KNOWLEDGE OR CERTAINTY

It's July 16, 1969 and the start of the greatest voyage in our history: Apollo 11 is launched from Cape Kennedy atop a Saturn V booster (left). Four days and over 200,000 miles later, Neil Armstrong and Buzz Aldrin become the first people to set foot on another world (right). And all thanks to Newton's Laws of Universal Gravitation and Motion, exquisitely accurate at non-relativistic 'everyday' speeds.

Politicians and religious leaders invariably state with

certainty that their beliefs and preachings are the absolute truth. Guest blogger ANDY FLEMING investigates knowledge and certainty, and in the process reveals how a society that dispenses with true scientific scepticism inevitably ends in tragedy.

All of my life I've been fascinated by science, and although I'm not a scientist (I was however a laboratory analyst at ICI for many years, and I am an amateur astronomer) I still consider science to be the best human method for explaining how we, and the entire cosmos came to be. Unlike many other areas of human endeavour such as religion, our scientific theories, although still only approximate descriptions of reality, are testable, falsifiable and most importantly, can be verified by peer review. This cannot be said of many other academic disciplines, as instead of logical, rational thought, they rely on each individual's belief systems and their hypotheses are hence not testable in the real world.

Humankind's scientific theories are however, at best only approximations of reality, albeit often exquisitely accurate approximations. Over decades and centuries they have been developed and amended in the light of better data and evidence. For example Newton's Laws of Motion and Universal Gravitation were perfectly adequate up to 1915, and indeed are still used in determining a spacecraft's trajectory. Such an example is NASA/JPL's's New Horizons mission to Pluto, due to arrive with perfect accuracy to the nearest second at that distant dwarf planet in 2015. However, Sir Isaac Newton cannot be placed in the driver's seat in very strong gravitational fields or at relativistic velocities (speeds approaching that of light), due to effects including time dilation and Lorentz length contractions. And Newton’s speculative contention that time is a universal constant was proved incorrect by Einstein. It is the speed of light that is a universal constant.