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Last year we had a number of great talks on some of the differences between light-front and instant-form quantum field theory. One of the things that was never clear to me is that the dynamics of free and interacting field theories live on inequivalent Hilbert space representations of the algebra of the fields. My interpretation of this is that the notion of kinematic subgroup, which is central to the meaning of Dirac's forms of dynamics, does not trivially generalize to the field theory case. This talk is an attempt to resolve some issues related to this observation by assuming the existence of a local quantum field theory with all of the expected properties. This avoids issues related to renormalization and rotational covariance. Using these assumptions I will discuss how kinematic subgroups can be realized, the equivalence of theories with different kinematic subgroups and a consistent treatment of the vacuum and spontaneous symmetry breaking. The path to this from the ``perturbative treatment'' requires tackling the challenging problems of non-perturbative renormalization and rotational covariance which remain open problems. Webinar at https://us02web.zoom.us/j/81572103194?pwd=eE1QVWZFc1hWbWszZ2N0RW1iWHFBZz09