The whole world should switch to the metric system.

Well first off, thanks for taking the debate. I'll address what you said first before moving onto some points of my own. You seem to be suggesting that if it is too difficult for one country to change something, it shouldn't be done. I think I need to remind you that the USA is the only country in the western world who does not officially recognise SI units as the primary unit of measurement. If you're arguing that most of the world uses the imperial system, that is outright wrong. In fact as of 2006, 95% of the world's population live in metricated countries. That's right, 95% (http://en.wikipedia.org...). I suppose it is understandable to disagree if you are from the USA where you have been using your imperial system your whole life, but hopefully you can recognise that the vast majority of the world do not use your system of measurement, not only this but your system of imperial measurement is almost inconceivably flawed. The idea that units of measurement SHOULDN'T be based on science and logic is outright ludicrous. Everything you see is based on these measurements, from the calculations of microwave heat, to the structural integrity of the walls of your house and everything in between. The idea that these units should be chosen seemingly at random is baffling. It simply is not possible to have any sort of reasonable scientific advancement with a system of measurement so abrirtarily defined. This brings me to my first point, the fact that a single unified system of measurements is beneficial to humanity as a whole. Accepting the fact that the vast, vast majority of the world uses the metric system, the benefits of having just one system are many, although for the sake of saving space, here are two main ones, broken into scientific use and general use. A) GENERAL USE A unifying of ideas that stretches beyond cultural barriers, such as in general conversation talking to people from the USA it is usually bothersome to have to explain that when you weigh, say 83 kilograms that that is about 185 pounds. A world with a single system would not need this, although granted it would take a while for the habitual use of the imperial system to wear out. B) SCIENTIFIC USE Actually a few times, the use of two systems of measurement has caused serious damage to scientific progress and also endangered the lives of people. I point to two examples in very recent times -In 1983 a Boeing 767 jet ran out of fuel in mid flight because of two mistakes in figuring the fuel supply of Air Canada's first aircraft to use metric measurements. (http://select.nytimes.com...) -In 1999 NASA lost a $125 million Mars orbiter because one engineering team used metric units while another used US customary units for a calculation. (http://edition.cnn.com...) These two disasters were entirely preventable, and in hindsight, they are almost laughable that they happened. It seems strange that NASA could manage to lose such an important piece of equipment through such a simple error, however it is sadly suprising almost to the point of depression that this was due simply to conversion between two units when it wasn't even needed.