You can believe what you like but progress needs truth




You can believe what you like but if you want to make progress truth matters. The story of the Global Positioning System (GPS) illustrates the point. Imagine you are standing in front of two long case clocks, you stop the pendulums and set them swinging again so that they are in sync. It will not take long before you notice the swing of the pendulums is drifting apart. A 300-year-old clock with a seconds pendulum can be made to run accurately to less than one minute a week, but this still means up to 8 seconds drift a day. Now if you replaced the pendulum clocks with two synchronized atomic clocks, you would have to wait something like 100 million years before either clock has drifted even one second from standard time.

Satellite navigation (Global Positioning System) uses the accuracy of atomic clocks to calculate your position. Some of those clocks are on satellites orbiting at about 20,000 km (12,540 mi) above the earth, and they all need to keep time to billionths of a second to calculate your position to an accuracy of 5 meters. This precision shouldn’t be a problem because the atomic clocks used are much more accurate than required. However, Einstein came up with the idea that speed and gravity affect time (Special and General Relativity). He predicted that moving the clock into orbit where it is moving faster than the earth’s surface would result in it running slower than its twin on the earth. Einstein made this worse by also predicting that time is affected by gravity, and because gravity is lower for the clocks in orbit, they will run faster. The net result is that Einstein’s theories of Special and General Relativity predict that “the satellites’ clocks tick faster by about 38 microseconds each day.” (NASA)

For most people, Einstein’s ideas contradict their everyday experience. Watches do not run slower when you are driving. His theories defy common sense, are mathematical, and it is easy to ignore them. You can decide Einstein was wrong and because you are not using his ideas to do something it does not matter. In everyday life, people don't get a chance to apply their belief in Einstein's theories, and there are no consequences for believing Relativity is right or wrong. However, many people now use GPS. They want to get to their destination and therefore need the GPS to be accurate to 5 meters or so. GPS has Relativity correct built in but imagine that the designers decided to add a switch so that you could choose to switch it on or off. Now you have the choice but you also the consequences of that choice. If you believe Einstein was wrong, then you should switch Relativity correction off, and if you are right, the GPS should be more accurate because it is not adding an unneeded false error correction. If you did this according to NASA “position errors would accumulate so quickly that the system would be useless for navigation in a matter of minutes.” The consequence of applying your belief and switching off the Relativity correction is that GPS is unusable. You might still reject the Einstein’s theories, but now your desire for a usable GPS system pushes you to accept them. You might not want to believe in them, but they make the system more accurate. It becomes much more difficult just to dismiss them because if they weren’t correct why would they make the system more accurate.

When you have a goal like building a GPS system accurate to 5 meters you need to use ideas that will progress you towards that accuracy. You might not want to believe some of those ideas are true but if when they are tested, they deliver then your goal forces you to. The moral of all this is that to make progress; you need truth. Having a goal like "accurate to 5 meters" forces you to test ideas and apply ideas that help you towards your goal and reject those that don't.