 The idea that the Planck length amounts to a minimal length in nature follows from the argument that if distances smaller than this length are resolved (say in the measurement of the position of a mass), then it would require energies concentrated in a region so small that a mini-black hole would form, taking the observed system with it – see Rovelli (2007, p. 1289) for this argument. Meschini (2007) is not convinced by such arguments, and doesn’t see that the case for the relevance of the Planck scale to quantum gravity research has been properly made. He is suspicious of the claims made on behalf of dimensional analysis. There is something to Meschini’s claims, for if the dimensional argument were true then, without realising it, Planck would have stumbled upon the beginnings of quantum gravity before either quantum field theory or general relativity were devised! However, Meschini speculates that the final theory of quantum gravity “has nothing to do with one or more of the above-mentioned constants” (p. 278). This seems too strong a statement, since a core condition on a theory of quantum gravity will be to reduce to general relativity and quantum field theory as we know it, according to limits involving these constants. Nonetheless, Meschini is surely right that the details of these dimensional arguments, and the role of the Planck scale are calling out for a closer analysis.