On Wednesday, January 9, 2019 at 6:49:05 PM UTC-6, Bruce wrote: > > On Thu, Jan 10, 2019 at 11:38 AM John Clark <johnk...@gmail.com > <javascript:>> wrote: > >> On Wed, Jan 9, 2019 at 5:01 PM Bruce Kellett <bhkel...@gmail.com >> <javascript:>> wrote: >> >> *> Rubbish. The fine structure constant is not computable by Feynman >>> diagrams. What might be confusing you is that QED calculations of >>> physically measurable things like the Lamb Shift and g-2 for the electron >>> depend on the value of the FSC.* >>> >> >> How is using Feynman diagrams to compute the Lamb Shift Shift (which >> depends on the Fine Structure Constant) different from using Feynman >> diagrams to compute the Fine Structure Constant? After all physics >> didn't determine the Lamb Shift from the Fine Structure Constant, they >> determined the Fine Structure Constant by looking at the Lamb Shift, in >> fact the very very fine lines in the spectrum of Hydrogen is how the Fine >> Structure Constant got its name. >> >> The following 2012 article in Physical Review letters describes a QED >> calculation involving 12,672 tenth order Feynman diagrams used to >> calculate both the magnetic moment of the electron and the inverse of the >> Fine Structure Constant and obtaining a value of 137.035999173 which is >> almost exactly the same as the experimentally derived value: >> > > That is an experimentally derived value!!!!! > > >> Improved Value of the Fine Structure Constant >> <https://arxiv.org/abs/1205.5368> >> >> John K Clark >> > > Your original claim was that the fine structure constant was computable. > But it is not computable from first principles, it is a physical constant > that must be measured. The fact that computations might be involved in > getting the value from measurements does not mean that the FSC is itself > computable. > > You have to define what you mean by "computable". The FSC is a measured > quantity, not computable in the way pi or e are computable from > mathematical formulae. > > Bruce >

Constants enter the vocabulary of physics by means of theories. *A constant is an entity of a theory,* but a constant is not an entity of nature. Nature may have *constancy*, but it's theories that have constants. *Theory != Nature. * - pt -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.