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The scientific research is based on the correspondence between the reality of nature, acquired through observations, and a representation of this reality, formulated by a theory in the language of mathematics. When all the consequences of a theory are verified experimentally, this approach is validated. This approach, which was applied for nearly four centuries, has allowed us to build a coherent set of knowledge. But these advances were achieved thanks to the human intelligence that, in spite of everything, preserved their beliefs and biases, which can affect the progress of science even among the most prodigious minds.
The first error
In his masterwork the general theory of relativity, Einstein wrote the equation that describes the evolution of the universe as a function of time. In place of the large sphere of constant volume, through which is slid the stars, as it was believed until then, the solution of this equation shows a universe unstable.
At the beginning of the TWENTIETH century, the world lived with the idea well-rooted in a static universe in which the movement of the stars was repeated without a break. It is likely due to the teachings of Aristotle, which stated that the sky was unchanging, in contrast with the perishable nature of the Earth.
This belief led to a historical anomaly: in the year 1054, the chinese had noticed a new light in the sky that it is not mentioned in any european document, and that you could see the full light of day for several weeks. It was a supernova , that is to say, a dying star, whose remains can still be seen in the Crab nebula. The dominant thought in Europe prevented to accept a phenomenon so contrary to the idea of a sky immutable. A supernova is a very rare event, that can only be observed at a glance once every hundred years –the last was in 1987–. So Aristotle was almost right when he stated that the sky was unchanging, at least at the scale of a human life.
in order To not contradict the idea of a static universe, Einstein introduced in his equations a cosmological constant that freeze the state of the universe. The intuition failed her: in 1929, when Hubble showed that the universe was expanding, Einstein admitted to having made “his greatest error”.
randomness in quantum
at The same time that the theory of relativity, is developed the quantum mechanics , which describes the physics of the infinitely small. Einstein had an outstanding contribution in this area, in 1905, with his interpretation of the photoelectric effect as a collision between electrons and photons, that is to say, between particles infinitesimal carriers of energy. In other words, the light, is described traditionally as a wave, behaves as a stream of particles. It was for this advancement, and not for the general theory of relativity, for which Einstein was awarded the Nobel Prize in 1921.
But, despite this vital contribution, is he sinned yet more, to reject the most important lesson of quantum mechanics, which states that the world of particles is not subject to the strict determinism of classical physics. The quantum world is probabilistic, which implies that we are only able to predict a probability of occurrence among a set of possible events.
The obsession of Einstein reveals again the influence of the Greek philosophy. Plato taught that the thought should be ideal, free of the contingencies of reality, which is a noble idea, but far removed from the precepts of science. As well as the knowledge requires a perfect match with all of the facts predicted, the belief is based on a likelihood the result of observations partial. The own Einstein was convinced that the pure thought was able to encompass all of reality, but the randomness of quantum contradicts the hypothesis.
In practice, that randomness is not full, since it is governed by the principle of uncertainty of Heisenberg. This principle imposes a determinism collective sets of particles: an electron by itself is free, since no one can calculate its trajectory when passing through a slit, but a million electrons show a diffraction pattern of which shows dark fringes and bright that you can predict.
the Result of the experiment of interference of Young: with the arrival of progressive of electrons (8 electrons in the image, 270 in the image b 2000 image c, and 60,000 in the image (d) are formed the vertical stripes that constitute the so-called interference pattern. Dr Tonomura/Wikimedia, CC BY-SA
Einstein did not want to admit that indeterminism elementary and summed it up in a verdict provocative: “God does not play dice with the universe”. Proposed the existence of hidden variables , of magnitudes by discover beyond the mass, charge and spin, which physicists use to describe the particles. But the experience gave him no reason. There is that assume the existence of a reality that transcends our understanding, that we may not know everything in the world of the infinitely small.
The vagaries incidental to the imagination
In the process of the scientific method there is a step that is not completely objective and is the one that leads to the conceptualization of a theory. Einstein gives an illustrious example of the same with their mental experiments. So he said: “imagination is more important than knowledge.” In fact, from observations, disparate, a physical must imagine an underlying law. Sometimes, there is a choice between several theoretical models possible, at which time the logic takes the control.
“intelligence has nothing to search: it has to clear the land. So it is only useful for tasks as menial” (Simone Weil, gravity and grace).
therefore, the progress of ideas is nurtured by what we call the intuition . It is a kind of leap in knowledge, which goes beyond the pure rationality. The border between the objective and the subjective ceases to be at all watertight. The thoughts are born in the neurons under the effect of electromagnetic pulses and, between them, some are particularly fecund, as if to provoke a short circuit between cells, the work of chance.
But these intuitions, these “flowers” of the human spirit, are not the same for all people. While the brain of Einstein devised E = mc2 , the Proust created a metaphor that is admirable. The intuition is manifested randomly, but this randomness is shaped by experience, culture and knowledge of each person.
benefits of gambling
it should be No surprise that there is a reality that surpasses our own intelligence. Without the random, we are guided by our instincts, our habits, everything that makes us predictable. Our actions are confined almost exclusively in the first level of reality, with their concerns ordinary and chores required. But there is another level at which the random’s manifest is the sign of identity.
“Never any administrative effort or school will replace the miracles of chance to be great men” (Honoré de Balzac, cousin Pons).
Einstein is an example of a free-spirit, and creator, which retains, however, their prejudices. Your first “error” can be summed up in the phrase “I refuse to believe that the universe had a beginning.” But the experience proved that he was mistaken. Your sentence about God playing dice wants to say: “I refuse to believe in chance”. However, quantum mechanics implies a randomness forced. One might ask if he had believed in God in a world without random, which would reduce a lot of our freedom to see us confined to an absolute determinism. Einstein is held in its rejection, because, for him, the human brain must be able to understand the universe. With much more modesty, Heisenberg responds that the physical is limited to describe the reactions of nature in some circumstances.
The quantum theory shows that we cannot achieve a full understanding of everything that surrounds us. In compensation, it offers us the chance with their frustrations and dangers, but also with its benefits.
“man only escapes from the laws of this world for the space of a spark. Moments of stopping, of contemplation, of intuition pure […] In moments and is capable of the supernatural” (Simone Weil, gravity and grace).
The legendary physicist is the perfect example of being imaginative par excellence. His denial of the chance, therefore, represents a paradox, because it is what makes possible the intuition, the germ of the creation process, both for the sciences as for the arts.
François Vannucci. Professor emeritus, researcher in Particle Physics, a specialist in Neutrinos, University of Paris.
This article was originally published in “The Conversation”.