Maximal Acceleration, Reciprocity & Nonlocality

The existence of a fundamental scale is expected to be key feature quantum gravity. Many approaches take this property as starting assumption. Here, instead, we less conventional viewpoint based on critical inspection both principles and kinematic laws. We point out that rigorous arguments suggest more urgent need revise known theories incorporate acceleration already in flat space. reciprocity principle can naturally do so. In addition noticing links with string theory, argue the implies an infinite-derivative generalization Einstein-Hilbert action makes gravitational interaction fundamentally nonlocal, thus providing guiding could lead us towards formulation consistent theory