What will they say in the future about our theories? Will they think we’re as crazy as those who thought that Earth was the center of the universe, and flat, and sitting on top of four giant elephants, perched upon a giant flying sky-turtle?
I may have gotten a little carried away there. Anyway, I wrote this paper a few months ago for a class on the history of science, and I’ve edited it slightly to respond to my instructor’s remarks.
A great astronomer once said “the Cosmos is all that is or ever was or ever will be.” All of our science, our astronomy, our cosmology, our evolutionary biology, our history, is based on the culmination of hundreds of years of research and theory. We’re pretty sure – incredibly so, as a matter of fact – that it’s right. But so thought the ancient astronomers about their theories of our universe – geocentricism, the idea that all the stars were on a shell spinning around the earth, flat earth theories, young earth theories, and so on. What makes our theories different? How can we claim to be right, when those before us felt just as strongly about their position?
Well, for one, we have the ability to gather better evidence. We can see that the stars are not a shell orbiting around us, but individual bodies. We can use our telescopes and other instruments to measure the orbits of the planets. This allows us to tell that we’re orbiting around the sun. We can see other galaxies, allowing us to learn more about our own. We have better equipment – we can be certain that at the very least, we are more right than the ancient astronomers are – but will our theories be disproved in the next millennia, as better equipment and methods are discovered?
I don’t think so. Unlike ‘scientists’ of centuries ago, we can test our theories. We know the limits of our methods. We know what we don’t know. This contrasts with the ancient astronomers: they made claims that they couldn’t possibly have proven. They couldn’t have known that the sun orbited the earth, as they didn’t have the tools to accurately measure its motion. They couldn’t have detected that the stars were all the same distance from us and suspended from a spherical shell, because they didn’t have the method we have of measuring distance – it would be silly if they did, because that method directly contradicts the theory they’d be testing with it. Anyway, it is quite obvious that they couldn’t test these theories, because both of these aren’t true – but nonetheless, they theorized it. This was the science of the time. By contrast, if our theories were wrong, we would know it. We have the tools to detect the locations of stars and planets, and use this to confirm that our theories of gravity and cosmology are accurate to within an absurdly small margin of error.
The argument could be made that all of our science is wrong. Bertrand Russell proposed that “we may all have come into existence five minutes ago, provided with ready-made memories, with holes in our socks and hair that needed cutting.” Our assumption in science is that this is not the case. More generally, we assume that the universe is bound by certain laws – if I may use another quote from Carl Sagan, paraphrased, we live in a universe where things change – but according to patterns, rules, or as we call them, laws of nature. These laws must not be violated, and as long as they aren’t, our science is certain. If those laws are allowed to be broken, then our science could be completely wrong – but there’s no evidence that that is the case.
So, no, our theories of the cosmos will not seem wrong in a few hundred years. They will without a doubt seem incomplete – but not wrong. What we know is true, though it will be expanded on by future generations. There are a great number of open problems – dark matter, dark energy, the great attractor, string theory, a grand unified theory of the four fundamental forces, string theory, to name just a few. But answers to these problems won’t change the answers we already have, just extend them. Our tools will seem limited, but our methods will (hopefully, if there still is a scientific community) be the same as those they’re using. The scientific method is a way – the only way – to go from observations to theories. We know that we’re right and those who came before us were wrong because of the scientific method – and those who come after us will know that we’re right because they’ll be using that same method.