From Quanta Magazine ( find original story here ).

"Insanity is doing the same thing over and over and expecting dissimilar results."

That witticism—I'll call information technology "Einstein Insanity"—is usually attributed to Albert Einstein. Though the Matthew effect may be operating hither, it is undeniably the sort of clever, memorable ane-liner that Einstein ofttimes tossed off. And I'g happy to give him the credit, because doing then takes u.s.a. in interesting directions.

Beginning of all, notation that what Einstein describes as insanity is, co-ordinate to quantum theory, the way the world actually works. In breakthrough mechanics you can practise the aforementioned affair many times and go different results. Indeed, that is the premise underlying cracking high-energy particle colliders. In those colliders, physicists fustigate together the same particles in precisely the aforementioned way, trillions upon trillions of times. Are they all insane to do so? It would seem they are not, since they have garnered a stupendous diversity of results.

Of course Einstein, famously, did not believe in the inherent unpredictability of the world, maxim "God does not play dice." All the same in playing dice, we deed out Einstein Insanity: We exercise the aforementioned thing over and over—namely, curl the die—and we correctly anticipate unlike results. Is it actually insane to play dice? If then, information technology's a very common form of madness!

We can evade the diagnosis past arguing that in do i never throws the dice in precisely the same way. Very modest changes in the initial conditions can change the results. The underlying thought here is that in situations where we can't predict precisely what's going to happen next, information technology's because there are aspects of the current situation that we haven't taken into account. Like pleas of ignorance can defend many other applications of probability from the allegation of Einstein Insanity to which they are all exposed. If we did take full admission to reality, according to this argument, the results of our actions would never be in dubiousness.

This doctrine, known as determinism, was advocated passionately by the philosopher Baruch Spinoza, whom Einstein considered a corking hero. But for a better perspective, we need to venture even further back in history.

Parmenides was an influential ancient Greek philosopher, admired by Plato (who refers to "father Parmenides" in his dialogue the Sophist). Parmenides advocated the puzzling view that reality is unchanging and indivisible and that all motion is an illusion. Zeno, a student of Parmenides, devised four famous paradoxes to illustrate the logical difficulties in the very concept of move. Translated into modern terms, Zeno's arrow paradox runs every bit follows:

  1. If you know where an pointer is, you know everything about its physical country.
  2. Therefore a (hypothetically) moving pointer has the aforementioned physical state as a stationary arrow in the aforementioned position.
  3. The electric current concrete land of an pointer determines its future concrete state. This is Einstein Sanity—the denial of Einstein Insanity.
  4. Therefore a (hypothetically) moving arrow and a stationary arrow have the same future concrete land.
  5. The arrow does non move.

Followers of Parmenides worked themselves into logical knots and mystic raptures over the rather blatant contradiction between point v and everyday feel.

The foundational accomplishment of classical mechanics is to found that the commencement indicate is faulty. It is fruitful, in that framework, to allow a broader concept of the character of physical reality. To know the state of a system of particles, one must know not only their positions, but too their velocities and their masses. Armed with that information, classical mechanics predicts the organisation'due south future evolution completely. Classical mechanics, given its broader concept of physical reality, is the very model of Einstein Sanity.

With that triumph in mind, let the states return to the apparent Einstein Insanity of quantum physics. Might that difficulty besides hint at an inadequate concept of the state of the earth?

Einstein himself thought and then. He believed that in that location must be hidden aspects of reality, not nevertheless recognized within the conventional formulation of breakthrough theory, which would restore Einstein Sanity. In this view information technology is non so much that God does not play dice, but that the game he's playing does not differ fundamentally from classical die. Information technology appears random, but that'south only because of our ignorance of sure "hidden variables." Roughly: "God plays dice, but he'due south rigged the game."

But as the predictions of conventional quantum theory, free of subconscious variables, have gone from triumph to triumph, the wiggle room where 1 might accommodate such variables has become small and uncomfortable. In 1964, the physicist John Bong identified certain constraints that must apply to any physical theory that is both local—meaning that physical influences don't travel faster than light—and realistic, meaning that the physical properties of a system exist prior to measurement. But decades of experimental tests, including a "loophole-free" test published on the scientific preprint site arxiv.org last month, testify that the world we alive in evades those constraints.

Ironically, conventional quantum mechanics itself involves a vast expansion of physical reality, which may be plenty to avoid Einstein Insanity. The equations of breakthrough dynamics allow physicists to predict the time to come values of the moving ridge function, given its nowadays value. Co-ordinate to the Schrödinger equation, the moving ridge function evolves in a completely predictable way. But in practice we never have access to the total wave function, either now or in the future, so this "predictability" is unattainable. If the wave function provides the ultimate description of reality—a controversial issue!—we must conclude that "God plays a deep yet strictly dominion-based game, which looks similar die to us."

Einstein's dandy friend and intellectual sparring partner Niels Bohr had a nuanced view of truth. Whereas according to Bohr, the opposite of a unproblematic truth is a falsehood, the opposite of a deep truth is some other deep truth. In that spirit, let us introduce the concept of a deep falsehood, whose reverse is besides a deep falsehood. Information technology seems fitting to conclude this essay with an epigram that, paired with the one we started with, gives a nice example:

"Naïveté is doing the same thing over and over, and always expecting the aforementioned effect."

Frank Wilczek was awarded the 2004 Nobel Prize in physics for his piece of work on the theory of the strong force. His most recent book is A Beautiful Question: Finding Nature's Deep Design. Wilczek is the Herman Feshbach Professor of Physics at the Massachusetts Institute of Technology.

Reprinted with permission from Quanta Magazine, an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of scientific discipline by covering research developments and trends in mathematics and the concrete and life sciences.