Albert Einstein was born in 1879 into a German Jewish family who moved from Ulm (Wurttemberg) to Munich when he was one year old. His mother, Pauline Koch, always was very supportive; she loved literature and music. His father Hermann was a jovial, hopeful man, but not very successful with his small business. Einstein later said he was “extremely friendly, mild and wise.”
In his first years, Albert’s brain had a peculiar way of functioning: it was only at the age of 9 that he could speak fluently; moreover he often took a long time before answering. It has been suggested that he had a form of dyslexia. He had difficulties at school, and when his father asked his headmaster what profession his son should pursue, the answer was: “It does not matter, he’ll never make a success of anything.”
Einstein’s family was not Jewish observant, hence Albert was sent to the Catholic elementary school which was much closer than the Jewish school. However at that time in Munich most people were practicing Catholic, so he was confronted with different dogmas which he and his family considered as fantasy and superstition.
Albert then followed the Gymnasium where he hated the Prussian discipline and “the methods of fear, force, artificial authority which produce servile helots and destroy the healthy feelings….” For Albert, this was a permanent and violent attack against his liberty of thinking, but as he had a strong character, these methods had opposite results: he rejected the dominant beliefs, developed a radically inquiring attitude and worked on his own.
Albert’s passion for physics came quite soon, about at the age of 12 when he realized from popular scientific books that most of the stories in the bible couldn’t be true. This was a big deception for him, which had two important consequences: again a rejection of all authorities, and a search for something else to fill the vacuum, following in this respect the Jewish tradition “obsessed for centuries by a concept of order and harmony in the universal design” (A. Eban). Einstein later wrote: “I want to know how God created this world…I want to know His thoughts, the rest are details.” Einstein also said: “I believe in Spinoza’s God who reveals himself in the harmony of all that exists…”
Coming back to the time when Albert was 15, his family moved to Milan after his father got bankrupt again, and was rescued by his family-in-law. Albert was left alone in Munich to finish the Gymnasium, but he was soon expelled: “your presence in the class is disruptive and affects the other students.” Albert was then very happy in Northern Italy where he found the people highly civilized and educated; he also appreciated the art and the freedom of Italy. Furthermore, he rejected his German citizenship, preferring to be stateless. His parents were despaired as he had no diploma, no possibility to enter university; but luckily, there existed an engineering school, and even the best one in central Europe except Germany, which did not require any diploma but selected its students through a difficult entering exam: Polytechnic Zurich! Egged on by his parents, Albert tried this exam at the age of 16, meaning 2 years in advance, and got an exceptional high mark in maths but miserable ones in other subjects, which induced the Director of Polytechnic to give him the chance to enter the following year after studying in a Swiss school in order to catch up in the subjects where his marks were too low. Albert very much appreciated this Swiss institution where the climate was friendly; he loved Switzerland and several years later, he received the Swiss citizenship. Much later in his life, he said Switzerland was the country where people are “by and large more humane than the other people among whom I had lived.”
In Polytechnic, Albert was not at ease: the courses were engineering oriented whereas he was interested and even passionate with theoretical physics. In particular, Maxwell theory of electromagnetism was not taught, but Albert again worked on his own, learnt it and he later said it was “the most fascinating subject”. Besides, he often skipped courses which didn’t interest him, all of which resulted in the fact that even though he was awarded the diploma, his teachers did not like him: his main professor said: “he is someone intelligent but to whom one can’t tell anything.” His professor of mathematics, Herman Minkowski who later became famous for his important enhancements of the theory of Relativity, remembered Einstein as “a lazy dog, who never bothered about mathematics at all.”
Consequently after Polytechnic, Einstein did not succeed in embracing the academic career he contemplated; and it is after some difficulties that he found a position in the Swiss Patent Office as a preliminary examiner of patent applications. Nevertheless he was pleased to have enough spare time for his scientific research, which he carried out together with a small group of friends, in particular M. Besso, who shared his passion and remained his friends during his whole life. He later said that his position in the patent office had some positive aspects: he learnt how to express himself, and he was not induced to publish many articles on minor subjects as often academic researchers do.
It thus appears that from his early age, Einstein was induced to challenge the dominant beliefs, hence it is understandable that when addressing the problems of electromagnetism, he chose to listen to the heretical voice of Ernst Mach (cf. precursors of Relativity). Einstein spent time since he was 16 wondering what if someone could go at the speed of light and follow a light wave: he should see “a spatially oscillatory field at rest” (his own words), but this was in contradiction with Maxwell equations. When he realized that with a new speeds composition law resulting from a complete revision of our notions of time and distance, such scenario with an observer going at light speed becomes impossible, he knew that he got the solution: time and distance are not absolute but follow the Lorentz transformation when changing frame. Moreover, this new coordinate’s transformation rule rendered Maxwell’s equations compliant with the principle of Relativity. For Einstein, the absolute character of time and distance was just another false dominant belief. Besides, if the new speeds composition law is an “affront to the common sense”, Einstein answered that we should recognize that our common sense is built on experience where all speeds are very far from the speed of light, so that no one can have any idea of what it is like at such speed.
Some other aspects of Einstein’s personality are worth mentioning: We mentioned Einstein always was a determined pacifist; even when he was in Berlin during World War 1, he took very courageous pacifist positions unlike most scientists who turned their activities towards the development of new weapons.
Einstein also was a Zionist and supported the creation of a state for the Jewish people in his historical land. He was offered the presidency of Israel, an honorific function according to the constitution of this State, but he declined, explaining that he has “been dealing with the world of objects and that he has neither the ability nor the experience necessary to deal with human beings and to carry official functions”. He remained attached though to the Jewish tradition: “The pursuit of knowledge for its own sake, an almost fanatic love of justice, and the desire for personal independence, these are the features of the Jewish tradition which make me thank my stars that I belong to it”.
Regarding his beliefs, Einstein said: “True scientific thought is not possible without faith in the inner harmony of our universe, and from this axiom I developed my theory of relativity”. However his beliefs did not play a favorable role regarding Quantum Mechanics: after having taken a leading role in the Quantum Mechanics revolution, Einstein was reluctant to admit the probabilistic nature of fundamental physical laws, and had this famous word: “God does not play dice with the universe”; to which N. Bohr answered: ”Einstein, would you stop telling God what to do.”
When he was asked whom his genius came from, he answered: “I have no particular talent, I am merely extremely inquisitive.” Besides, some of his American colleagues were amazed at his sense of perseverance which they attributed to his German education; but his German education did go as far as his dressing code as he often skipped wearing socks…
Einstein had strong independence needs: he said for instance in 1954: “If I would be a young man again and had to decide how to make my living, I would not try to become a scientist or scholar or teacher. I would rather choose to be a plumber in the hope to find that modest degree of independence still available under present circumstances.” However, his passion for theoretical physics never abandoned him until his last day.
He was a very good violinist and loved music; his elder son said: “Whenever he felt that he had come to the end of the road or into a difficult situation in his work, he would take refuge in music, and that would usually resolve all his difficulties.”
In 1905, before Einstein published his famous articles, the extremely brilliant French mathematician Henri Poincaré found the famous mathematical formula which is the key of Special Relativity, and which he elegantly named: “the Lorentz transform”.
Henri Poincaré, 1854 – 1912, is considered as one of the last great universal scientists and philosopher, mastering in particular all the branches of mathematics of his time.
Henri Poincaré wrote in 1897: “Absolute space, absolute time, even Euclidean geometry, are not conditions to be imposed on mechanics”. He even said in 1904: “Per-haps, we should construct a whole new mechanics, of which we only succeed in catching a glimpse, where, inertia increasing with the velocity, the velocity of light would become an impassable limit.”
All these statements were very prophetical; however H. Poincaré still believed in the existence of the ether even if he recognized it had no effect. His explanations thus were more complex and less physical than the ones of A. Einstein, who rejected the ether existence; moreover, the ether absence naturally extended the laws of Relativity to the whole physics and not only electromagnetism.
H. Poincaré found the Lorentz transform from a mathematical perspective: he searched the transform that would solve the issues of Maxwell equations with regard to the frames equivalence principle, meaning the way that all coordinates of any object are changed from one inertial frame to another one.
Indeed, after the famous Michelson & Morley’s experiment showing that the ether, if it exists, has no impact on light propagation, Maxwell equations raised two major problems: they did not comply with the frames equivalence postulate, and they implied that the speed of light was independent from the velocity of the source which emits it, which was “an affront to the common sense” (an expression by The Times of London).
A previous attempt to solve Maxwell issues was made by the Dutch scientist H. Lorentz (Nobel prize), pursuing an idea of G. Fitzgerald: they stated that the ether produced electromagnetic effects which reduced the lengths of objects along the direction of their motions. This explanation led to the correct length contraction law, which in turn invalidated the classical speeds additivity law, and could explain the invariance of the speed of light. However, the ground of this explanation was false: objects actually are not shrunk since there is no ether, they only appear shrunk from moving observers, as explained Einstein.
Few months before Einstein issued his famous articles, H. Poincaré showed that mathematically the time coordinate must also be changed when changing frame in order to completely solve Maxwell issues with regard to the frames equivalence principle: time must incur a dilatation effect when it is considered by observers who are moving relative to the ether. He thus found his famous formula which he named the “Lorentz transform”, and which is the key of Special Relativity; he elegantly named it so because it combines the Lorentz-Fitzgerald distance contraction effects with the time dilatation effect. However the ether frame was a privileged reference frame giving an absolute time.
His demonstration was mathematical oriented: finding the mathematical group of linear transforms that preserves the quadratic form made of the Lorentzian norm of any space-time interval. It is however Einstein who expressed the correct physical explanation: he rejected the ether existence, there is no privileged frame, and he stated that we must accept light speed invariance as a postulate grounded on Maxwell equations, and therefrom, time and distance are necessarily relative.
Einstein did not mention Poincaré in his famous articles; then H. Poincaré avoided to mention A. Einstein; he recognized Einstein was rapid to accept new ideas. After 1905, H. Poincaré was not very active in developing the theory of Relativity, nor in making it recognized by the scientific community, unlike two other great mathematicians: H. Minkowski and then D. Hilbert who was a precursor of General Relativity.
“The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality.” (The beginning part of his address delivered at the 80th Assembly of German Natural Scientists and Physicians -21 September 1908).
Hermann Minkowski (1864 –1909) was a brilliant German mathematician. As a boy of 18, he won the Paris Prize for Mathematics. 15 years later, he was the professor of Einstein at Polytechnic Zurich, and he then taught at the famous German university of Göttingen. Besides, he was a student and a friend of the great mathematician D. Hilbert.
Minkowski was very interested and impressed by the work of his former student Einstein. He published an article in 1907 where he introduced the fundamental concepts that helped understand and formalize Relativity: we evolve in a 4 dimensional “space-time universe” where the primitive concepts are the “event” and the “proper time”.
Einstein said: “from a happening in the three dimensional space, physics become, as it were, an existence in the four-dimensional”. Moreover, Einstein described Minkowski’s contribution as “the provision of equations in which the natural laws assume mathematical forms in which the time coordinate plays exactly the same role as the three space coordinates”.
These concepts indeed revealed a form of equivalence between time and distance. They are widely used today, and they even seem natural. They are very powerful: they allow for instance to make simpler demonstrations of the famous relation E=mc² as shown in the proposed document which systematically use Minkowski’s concepts. They are also the elementary basic concepts of General Relativity. These concepts are also important from a philosophical perspective as they highlight the close link between time and distance, and it is worth mentioning that a link between time and space has already been noted far ago in history by Aristotle: “in a world without movement, how can we define time ?”
Besides, Minkowski’s contribution in the mathematical tools and methods dedicated to Relativity is immense: he introduced the Minkowski diagrams which are very practical for representing various relativistic scenarios. He also introduced the idea to use complex numbers to represent the time component in the 4 dimensions space-time, which has some interests but not as importantly as his next idea: the introduction of tensors which were rather complex new tools developed by Tullio Levi-Civita.
Einstein initially considered the tensors as a superfluous manifestation of erudition: “The people in Göttingen (mathematicians) sometimes strike me….not as if they wanted to help one formulate something clearly, but as if they wanted only to show us physicists how much brighter they are than we”. However Einstein soon after intensively used the tensors, when he strived hard to develop the General theory of Relativity. It is even questionable if he could have accomplished General Relativity in 1915 if Minkowski had not introduced the tensors in Relativity.
The lecture that Minkowski gave on sept 21, 1908 at the 80th Assembly of German Natural Scientists and Physicians, had an immense impact among the scientific community. Soon after, Relativity was no longer a strange, questionable and half heretic theory, it became a serious and very important one. In 1909, Einstein got his first academic recognition, an honorary doctorate by the university of Geneva, and he was finally accepted as a professor at the university of Zurich.
Unfortunately Minkowski got sick at the end of 1908 and died in early 1909, regretting on his deathbed: “What a pity that I have to die in the age of the relativity’s development.” He was only 44 !
Einstein wrote few weeks before his own death: “…for me personally …H. Lorentz meant more than all others I have met on my life’s journey”.
Hendrik Lorentz (1853 – 1928) was a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect.
According to the biography published by the Nobel Foundation, “It may well be said that Lorentz was regarded by all theoretical physicists as the world’s leading spirit, who completed what was left unfinished by his predecessors and prepared the ground for the fruitful reception of the new ideas based on the quantum theory.” For this he received many honors and distinctions during his life, including —from 1925 to his death in 1928— the role of Chairman of the exclusive International Committee on Intellectual Cooperation.
Lorentz contribution was crucial to the finding of the Lorentz transform, which is the key of Special relativity: after the famous Michelson & Morley’s experiment showing that the ether, if it exists, has no impact on light propagation, Maxwell equations raised two major problems: they did not comply with the frames equivalence postulate, and they implied that the speed of light is independent from the velocity of the source which emits it, which was “an affront to the common sense” (an expression by The Times of London).
It is George Fitzgerald, professor at Dublin’s Trinity College, who first proposed an explanation: he refused to admit that the speed of light is independent from the source which emits it, and suggested that all moving objects were shortened along the direction of their movements. However his explanation did not convince: “I have been rather laughed at for my view” he wrote to Lorentz.
However Lorentz who had been among the first to postulate the existence of the electron, issued the hypothesis that such distance contraction is the result of electromagnetic forces, the moving object having electrical charges evolving in an ether which also has charges. They proposed a mathematical function giving the length contraction which showed that the contractions were too small to be detected for usual speeds, but became extremely important for speeds approaching the light speed, which solved part of the issues of Maxwell equations. Their formula proved to be correct as far as the distances are concerned, but the ground of their explanations was wrong: objects don’t incur real contractions, but it is the way they are seen from moving observers which makes them appear contracted, and this translates the principle of relativity of distance.
Then H. Poincaré issued the correct transform by which Maxwell equations issues are mathematically solved. This transform included the distance contraction of Lorentz-Fitzgerald, hence he elegantly named it the Lorentz transform, but he showed that the time coordinate must also be transformed when changing frame, which meant the relativity of time.
However it is Einstein who expressed the correct physical explanation: he rejected the ether existence and stated that we must accept light speed invariance as a postulate grounded on Maxwell equations, and therefrom, time is necessarily relative, and distance too.
Einstein recognized Mach as a main precursor of Relativity and praised his “greatness in his incorruptible skepticism and independence”
Ernst Waldfried Josef Wenzel MACH (1838 – 1916) was an Austrian physicist and philosopher, noted for his contributions to physics such as the Mach number and the study of shock waves. (Wikipedia).
Before Relativity, scientists were not induced to doubt about physical laws, dominant assumptions and axioms, and in this respect Relativity has introduced an epistemological revolution. But as often, there were some minority voices, and Einstein chose to listen to E. Mach, an heretical philosopher and scientist for whom a statement which cannot be experimentally checked is not acceptable, in particular the absolute character of the time and space of Newton’s universe.
Mach explained that simple concepts are created to describe reality for economical reasons so as to reduce the complexity that our brain has to process; but as science makes progress, these concepts should be challenged and evolve. Besides, what men call “laws of nature are merely summaries of experience provided by their own fallible senses…and the rest doesn’t exist”
Mach also was the first scientist who rejected the existence of the ether after the famous Michelson & Morley (*). The renouncement to the ether was a key factor leading to the Special Theory of Relativity since it made clear the contradictions of Maxwell equations with the frames equivalence principle, and even with the common sense regarding the invariance of light speed; then it is the efforts to solve these contradictions which led to the theory of Relativity.
However Mach remained skeptical about the theory of Relativity, until his death in 1916..
(*) It is worth mentioning that even before Michelson & Morley experiment, there was a Danish scientist, L.V. Lorenz (not to confuse with H. Lorentz) who in 1867 stated:
“The ether hypothesis is not reasonable because it is a medium without substance that was imagined because light is conceived in the same manner as the sound. It must be a medium with extreme elasticity and low density to explain the extremely fast speed of light. It is certainly not scientific to invent a new substance when its existence is not revealed in a better manner”.
H. Lorentz said in 1910: “If there are any missing acknowledgements in Einstein’s work, they belong not to Michelson-Morley, to Lorentz, Fitgerald, or Poincaré but to August Föppl, a German administrator and teacher whose Introduction to Maxwell’s Theory of Electricity was almost certainly studied by Einstein. The famous Relativity paper has similarities in style and arguments with Foppl’s treatment of “relative and absolute motion in space”; and Föppl himself writes of “a deep-going revision of that conception of space which has been impressed upon human thinking in its previous period of development” as presenting “per haps the most important problem of science of our time.”
August Otto Föppl (1854 –1924) was a professor of Technical Mechanics and Graphical Statics at theTechnical University of Munich, Germany. He is credited with introducing the Föppl–Klammer theory and the Föppl–von Kármán equations (large deflection of elastic plates).
His doctoral advisor was Gustav Heinrich Wiedemann and one of Föppl’s first doctoral students was Ludwig Prandtl, his future son-in-law.
In 1894, Föppl wrote a widely read introductory book on Maxwell’s theory of electricity, titled “Theorie der Elektriztät”. Gerald Holtonargues, that some arguments of Föppl concerning electromagnetic induction, had some influence on Albert Einstein’s first paper on special relativity. (source: Wikipedia)
Einstein was only 26 in 1905 when he published his two fundamental articles on Special Relativity in “Annalen der Physik”. He expected harsh criticisms but didn’t receive any reaction until the following year when M. Planck, who was one of the most renowned scientists worldwide, sent him a letter asking for some clarifications. Soon after, Planck was convinced by this revolutionary theory, and contributed to its development together with a small group of scientists. However, this new theory was very slowly accepted mainly because of the lack of experimental confirmations; only the case of the accelerated electrons in cathode ray tubes could be explained by Relativity, but other theories were also proposed for this case. However in 1907-1908 two important events occurred which considerably boosted Relativity acceptance among the scientific community: i) Another important discovery by Einstein: the principle of equivalence, which is the cornerstone of General Relativity; and ii) An important article by H. Minkowski,
Minkowski was a brilliant mathematics professor at the famous Göttingen University: Minkowski introduced fundamental concepts such as the space-time universe, the event, the proper time; these concepts not only structured Special Relativity and facilitated its understanding, but they revealed all the importance of the revolution introduced by Einstein. The next year, Minkowski made an important presentation at the 80th Assembly of German Natural Scientists and Physicians where he prophetically said:” Space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality.”
Minkowski used to be Einstein’s professor of mathematics at Zurich Polytechnic; he was surprised by the very impressive findings of his former student whom he remembered as “a lazy dog, who never bothered about mathematics at all.” Einstein did not leave a great impression at Polytechnic (cf. Who was Albert Einstein), so that he did not succeed in embracing the academic career he contemplated, and accepted a position in the Swiss Patent Office as a preliminary examiner of patent applications. Nevertheless he was pleased to have enough spare time for his scientific research, which he carried out together with a small group of students who shared his passion and who remained his friends during his whole life.
His first academic recognition came in 1909 from Geneva University who granted him an honorary doctorate. However, it is only in the fall of 1909, and after quite some difficulties, that he was nominated as full time Professor “Extraordinary” at the University of Zurich. As a professor, Einstein was rather informal, close to his students, making all efforts so that they understood, and he used to prolong the classes with some of them in a café…
Then in late 1913, the Prussian academy of science made all its best efforts to attract Einstein, and as Plank’s recommendation reads: “All in all, one can say that among the great problems, so abundant in modern physics, there is hardly none for which Einstein has not brought some outstanding contribution.” This was not an easy decision though for Einstein who loved Switzerland and detested Germany (cf. supra). The reason why he accepted this Berlin’s proposal was the fact that it came at a time when he was overwhelmed with very complex research on General Relativity and the Prussian academy offered him the possibility to pursue only his research, while providing him with high level scientific support and good material conditions; besides, he had high respect for Planck.
General Relativity was indeed the next important step after Special Relativity because the phenomenon of gravitation raised a major difficulty with Special Relativity: gravitation was always thought to produce instantaneous distant interactions between massive objects, even over huge distances. Conversely Special Relativity implied that no speed, including distant interactions, could be faster than the speed of light. The principle of equivalence states that locally a gravitational field is equivalent to an accelerated frame, and subsequently a massive object must generate deformations in the space-time universe which are perceived as gravitation effects. The mathematical translation of this principle was very complex, and Einstein succeeded to find the solution in 1915, at approximately the same time as a competing team with the best mathematician of the time, D. Hilbert, striving hard to solve the problem. As a first confirmation, General Relativity was able to explain the trajectory of Mercury which is the sole planet trajectory that did not strictly obey Newton’s laws; but it is during the solar eclipse of 1919 that the great experimental confirmation of General Relativity was achieved with the observation that light rays were deflected in the proximity of the sun. Einstein then became famous worldwide, with a prestige greater than any scientist had ever enjoyed, or suffered in his case, during his life. J.J. Thomson, president of the Royal Society described the General Theory as “one of the greatest, if not the greatest achievements in the history of human thought.”
It may then appear surprising that A. Einstein did not obtain the Nobel Prize either for the discovery of Special Relativity or for General Relativity. He did though in 1921 for the photoelectric effect, rewarding an even more revolutionary article also published in 1905 (hence this year was called his annus mirabilis.) The Nobel committee mentioned his theoretical research, but without quoting the word Relativity. This absence of supreme recognition for the theory of Relativity can be explained, but certainly not justified, by several factors: the Nobel prize was not often attributed to theoretical studies, but privileged experimental works; skepticism among the jury as the Relativity theory was rather complex (especially General Relativity) and not supported by many experimental proofs; no significant applications were foreseen at that time; quantum mechanics was more fashionable among the scientific community; last but not least, anti-Semitism also played a certain role: one member of the consultative committee, Ph. Lenard, publicly called Relativity a “Jewish imposture” !
When the Nazis came in power, A. Einstein suffered from anti-Semitism: despite his Nobel Prize, he was threatened with death and forced to flee from his own country as early as 1933. Besides being born Jewish, the Nazis had another reason to hate him: Einstein always was an active pacifist: “Warfare cannot be humanized, it can only be abolished.” In 1928, he even was president of the human rights league. The Nazis first considered the Relativity theory as an insane produce of the Jewish intellectualism, hence they forbade teaching Relativity. However some important German scientists (e.g. Heisenberg) wanted to continue to use and teach Relativity, but the Nazis did not want to admit that Relativity was discovered by a member of the “inferior race”, so they forbade to mention its discoverer and attributed Special Relativity to an Aryan researcher, Hasenöhrl (and they did the same with N. Bohr). Besides, they fired almost all Jewish researchers and professors, and all this without significant opposition from the scientific and academic communities, nor even from the moral authorities. Ironically, the country that welcomed Einstein became the first to develop the atomic bomb. Einstein warned Roosevelt that an incredibly devastating atomic bomb could be made, and that the Germans might get it (he learnt that a secret uranium project was underway in Germany). However Einstein who still was a pacifist, wrote another letter to the President of the USA asking him not to use the bomb against Japan; he even felt sorry for his first letter. After the war, Einstein campaigned for worldwide nuclear disarmament, and famously said: “I do not know with what weapon World War III will be fought, but World War IV will be fought with sticks and stones.”
Relativity was not only a scientific revolution, it also dramatically changed fundamental scientific methods, as well as the way people consider science.
Before Relativity, physical laws were considered to be absolutely true, in particular the famous Newtonian laws which were valid for falling apples as well as for planets. The previous revolutions made by Copernic and Galileo were considered as victories of science over non-scientific approaches. Moreover, science and its subsequent technological applications had achieved so many great accomplishments since the 17th century, that at the end of the 19th century, it was thought that science could explain everything in a near future. There were some phenomena which did not obey the laws, but they were considered as minor, isolated, and their solutions would likely come soon.
Relativity showed for the first time that even science can be wrong, and that science is a continuous process: it is the best representation of reality mankind makes at a given point of time; there will always be new fields of observations, experiments, and even deeper understanding of existing theories which will lead to new scientific theories and eventually invalidate previous ones; and in such cases, it is some of the axioms and postulates on which these theories were grounded that would be false.
Besides, Relativity has introduced dramatic changes in the roles that intuition and experiments play in the discovery and understanding of physical laws: before Relativity, experiments and intuition played key roles both in the discovery of laws, and in their confirmations. For the first time, intuition played a counterproductive role in Relativity: Relativistic laws are hurting the common sense, but actually it is natural since no one has ever travelled at a speed in the range of the speed of light. For the first time, a postulate, light speed invariance, was not grounded on observations or experiments, but on a better understanding of existing laws.
Since Relativity, scientists are induced to doubt about the axioms, postulates and laws; they elaborate new theories which less rely on experience and more use abstract mathematical formalism. However Einstein emphasized that neither Special nor General Relativity were speculative, he stressed that both theories arose only after observation; but he also later said that that only the theory decides what is observable, and this guideline was very useful in particular for Heisenberg when he found his famous uncertainty law.
It is worth noticing that this epistemological revolution went further than what its author was ready to accept: in particular, after having initiated the quantum mechanics revolution, Einstein was reluctant to accept its evolution and had his famous phrase: “God does not play dice with the universe”, to which N. Bohr answered: ”Einstein, would you stop telling God what to do.”
Experiments and even observations are more and more difficult to realize; confirmations of new theories take a much longer time, as illustrated with the boson of Higgs which is a key element in the Standard Model of particles, and whose confirmation occurred 48 years after it was postulated. Besides, gravitational waves required 100 years for their direct observations.
Since Relativity, postulates become more and more purely speculative. One may then wonder what will distinguish science from other disciplines if neither its postulates nor its results can be confronted with reality for practical reasons. The philosopher K. Popper expressed a red line which distinguishes science from other approaches: a scientific theory must be built on postulates and axioms which are falsifiable, meaning that they are refutable. This criterion is widely admitted among the scientific community, but some voices oppose to it, explaining that there are phenomena which are not accessible to us.
Besides, it appears that the more science has progressed, the more we have discovered the immensity of what we ignore. In particular, we almost ignore 96% of the mass that compose the universe and which doesn’t obey to our existing laws. In their search for new theories, scientists try to find the same simplicity and beauty as with the theory of Relativity. Einstein said: “it is difficult to resist to the charm of Relativity”. It indeed is a beautiful theory in the sense that “its premises are simple but the theory relates to an extended area of applications” (Einstein). Scientists today try to find new theories which unify and even conciliate different existing theories, especially regarding General Relativity and Quantum Mechanics which have important incompatibilities.
It thus appears that the giant steps accomplished by Special and then General Relativity have actually made science come down from its pedestal, a pedestal that was mainly swollen with human pride and credulity. There were however some scientists like Mach and Einstein who were well aware of these human weaknesses; and we can be sure that the “divine curiosity and searcher’s playful need to tinker and think” (Einstein) will continue to make science progress whatever the height of its pedestal.