D O C U M E N T S 2 3 0 , 2 3 1 2 3 9 230. To Hans Reichenbach [Berlin,] 20 March 1926 Dear Mr. Reichenbach, I haven’t done anything more for you because I was told there is a quite certain prospect of your being appointed in Prague. Now I have written to the Amerika- Institut[1] and am going to look around in America as soon as I have received word. I believe that there would be a sphere there for you it would perhaps be nicer in Prague, albeit the vibrancy there would be meager. Couldn’t I perhaps do some- thing for you in Prague? You are entirely right about the Γ-criticism.[2] Now I have given up all hope of coming further along this formal path. It doesn’t work without any really new idea.[3] I am sending you the celebratory Lorentz issue, in which my notice is published.[4] Unfortunately, I have not yet been able to read your paper on causal structure.[5] The statistical blurring[6] of causality is logically all right, but inwardly I am bristling. Kind regards, your A. Einstein 231. To Emil Rupp[1] [Berlin,] 20 March 1926 Dear Colleague, I am attaching a note for you,[2] prompted by your interesting article in the Annalen.[3] It ought to be relatively easy for you to perform this fundamental ex- periment. In your experiment, one thing, about which I would like to have your view, remained unclear to me. If light from the canal ray beam K