Letter from Prof. Albert Einstein Regarding the Formalization of the "Third Stage of the Theory of Relativity." ...

Letter from Prof. Albert Einstein Regarding the Formalization of the "Third Stage of the Theory of Relativity." Signed Autograph. 1928

Letter written and signed by Prof. Albert Einstein regarding the "Unified Field Theory of Gravitational Force and Electromagnetism" to his colleague, mathematician Prof. Herman Muntz. With a scientific comment that Einstein jotted down on the original envelope. 10.12.1928.

Specifications: [1] ink on paper. Signed autograph. 27.5x22 cm. German. [25] lines written in ink by Einstein. In addition, [1] envelope addressed by Einstein to Dr. Herman Muntz. 12.5x15 cm. Einstein added [3] lines in his hand to the envelope. The envelope bears a stamp with the word "Berlin."

Unique features: This letter is a unique, significant historic document that reveals Einstein's thought process and his methods at that point in time, regarding his Theory of Relativity, one of the most significant scientific achievements of the 20th century.
It was written during one of the most exciting, feverish periods of Einstein's scientific career. About a month after writing this letter, he published his article regarding the Unified Field Theory [UFT], in which he discloses the final stages of the development of this theory, and it reveals critical stages in the solution that he presents. This theory tried to achieve one unified formula that would unite the electromagnetic and gravitational fields and present them as different manifestations of a single universal force. In this letter, Einstein reaches conclusions that will later stand at the base of his theory regarding the mathematical format of the electromagnetic equations. Einstein gives a more specific formulation after he already finished the letter, on its envelope!
The new approach to the theory that Einstein wrote in the three lines on the envelope, a short time after writing and sealing the letter, discloses Einstein's genius creative mind. It also reveals the feverish pace, within a few hours - or at most a day - during which Einstein could sharpen his basic approach to a very complicated problem, while making a very quick turn about. Einstein's letter and his statements during this period indicate that he considered the Unified Field Theory a central part of the Theory of Relativity and viewed it as the third stage in its development, following the Special Theory of Relativity and the General Theory of Relativity. During the last forty years of his life, Einstein was obsessed with the "unitary tendency" and his search for the field equation for the total field. This letter discloses an aspect of this obsession, in a moment of perhaps Einstein's most important period of his unification program. 
On the very same day that he wrote this letter, Einstein submitted a paper to the editor of the "Festschrift," so it can be used to shed light on Einstein's philosophical drive and mood at the time. He states that phenomena according to the UFT theory would take on such a structure "that even G-d Himself could not have arranged those connections in any other way than that which factually exists, any more that it would be in His power to make the number 4 into a prime number." 
In his book Thematic Origins of Scientific Thought, Kepler to Einstein (1973), Mr. Gerald Holton points to the philosophical kinship of Einstein's position with that of Johannes Kepler in his Mysterium Cosmographicum where he announced that he wanted to discover the number, positions and motions of the planets, "why they are as they are, and not otherwise," and who wrote to Herwart in April 1559, that with regard to numbers and quantity, "Our knowledge is the same kind as G-d's, at least insofar as we can understand something of it in this mortal life."

Background: To demonstrate the significance of this letter, we must note Einstein's article of 3.2.1929, in which he presents his new discoveries. There he states that his Theory of Relativity reached its third stage over the last six months. 
In 1928, Einstein suffered a temporary physical collapse due to an enlarged heart and he had to stay in bed for four months. He fully recuperated but remained weakened for a year. At the end of May 1928, he wrote to his friend Zagger: "In the tranquility of my sickness I have laid a wonderful egg in the area of general relativity. Whether the bird that will hatch from it will be vital and long-lived only G-d knows." The "egg" that hatched was Einstein's important paper on UFT, and it was the result of six months of hard work. 
In addition, in an interview with the "Daily Chronicle" on January 26th, Einstein stated: "Now, but only now, we know that the force which moves electrons in their ellipses about the nuclei of atoms is the same force which moves our earth in its annual course about the sun, and it is the same force which brings us the rays of light and heat which make life possible upon our planet."

Prof. Herman Muntz [1884-1956] was a Jewish-German mathematician who was Einstein's colleague in 1927-1929. He helped Einstein with the complex mathematical equations related to the physical theories he developed.

Condition: Very fine. Fold marks. Tear on the side of the envelope, not affecting text. This lot includes a certificate of authenticity.