**On the theory of relativity (book)** . It is a work published by ALBERT EINSTEIN (1879-1955) before he definitively established the famous field equations of general relativity. It tries to give an idea as exact as possible of the theory of relativity, thinking of those who, without mastering the mathematical apparatus of __theoretical physics__ , have an interest in the theory from the general scientific or philosophical point of view. This work includes, as an appendix, a simple derivation of the Lorentz transformation and an exposition of Minkowski’s four-dimensional formulation.

Summary

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- 1 argument
- 2 To the reader
- 3 Introduction
- 4 Contents
- 5 Sources

Argument

The author has made every effort to highlight the main ideas with maximum clarity and simplicity, generally respecting the order and context in which they really emerged. For the sake of clarity, it seemed inevitable to repeat myself often, without paying the slightest attention to expository elegance; I stubbornly adhered to the precept of the brilliant theorist L. Boltzmann, to leave elegance for tailors and shoemakers. The difficulties that lie in the theory itself I think I have not hidden from the reader, while the empirical physical bases of the theory have been deliberately treated with some negligence, so that the reader away from physics does not happen what the walker, who the trees do not let him see the forest. I hope the little book brings more than a few hours of joyous entertainment.

The reader

Surely you too, dear reader, made a childhood acquaintance with the superb building of the Geometry of Euclid and remember, perhaps with more respect than love, the imposing construction through whose high stairs you were walked for hours without count by the meticulous teachers of the subject . And surely, by virtue of that your past, you would punish with contempt anyone who declared false even the most hidden theorem of this science. But it is very possible that this feeling of proud security left you immediately if someone asked you: “What do you understand when you affirm that these theorems are true?” Let us pause for a while on this question.

Introduction

Geometry starts from certain basic concepts, such as plane, point, line, to which we are able to associate more or less clear representations, as well as certain simple propositions (axioms) that, based on those representations, we are inclined to take for “true”. All other theorems are then referred to those axioms (that is, they are proved) on the basis of a logical method whose justification we feel compelled to recognize. A theorem is correct, or “true,” when it is derived from axioms by that recognized method. The question of the “truth” of the different geometric theorems refers, then, to that of the “truth” of the axioms. However, it has been known for a long time that this last question is not only not solvable with the methods of Geometry, it doesn’t even make sense in itself. You cannot ask whether or not it is true that only one line passes through two points. It can only be said that Euclidean geometry deals with figures that it calls “straight” and to which it assigns the property of being unambiguously determined by two of its points. The concept of “true” does not apply to the propositions of pure Geometry, because with the word “true” we usually always designate, ultimately, the coincidence with a “real” object; Geometry, however, is not concerned with the relationship of its concepts to objects of experience, but only with the logical relationship between these concepts. It can only be said that Euclidean geometry deals with figures that it calls “straight” and to which it assigns the property of being unambiguously determined by two of its points. The concept of “true” does not apply to the propositions of pure Geometry, because with the word “true” we usually always designate, ultimately, the coincidence with a “real” object; Geometry, however, is not concerned with the relationship of its concepts to objects of experience, but only with the logical relationship between these concepts. It can only be said that Euclidean geometry deals with figures that it calls “straight” and to which it assigns the property of being unambiguously determined by two of its points. The concept of “true” does not apply to the propositions of pure Geometry, because with the word “true” we usually always designate, ultimately, the coincidence with a “real” object; Geometry, however, is not concerned with the relationship of its concepts to the objects of experience, but only with the logical relationship between these concepts.

Content

- On the theory of special relativity.
- On the theory of general relativity.
- Considerations about the universe as an appendix whole.