The question "What is real?" can be traced back to the shadows in Plato's cave. Two thousand years later, Rene Descartes lacked knowledge about arguing against an evil deceiver feeding us the illusion of sensation. Descartes' epistemological concept later led to various theories of sensory experiences. The concept of "illusionism", proposing that even the very conscious experience we have is an illusion, is not only a red-pill scenario found in the 1999 science fiction movie "The Matrix" but is also a philosophical concept promoted by modern tinkers, most prominently by Daniel Dennett. Reflection upon a possible simulation and our perceived reality was beautifully visualized in "The Matrix", bringing the old ideas of Descartes to coffee houses around the world. Irish philosopher Bishop Berkeley was the father of what was later coined as "subjective idealism", basically stating that "what you perceive is real". With the advent of quantum technologies based on the control of individual fundamental particles, the question of whether our universe is a simulation isn't just intriguing. Our ever-advancing understanding of fundamental physical processes will likely lead us to build quantum computers utilizing quantum effects for simulating nature quantum-mechanically in all complexity, as famously envisioned by Richard Feynman. In this article, we outline constraints on the limits of computability and predictability in/of the universe, which we then use to design experiments allowing for first conclusions as to whether we participate in a simulation chain. Eventually, in a simulation in which the computer simulating a universe is governed by the same physical laws as the simulation, the exhaustion of computational resources will halt all simulations down the simulation chain unless an external programmer intervenes, which we may be able to observe.
The question "What is real?" can be traced back to the shadows in Plato's cave. Two thousand years later, Rene Descartes lacked knowledge about arguing against an evil deceiver feeding us the illusion of sensation. Descartes' epistemological concept later led to various theories of sensory experiences. The concept of "illusionism", proposing that even the very conscious experience we have is an illusion, is not only a red-pill scenario found in the 1999 science fiction movie "The Matrix" but is also a philosophical concept promoted by modern tinkers, most prominently by Daniel Dennett. Reflection upon a possible simulation and our perceived reality was beautifully visualized in "The Matrix", bringing the old ideas of Descartes to coffee houses around the world. Irish philosopher Bishop Berkeley was the father of what was later coined as "subjective idealism", basically stating that "what you perceive is real". With the advent of quantum technologies based on the control of individual fundamental particles, the question of whether our universe is a simulation isn't just intriguing. Our ever-advancing understanding of fundamental physical processes will likely lead us to build quantum computers utilizing quantum effects for simulating nature quantum-mechanically in all complexity, as famously envisioned by Richard Feynman. In this article, we outline constraints on the limits of computability and predictability in/of the universe, which we then use to design experiments allowing for first conclusions as to whether we participate in a simulation chain. Eventually, in a simulation in which the computer simulating a universe is governed by the same physical laws as the simulation, the exhaustion of computational resources will halt all simulations down the simulation chain unless an external programmer intervenes, which we may be able to observe.
Feynman gave in 1982 a keynote speech \textit{Simulating Physics with Computers} (Int. J. Theor. Phys. {\bf 21}, 467 (1982)) in which he talked ``...about the possibility...that the computer will do exactly the same as nature". The motivation was that: ``...the physical world is quantum mechanical, and therefore the proper problem is the simulation of quantum physics". Here I try after more than forty years to answer Feynman's question of whether it is possible to perform exact computer simulations. Many computer simulations are not exact, they contain mean field approximations that disobey the symmetry in the quantum dynamics with Newton's third law, e.g. almost all astrophysical simulations of galaxy systems. After a review of computer simulations and the problems of simulating real systems, I argue that Newton's discrete dynamics, which is used in almost all computer simulations and which is exact in the same sense as Newton's analytic dynamics, is the classical limit path of Feynman's quantum paths. However, the physical world is not known exactly and it is much more complex than any simulated systems, and so far no real systems have been simulated exactly. Hence, more than forty years later, and after hundreds of thousands of computer simulations of the physical system's dynamics the answer to Feynman's question is still negative. But although it is not possible to simulate the dynamics exactly for any real systems, the simulations have been and will be of great use in Natural Science.
It must have been around 1950. I was accompanying Einstein on a walk from The Institute for Advanced Study in Princeton to his home, when he suddenly stopped, turned to me, and asked me if I really believed that the moon exists only if I look at it. The nature of our discussion was not particularly metaphysical. Rather, we were discussing the quantum theory … (Abraham Pais, 1982) There is an old debate in philosophy about whether the world outside our minds exists at all. In the early-seventeenth century, Descartes pioneered the new mechanical and geometrical view of material reality in which every event was determined. But he also believed that we each had a soul and that our will was free. Thus he had to insist that matter and the soul were entirely different: the mind-body split was born. Descartes's critics soon pointed out that a soul confined within the “veil of perception” had no direct evidence that its perceptions were true. Perhaps they were mere illusions or some sort of cinematic film projected by God? Bishop Berkeley went so far as to suggest that there are no bodies outside the mind, and that perceptions were the only reality: “to be is to be perceived”. Samuel Johnson thought this was all twaddle. He famously rebutted Berkeley by kicking a stone, as if to say that its reality was painfully obvious. During the past 30 years, there has been a resurgence of these sorts of questions.
“I refute it thus!” Samuel Johnson famously dismissed Bishop George Berkeley's argument for the unreality of matter by kicking a large stone (Boswell, 1823). In the light of modern physics, however, Johnson's simple reasoning evaporates. Apparently solid matter is revealed, on closer inspection, to be almost all empty space, and the particles of which matter is composed are themselves ghostly patterns of quantum energy, mere excitations of invisible quantum fields, or possibly vibrating loops of string living in a ten-dimensional space–time (Greene, 1999). The history of physics is one of successive abstractions from daily experience and common sense, into a counterintuitive realm of mathematical forms and relationships, with a link to the stark sense data of human observation that is long and often tortuous. Yet at the end of the day, science is empirical, and our finest theories must be grounded, somehow, “in reality.” But where is reality? Is it in acts of observation of the world made by human and possibly non-human observers? In records stored in computer or laboratory notebooks? In some objective world “out there”? Or in a more abstract location? The ground of reality When a physicist performs an experiment, he or she interrogates nature and receives a response that, ultimately, is in the form of discrete bits of information (think of “yes” or “no” binary answers to specific questions), the discreteness implied by the underlying quantum nature of the universe (Zeilinger, 2004). Does reality then lie in the string of bits that come back from the set of all observations and experiments – a dry sequence of ones and zeros? Do these observations merely transfer really-existing bits of information from an external world reality to the minds of observers, or are the bits of information created by the very act of observation/experiment? And – the question to which this entire discussion is directed – are bits of “classical” information the only sort of information that count in the reality game, or does an altogether different form of information underpin reality? In short, where is the ontological ground on which our impression of a really-existing universe rests?
Perceived reality is an illusion.We exist in a universal quantum geometrical system that operates because of consciousness, not in isolation from it.Consciousness is not a byproduct of matter.Matter is arguably a by-product of consciousness, as matter is essentially structurally indistinct and far less tangible than what classical, materialist science has led us to believe.Consciousness stimulates excitations and changes in the quantum field; the omnipresent energy baseline field of the universe.This facilitates quantum collapse of probability waveforms that existed in super-position prior to this process.Reality is manifested initially via sound, and secondarily, via light, both of which are fundamentally quantum information data streams that encode holographic, atomic/quantum field geometrical constructs.These encoded quantum/sound/light geometrical formations, are essentially, reality.The classical physical world that we perceive and experience, and the nebulous, nonlinear, and exceptional nature of quantum mechanics, are potentially irreconcilable.Arguably, the only way this is not the case, is if an intermediary processing modality of physics can be found, one that bridges the diametrically opposed features of classical and quantum physics by incorporating and embodying, to varying extents, aspects from both.This research offers an appellation and classification for this third discipline: synthesist mechanics.If synthesist mechanics can be discovered, as our technological measuring capabilities continue to improve, which may render such a discovery possible, the inherent reality of both our perceived, classical reality, and the mechanics of quantum physics, will be affirmed.However, if synthesist mechanics cannot be found, as has proved to be the case thus far, we must accept the logical, deductive revelation this will pose, that ultimately, our perceived reality is nothing more than an interpretative illusion; a cognitive, translational impression that life subconsciously provides itself with in order to foster reflective, spatiotemporal, geometry-based interactions and experiences.This research confirms that we live in a self-rendering, generative illusion, which exists so that individualised shards of consciousness may interact with others.Ultimately, perceived reality is an illusion derived from the constant quantum interpretations that are made by consciousness via the quantum field.This process provides the unified consciousness behind reality with opportunities to experience, acknowledge, actualise, remove, or refine all possible variances of itself.Existence is the quantum dance consciousness performs in the darkness so that it may illuminate itself.
Abstract I argue for an approach to the Foundations of Physics that puts the question in the title center stage, rather than asking “what is the case in the world?”. This approach, algorithmic idealism, attempts to give a mathematically rigorous in-principle -answer to this question both in the usual empirical regime of physics and in some more exotic regimes within cosmology, philosophy, and science fiction (but soon perhaps real) technology. I begin by arguing that quantum theory, in its actual practice and in some interpretations, should be understood as telling an agent what they should expect to observe next (rather than what is the case), and that the difficulty of answering this former question from the usual “external” perspective is at the heart of persistent enigmas such as the Boltzmann brain problem, extended Wigner’s friend scenarios, Parfit’s teletransportation paradox, or our understanding of the simulation hypothesis. Algorithmic idealism is a conceptual framework, based on two postulates that admit several possible mathematical formalizations, cast in the language of algorithmic information theory. Here I give a non-technical description of this view and show how it dissolves the aforementioned enigmas: for example, it claims that you should never bet on being a Boltzmann brain regardless of how many there are, that shutting down computer simulations does not generally terminate its inhabitants, and it predicts the apparent embedding into an objective external world as an approximate description.
Can Reality be simulated by a huge Quantum Computer? Do we believe that Reality is made of something more than interacting quantum systems? The idea that the whole Physics is ultimately a quantum computation—a strong quantum version of the Church-Turing hypothesis well synthesized by the Wheeler’s coinage It from bit—is very appealing. It is theoretically very parsimonious: an Occam razor’s quality-guaranteed description of the world. But, if this is the case, then we need to understand the entire Physics as emergent from the quantum computation. Here I will make a short exploration on how this may come about. Ask a physicist what does he thinks the world is made of. Very likely the first impetuous answer will be: it is made of particles! But, at a second thought the answer will be: it is a Quantum Field. Particles are just states or the Field: they can be created and annihilated. We have indeed a beautiful Grand Unified Field Theory, and we are looking forward to see the Higg’s boson at the LHC. But what is the Quantum Field made of? Ultimately, it is made of quantum systems that are interacting, each system located at a different position in space. Things may be indeed more complicated than that, because the field is a continuum. But is Reality actually continuous? We don ’ t know: but it looks easier to think to Reality as a continuum. Now, suppose that this is not the case, namely Reality is ultimately discrete, and the continuum is only a mathematical fiction. Then, what else is out there more than interacting quantum