This thread is not about what an inertial force is, what Einstein thought of it, what you think GR has to say on it etc. This thread is whether you think that inertial forces can be thought of as "real" or not. And. of course, that will be a function of your own personal opinion on how the term "real? should be interpreted, at least in this scenario/case. The definition of inertial force is well known and never debated. For those who don’t know the definition please see http://home.comcast.net/~peter.m.brown/gr/inertial_force.htm In that page I've described various viewpoints from some well-known physics textbooks on mechanics general relativity and cosmology. Before any of you claim to know how it's viewed in the physics community please see the quotes at the end which expresses one side of the viewpoint. My question for you is - Do you believe that the gravitational force cannot be thought of as a "real" force and must therefore be called, at best, a pseudo force? Or to phrase it another way - How many of you believe that if a particle is accelerating under the action of a field for which the 4-acceleration on the particle is zero that any attempt to define a "force" on the particle must imply that it should be thought of/defined as a pseudo-force? If you're able to vote either yes, nor or other then please do so. or example; "Other" might mean that you don't know what "real" means or that its a bad word to use in physics. Note - No. This is not a trick question.