I’ve mentioned before that one of the great pleasures of working in high-energy physics is its international nature. I find the diversity of people and cultures I encounter in the pursuit of knowledge exciting and refreshing. This week I am visiting the famous Weizmann Institute of Science, outside of Tel Aviv. Many of the physicists in my field who are here or at nearby institutions were in the United States as students, as postdoctoral researchers, or as visitors, at places where I myself was working at one point or another. Even one of my former students is here. So there are many old friends and former collaborators in both string theory and particle physics for me to meet with, and to learn from. I’ll also be giving a couple of scientific lectures during this visit.
Meanwhile, I wanted to mention a mildly interesting article that I happened to notice:
I have nothing negative to say about people doing research into exactly what babies do and don’t have intuition for at various ages, but there are two things I find problematic about the spin that is put on this story.
First, what is striking to me about human babies is not how much they know, but how little, and that point often gets lost in articles whose authors are impressed by how clever babies are. Watch a foal [= a baby horse, for my non-English-speaking readers] stand an hour after birth, and you can see how much intuitive physical understanding most animals are born with. It’s not surprising; they’d die pretty quickly without it.
Meanwhile, the other problem with this story is that knowing that things fall is not in any sense the same thing as knowing about gravity as a law of nature. On the one hand, every mildly intelligent animal “knows” that things fall (e.g. acorns from trees, balls thrown into the air) except, of course, that birds don’t, and leaves on a windy day often don’t, but hey, who’s counting. And everybody “knows” that lightweight things (leaves, sheets of paper) fall more slowly than heavy things (rocks, coconuts), though unfortunately this intuition, which everyone has from a young age, happens to be wrong. As Galileo showed easily, and as you yourself can check easily by putting a coin (or even a small sheet of paper, if you are careful to lay it very flat) on the back of a heavy book and dropping the book, all things fall at the same rate as long as there isn’t air resistance to confuse you. A law of nature is not just a general regularity, such as “things fall”; it is something much deeper, much more precise, and much more subtle than that.
The same goes for solids and liquids; we may recognize that there are objects that prevent our bodies from passing through them, and others that do not, but in what sense is that understanding anything about them? It’s a statement of “fact”; but facts, even general facts, are not laws. They are consequences of laws, but they do not by themselves reveal the nature of the law.
What is really at play in the studies of babies’ intuition is that there are some very simple and basic principles of how to interact with the world that you must know if you are to live to the age of three. If you can’t figure out that things fall, you will probably suffer a deadly fall yourself; and if you can’t figure out that there are solids and liquids, you will hurt yourself running into a tree trunk or drown trying to walk across a lake. You’d also better know quickly that you won’t be able to see in a dark place, and that the leopard that wants to eat you isn’t necessarily gone just because it has disappeared from view. I’m sorry to say, however, that essential as these survival skills are, they do not count toward a degree in physics.