Weekend Post - Changing your mind

A lot of people seem to think that changing your mind is a sign of weakness. It offends their sense of pride to think that they might have been wrong about something. I think that’s silly. Changing your mind, based on reason, rational discourse and, above all, new evidence is a perfectly respectable thing. That’s how humanity makes progress.

Unfortunately the pressure to stick with existing beliefs can be intense. We all know the stories about the Roman Catholic Church’s persecution of Galileo for his support of the Copernican view that the Earth rotated around the Sun, not the other way round. He even spent the last decade of his life under house arrest for suggesting such a thing, after being bullied into recanting his scientific beliefs. For 75 years after his death the Church banned the printing of any of his works all because they couldn’t bear the thought that they might be wrong about the nature of the solar system. OK, it was probably more because they realised that once one belief was undermined then nothing was sacred any longer. All their other beliefs might be questioned.

The other extreme is a story told by Richard Dawkins in his best-selling book, The God Delusion. He describes an occasion when he was a student. An elderly and highly respected professor attended a lecture at which a visiting American academic publicly disproved the professor’s cherished theory. According to Dawkins, who was also at the lecture, instead of arguing with the American, or just ignoring his ideas, the elderly professor walked right to the front of the lecture hall, shook the visitor firmly by the hand and loudly said “My dear fellow, I wish to thank you. I have been wrong these fifteen years.”

Clearly I’m not going to say that all scientists are as generous and open-minded and this. Scientists aren’t immune from arrogance and self-deception but their method is. The nature of the scientific method is that someone proposes a hypothesis, scientists decide how to test it and then do their level best to disprove it. Its important to understand that they do NOT try to prove the theory, they actively try to disprove it.

In fact that’s one of the key tests of whether something is genuinely scientific or not. Just ask yourself, can an idea be disproved? That’s why Freudian and Jungian psychoanalytic theories aren’t science, it’s why astrology isn’t scientific and why, despite what some political “scientists” will tell you, Marxism is many things but scientific isn’t one of them. On the other hand, Einstein’s theories of Relativity could be disproven tomorrow, they just haven’t been yet. It’s why Darwin’s theory of Natural Selection is scientific. It’s why evolution in general is a scientific concept. All it would take is a single fossil to be found in the wrong sequence and the idea would need to be reconsidered. That hasn’t happened yet.

The ability to change your mind is critical in science. Just a couple of weeks ago the New York Times published an article by Professor Richard Muller of University of California, Berkeley, a so-called “climate change skeptic” who had undergone a change of mind. Having previously identified problems with some of the research into global warming, he then undertook a thorough review of the evidence and found himself changing his mind. He said:

“I concluded that global warming was real and that the prior estimates of the rate of warming were correct. I’m now going a step further: Humans are almost entirely the cause.”

His research took into account all the objections the various climate change deniers had recently raised but he was able to reject them all. He also then published all of his findings online so the rest of us can review them as well if we want. (You should have a look, it includes data from Botswana as well.)

I don’t want this to be about climate change, that’s another issue, the point is that this scientist did what science demands. He saw the evidence, in fact he gathered much of it, he analyzed it thoroughly and saw that in certain areas his skepticism was misplaced. Like Dawkins’ professor he did the honorable thing and admitted he had been mistaken and changed his mind.

Of course life would be a lot simpler if we all had the courage to do this. I know from personal experience that my political views evolved and there came a point when I had to renounce certain labels I had used to describe my politics. It wasn’t easy to do this. I was once called a traitor for changing my mind. And that’s just politics. When certain religious groups will cheerfully have you condemned to death for changing your mind and either adopting a different religion, or worse still, abandoning superstition entirely, I can understand why many people decide to keep it secret. They continue to regularly visit their place of worship and go through the motions even though deep down they don’t believe in the core beliefs any more. This internal psychological dissonance is toxic.

Maybe if all political, religious and cultural groups were willing to accept that changing one’s mind is a natural and inevitable thing then life might be a little more tolerable. We might have slightly fewer excommunications, jihads, fatwas and killings. We might even be a bit more rational.

Weekend Post - Theories

Does anyone deny gravity? Is there anyone who believes that gravity doesn’t exist, that things aren’t somehow attracted to massive objects and, if possible, move towards them? Are there gravity-deniers out there prepared to jump off a high building to prove their point?

Of course not. No sane person denies the facts of gravity. But that doesn’t mean that there hasn’t been debate about HOW gravity works. The first great description of gravity came from Isaac Newton who described how objects attract each other and was the first to describe the mathematics of it. His “Inverse Square Law” described how gravity’s strength diminishes in proportion to the square of the distance between two objects. Double your distance from a large object and the gravitation attraction will only be one quarter of what it was. At ten times the distance the gravity will be a mere hundredth of what it was. All of this is true, certainly true enough for everyday purposes. True enough for getting spacecraft to the moon and back. True enough for almost all circumstances.

It explains things like the tides. Few people who’ve travelled to the coast have thought much about tides, why the sea level rises and falls twice a day and I suspect most people find it surprising that the water is being pulled away from the center of the Earth by the gravitational attraction of the moon. They would find it even more perplexing that the tide rises on both the side closest to the Moon AND the side furthest away. How can that be? (The first person to email me the correct explanation will get a prize.)

The problem is that although Newton described the mathematics of gravity he didn’t explain how it actually happened. He referred to objects attracting each other but didn’t say how they do this. How can a star like our Sun exert an instantaneous force on a planet like Earth from such an enormous distance? Newton didn’t know.

C/o Wikipedia http://en.wikipedia.org/wiki/General_theory_of_relativity

It took a couple of centuries for a convincing explanation to come along. Einstein’s General Theory of Relativity contained a lengthy list of new ideas but perhaps the most revolutionary was that space, the three-dimensional framework within which we operate, is indistinguishable from a fourth dimension, time. Einstein and his followers talk a lot about “space-time”, a combination of the three dimensions of space that we know and another dimension that reflects time. The less well-known thing is this was how Einstein was able to explain what gravity actually was. He suggested that space-time is curved. The reason that satellites move in a curve around the earth is because the mass of the Earth has warped the space-time through which the satellite moves. Imagine water circulating around a bath plughole and you get an idea of what it would look like if we could see in 4 dimensions. The satellite is actually taking the easiest route. This also explains how gravitational attraction appears to happen faster than the speed of light. Gravity is no longer an action that happens over a distance, it’s an object just following the simplest path.

Here’s the key point. Einstein’s “Theory” of General Relativity is a theory. It’s a way of explaining thing, including gravity. There is no “theory of gravity” because there’s no need. Gravity is like radiation, reproduction and rain, we don’t need proof that these things exist, the evidence is overwhelming. Theories are ways of explaining WHY and HOW known things happen, not that they DO happen.

The controversy isn’t with gravity, it’s with the other great known fact. Evolution.

Evolution happens, it’s as simple as that. It’s been observed in a wide variety of creatures, their characteristics adapting gradually as a result of changes in their environment. That isn’t denied by anyone who’s seen the evidence. Fossils show that creatures in the past were different to similar creatures today and the further back you go in the fossil record, the bigger the differences are.

There is no “theory of evolution” just like there’s no “theory of gravity”. There ARE however theories of HOW and WHY evolution happens and what makes species gradually change. So far, just as Einstein’s Theory of General Relativity explains gravity well, the best explanation we have for evolution is Darwin’s Theory of Natural Selection. Despite what you might think, and unlike Einstein’s theory, Darwin’s suggestion is remarkably simple to understand. It has only two basic ideas. When species reproduce they combine their genes randomly and this occasionally leads to offspring with particular strengths or weaknesses. The second element is just as simple to understand. Those random variations that give the offspring a better chance of reproducing and passing on his or her genes to the next generation are most likely to stick around. That’s all there is to it. Over time and thousands of generations these slight changes bring about a much bigger overall change to the species as a whole.

So far, just like Einstein’s theory, Darwin’s has shown considerable strength. Both make predictions that can be tested and so far no test of either theory has failed. Of course it might fail tomorrow and then we’ll need to come up with a new, better theory but so far there’s no need.

For now, despite what certain belief-based groups will tell you, we can stick with both General Relativity and Natural Selection as the best theories we have to explain the FACTS of gravity and evolution.