread could be exponential.

• Receiving a fecal transplant is a little like sowing wildflower seeds into bare soil.

• Taking a probiotic supplement to boost the gut microbiome is like pouring a bucket of water into the ocean to boost sea levels.

• A proper science lesson is like an enzyme—it instigates changes in the student’s mind akin to a chemical reaction by using a device (such as an analogy) to speed up and trigger that reaction. But the understanding was always something the student was capable of, and the raw material was always there! The teacher/device, just like a catalyst, remains unchanged.

• Metabolism is like an engine.

• Determining redshift by spectroscopy is a bit like identifying a fingerprint on a balloon that has been stretched (note, this analogy is so good that you probably understand the concept being explained even though you don’t know what redshift or spectroscopy is!).