Friday, April 13, 2007
Does Science Provide any Real Answers?
Despite what you may have been led to believe in science class, physicists don't have all the answers, though not many of them seem able to admit it.
In all my time in high school science, not once did I hear a physics teacher say the following:
"This theory provides a model of what is going on, but what is actually going on may be quite different. We don't really know."
Too bad, because that would have helped me realize that science, and physics in particular, is in the business of providing MODELS, not true understanding.
Physicists, over a period of hundreds of years of trial and error, have stumbled
upon some mathematics that, when applied to the behavior of objects, can model and predict the behavior of those objects. They tried this theory, and that theory, and each time compared the theory with the experiment. Along the way (and this is rarely emphasized) thousands of theories that didn't fit the experimental data were thrown into the garbage can. Once in a great while, a scientist came up with a theory that seemed to fit the data. Even more rarely, a theory was devised that not only agreed with the experimental data, but also, amazingly, correctly predicted things that hadn't yet been measured. Einstein's theories of special relativity and general relativity are two examples.
But do these mathematical theories and models give any real understanding of what is going on?
Well, not really.
Take gas pressure, for example. The mental picture we are all given in science class is of a bunch of little particles all bouncing around and pushing on the side of bottles to create pressure. It's a nice, convenient model. However, if you look deeper, you run into quantum mechanics which says that actually, particles sometimes behave like waves. Tiny particles are governed by strange laws and they behave irrationally. This means that the model we have of little particles bouncing around and pushing on things while convenient,
tends to sweep under the covers what is actually going on.
Now take gravity. The picture we are given in this case is of two bodies such as the sun and the earth attacting one another. Do you remember receiving an explanation of WHY they would choose to do that? Didn't think so. And, it turns out that this naive picture may not be complete anyway. If you dig deeper, you will find out that the theory of general relativity tells us that the attraction can be modelled by looking at a type of geometric curvature in four-dimensional space-time. Similarly, we have models that explain electrostatic attraction but they don't tell us WHY particles with a
positive charge attract those with negative charge (and try asking a science teacher what charge actually IS).
Richard Feynman, a very good (and sadly dead) theoretical physicist, once said that nobody understands quantum mechanics. Since quantum mechanics seems to accurately describe the behavior of small particles, and big things (we are told) are made of lots of small particles, this effectively means that nobody REALLY understands ANYTHING in our physical universe.
To give another example that you don't often hear mentiond, physics explains nothing about life. You can plug numbers into any equation you like, even a so-called "theory of everything", and you will not be able to explain why, if person A farts, person B laughs. Until you can do that, my fine feathered friends, I would argue that you don't really have a theory of everything.
So if you had a tough time in science class, don't worry. Perhaps your brain was hurting because you were trying to truly understand things that aren't understood, even though the teacher might have been pretending
that they were.
And if you couldn't follow along and understand the theory or the model they were trying to teach you? Well, remember that you were trying to understand a theory that was created by a person of genius after many years of careful study, and most probably after they had thrown out many other similar theories.
So the fact that most people don't understand physics is, well, understandable.
Time for today's quote, in honor of Kurt Vonnegut, a man who made my life harder to understand yet easier to live:
I have told my sons that they are not under any circumstances to take part in massacres, and that the news of massacres of enemies is not to fill them with satisfaction or glee. I have also told them not to work for companies which make massacre machinery, and to express contempt for people who think we need machinery like that.
Until the next time, gentle reader, I remain,