Princeton, 13 July 1952

The subjective appreciation of time is obligatorily 'eliminated from the conceptual construction of the objective universe'.

Besso has spoken of a 'forced current of time', but Einstein objects to the notion that time is 'forced' to move in a single direction: 'The word "forced" indicates a subjective experience, the weight of consciousness, and the order in which they appear inevitably appear to us (on the basis of memory). The "Now" plays a dominant role in this', but this is obligatorily 'eliminated from the conceptual construction of the objective universe'. Besso has also spoken of the 'residues of similarly constructed universes': Einstein takes issue in a handwritten footnote with the word 'residue', which 'seems to indicate that you do not take seriously the four-dimensionality of relativity, but consider the present as the only reality. What you describe as universes are in the language of physics "spatial sections", to which the theory of relativity (beginning with the special theory) denies objective reality'. The remainder of Besso's questions leave Einstein perplexed: he understands that Besso is describing a temporal disposition of spatial sections, and reflecting on how we pass from our personal experience to an objective understanding of these; thereafter when Besso moves on to a 'projection of the ray of the past' and similar questions, he no longer follows him: 'In fact, it is one of your particularities that you never clearly formulate the problem that you want to clear up. You do not sufficiently acknowledge the chasm between the "I" and the "You" ...'.