Einstein's first steps toward general relativity: \textit{Gedanken} experiments and axiomatics. (Q1975519)

The author attempts to reconstruct Einstein's mental path from the special relativity paper of 1905 through the invited review paper of 1907 in Johannes Stark's \textit{Jahrbuch der Radiatioactivität und Elektronik} to the general relativity paper of 1915. A falling human is thought to experience no gravity as an observer: acceleration equates to gravitation; an hypothesis that mass is equivalent to energy becomes an axiom or unprovable principle; recollections written down a decade or two after the event are used to reconstruct a train of thought. The author assembles from evidence all the ideas running around in Einstein's head, his purposes, his attempts to incorporate gravitation into relativity, and presents his picture of scientific creativity in action based on cognitive science and the role of visual imagery so strong in Einstein's thought patterns.