From Robert E. Smith, London, UK
The article by Jacklin Kwan on the number of fundamental constants there are (or should be) raises an important issue that cuts to the heart of physical theory: are constants genuine features of nature, or are they artefacts of our descriptive language?
It seems to me that the answer lies not in counting constants, but in asking what role they play. Every physical “constant” serves one of two purposes: either it fixes a scale that converts between human-defined units, or it encodes a deeper invariance that remains when the units are stripped away. Only the second category deserves to be called fundamental(18 October, p 40).
