ABSTRACT
Physicists have come to appreciate the existence of certain universal constants of nature like the velocity of light, Newton’s constant, the elementary charge, Planck’s constant etc. These are numbers that cannot be calculated from first principles. They have to be obtained from measurements and their values set the scales that characterize our universe. First we show how these constants can be used to define a complete and consistent system of units. In the second section, we take a step back and ask whether these constants are really universal, or just the parameters that appear in our theories and therefore only reflect the present state of science. In the third section, we play around with these constants to explore to what extent these natural scales mark the domains of validity of particular theories. We conclude by describing the Planck system of ‘natural’ units and discuss its interpretation. Indeed, the arguments presented in this chapter suggest that man is not the measure of all things, rather the arguments constitute a modest plea to bid farewell to anthropocentrism.
