Well... try asking a more fundemental question.-If science can not *prove* the speed of light, consistently, by direct observation, (And by that I mean consistant with no anomalous abnormatlities. Things they can account for I will grant them a little leeway with provided they can correct for them) then using it as a constant is in fact a logical fallacy, because it is not proven as a constant. The data at the moment indicates a reduction in speed over time, which has not proven either. So using that theory as fact would be a logical fallacy as well. And while using a fallacious number may make the math pretty, in the long term garbage in=garbage out.-I am tired of science getting away with taking 'best fit' scenarios and foisting them off on the public. The average person is not a scientist, and I would wager are not able to perform the complex calculations needed to confirm what they are being told. Also, a recognition of how terms are used differently in the scientific community versus the layman usage should be addressed as well. A little more intellectual honesty and a touch of humility would be a welcome relief.