= Field
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{wiki}
<Quantum Field Theory lecture notes by David Tong (2007)> puts it well:
\Q[In classical physics, the primary reason for introducing the concept of the <field (physics)> is to construct laws of Nature that are local. The old laws of Coulomb and Newton involve "action at a distance". This means that the force felt by an electron (or planet) changes immediately if a distant <proton> (or star) moves. This situation is philosophically unsatisfactory. More importantly, it is also experimentally wrong. The field theories of Maxwell and Einstein remedy the situation, with all interactions mediated in a local fashion by the field.]
This is also mentioned e.g. at <video The Quantum Experiment that ALMOST broke Locality by The Science Asylum (2019)>.