Galileo’s Principle That All Bodies Accelerate At The Same Rate Depends On An Extension By Einstein Of Rock The Psychologist’s Theory Of Induced Self-Motion
Authors: Snyder Douglas Michael 
Published: October 2023

Galileo’s principle has no explanation on its own. Instead, it finds its explanation in the principle of equivalence proposed by Einstein. The principle of equivalence depends on Rock the psychologist’s work on induced self-motion and induced self-rest. An example of the principle of equivalence discussed by Einstein is the equivalence of: 1) a human observer in a chest in outer space that to an outside human observer is accelerating and 2) the human observer in the chest experiencing himself not moving where he sees freely falling objects of any kind accelerating at the same rate, feeling gravity on his body as he stands on the “floor” of the chest he is in, and is convinced he is at rest in a gravitational field.For the outside observer, the objects of any kind that the observer in the chest sees as accelerating toward him at the same rate are for the outside observer not moving, and the outside observer sees the observer in the chest as accelerating toward the objects. If the observer in the chest did not experience himself at rest, but instead, saw that he was accelerating, he would also see the objects as stationary and that he is accelerating towards all the objects at the same rate. If the observer in the chest sees himself as accelerating, there is no principle of equivalence and thus no theory of general relativity. Thus, it is critical to understand what it means for the human observer in the chest (and also the outside observer) to each perceive themselves at rest. Einstein’s principle of equivalence depends on many perceptual and cognitive factors investigated by Rock and others, but all of which have not been seriously considered by physicists. The general theory of relativity which depends on the principle of equivalence, and the special theory of relativity which provides part of the foundation for the theory of general relativity, depend on these perceptual and cognitive factors and on the relativity of an observer seeing himself at rest or instead in motion.Rock proposed that if a passive human observer moving at a constant speed and in a constant direction would not experience self-initiation of motion or changes in proprioceptive cues (i.e., muscle tonus or vestibular cues) that would result in the observer experiencing motion, manipulating visual input could provide cues that would lead the person to experience motion (induced self-motion). If true, then visual input should also be able to be manipulated that would provide cues that the person was at rest (not moving) (induced self-rest) . These ideas mean that the human observer’s “motion” and “rest” are relative for the observer. For the human observer, there is no underlying absolute space and time in which motion and rest are absolute. Rock provided experimental evidence to support his thesis. Einstein provided the means to extend Rock’s thinking to an observer in an accelerating reference frame which for the observer himself can be seen as an inertial reference frame in a gravitational field in which the observer sees himself at rest.