Language is such a beautiful thing. It is at once both completely arbitrary and completely foundational to the way that we construct our understanding of the world. It is both a random accident of history and culture, and the set of fundamental building blocks from which we build our most complex theories of logic and science. To anyone who likes to believe in the rationality of thought or the logic of nature, language is the ultimate confound: because language is ultimately driven by caprice and random chance.
Philip Pullman playfully took advantage of this in his book, The Golden Compass. He recognized that English is a mutt language, and as such borrows haphazardly, without any apparent rhyme or reason, its word roots from various other languages. So, when describing an alternate “parallel universe” he imagined what the English language might look like if certain common, every-day words had simply used (for example) the Arabic root instead of the Greek. As a result he comes up with “anbaric energy” as the type of energy that was first observed by the effect that you get when you rub amber against cloth. The Arabic root for amber as anbar. Of course, the Greek word for amber is ήλεκτρον (élektron).
English abounds with examples like this. We sit around and watch the television, never thinking about what a Frankenstein monster that word is: it mixes the Greek word for distance τέλε (tele) with the Latin word for seeing (visio). If things had only been nudged the other way, say about 100 years ago, we could have used the Latin word for distance (disto) with the Greek word for seeing ὀπτικός (optikos), and we would all be sitting around watching the distopticon.
But this arbitrariness goes even deeper than just labels and word-roots. Sometimes it can get to the very core of the way we think about things.
Have you ever wondered why electrons have a “negative charge”? The two charges in electromagnetism are called “positive” and “negative” but there is nothing inherently “plus” or “minus” about either of them. The two labels could be flipped: that is, we could call the charge that the electron has the “positive” one and the charge that a proton has the “negative” one. Indeed we could even use completely different labels altogether. There is absolutely no reason that an imaginative physicist could not have called the two electrical charges the “red charge” and the “green charge” or the “top charge” and the “bottom charge.” (And indeed, more imaginative physicists did, in fact, do something like this when naming properties of quarks.)
So why is the charge of electrons called the “negative” charge?
Benjamin Franklin was doing a very well-known experiment (well-known even before his own time) where he rubbed wool against wax and found that they attracted one another. At the time, there were many ideas floating around about why this happened, but Ben decided that the best explanation was that there was some invisible “fluid” or substance that was exchanged when these things rubbed together. Since the wool is coarse and the wax is smooth, he assumed that the fluid was rubbed off the wax by the wool. Thus: the wool had an excess of this supposed fluid or substance, and the wax had a deficiency. As a result, he said that the wax had a negative charge (i.e. a deficiency of the substance) and the wool had a positive charge (i.e. an excess of the substance).
Of course since then we discovered that the interaction goes the other way: the teeny tiny electrons come away from the wool and build up on the wax. But since everyone was so used to talking about the charge of the wax being “negative” and the charge of the wool being “positive”, rather than changing the names they simply decided to call the charge of the substance that got transferred a “negative charge.” Problem solved.
So ultimately, one of the basic “facts” that we know about science–that electrons have a negative charge–is only discussed in the way that it is today because of a mistake that Ben Franklin made over 200 years ago.
But I suppose what we name the charge of electrons doesn’t ultimately matter. As long as I can use them to run my anbaric distopticon.