When I was a science teacher I had to teach subatomic particles to all the classes regardless of ability or interest. For the bottom set GCSE class we used to sit companionably either cutting out circles to make into electrons, neutrons and protons, or, if the class was chill enough, we’d use plasticine and go for the 3D version. Invariably, the question would soon arise “Miss, when are we ever going to need this?”.
“Good question!” I’d say, like all teachers who know that the shortest questions require the longest answers. “You’ll probably never need it for your day-to-day life, but sometimes it’s nice to know a little bit about how things work under the surface.” Sometimes that’d get an eye roll, sometimes we’d chat a bit more about what we really need to know about to get by in life.
Clearly, we don’t need to know everything about everything to get by in life. A working understanding of the things that we have to interact with is enough. In any case, we can’t possibly process all of the information in the universe, so it’s positively unhelpful to try.
So far, so obvious. It’s so obvious we almost don’t notice. The implications are huge though. Nothing we understand is reality. Nothing we know is truth. It’s all a model. In our heads. And that is something that evolution has selected for. As we can’t know or process all the data that we’d need to have to know “the truth” it’s far more efficient to have a good model. (Mostly, knowing the truth doesn’t help us anyway. What good is it to know that my table is made of protons, neutrons and electrons? If I had to think about that every time I put my dinner down I’d never get anything done.)
Why do children draw round heads, round bodies and stick arms and legs? That’s their model for the human body. Leonardo Da Vinci had a more refined model. Some might say it was closer to the truth, but his anatomical drawings still leave much unspoken. They say nothing about the biological pathways within the body depicted, the language the person spoke, or the smell of their skin.
“All models are wrong, but some are useful”, said statistician, George Box. Most of the useful models we use are so endemic that they are perceived as truth. For example, we may not question that time flows linearly and we look forward into the future, but some cultures use a different model. “The Malagasy imagine the future as flowing into the back of their heads, or passing them from behind, then becoming the past as it stretches out in front of them. The past is in front of their eyes because it is visible, known and influential” says Richard Lewis in When Cultures Collide. (If you want to get closer to the truth about time, Carlo Rovelli’s book The Order of Time takes a deep, dizzying dive into the quantum world where it becomes quite untethered.)
So what’s my point? My point is to never feel bad about using models. In every conceivable way they are reality. Furthermore, it’s not a compromise. It’s helpful, it makes things manageable. In this respect, as Donald Hoffman says “Fitness beats truth (a good model is better than reality)” – as per his book The Case against Reality.
The trick is to ensure you are using a model that’s right for the task at hand. Be it plasticine or potential energy surface (PES) calculations.