I’m struggling to put the Higgs mechanism into the context of established physics. It seems to me that the concept of ‘mass’ is far from immutable. Physicists often qualify mass as ‘effective’. An example is electron mass in a semiconductor, where effective mass may be positive, zero or negative, depending on electron energy relative to the band structure. Other examples of qualifying mass as ‘effective’ have been recently highlighted with regard to the http://mag.digitalpc.co.uk/Olive/ODE/physicsworld/LandingPage/LandingPage.aspx?href=UEhZU1dvZGUvMjAxMi8xMC8wMQ..&pageno=MjU.&entity=QXIwMjUwMQ..&view=ZW5[/PLAIN] [Broken] 0aXR5] Higgs . These are for: high-energy photons propagating in a plasma; inter-electron repulsion with Debye screening; a solid moving in a liquid that is non-viscous and without vorticity. And, with moving objects, relativity teaches that we must distinguish between ‘mass’ and ‘rest mass’. In all the situations above where 'mass' is qualified it seems to be because something else gets in the way of, or complicates, a direct measurement of inertia or momentum --- a crystal lattice, a plasma, virtual photons, a liquid, and relative motion. Does the Higgs mechanism that endows everything with mass do so with no such complication?