What is Reality: Definition and 432 Discussions

Reality is the sum or aggregate of all that is real or existent within a system, as opposed to that which is only imaginary. The term is also used to refer to the ontological status of things, indicating their existence. In physical terms, reality is the totality of a system, known and unknown. Philosophical questions about the nature of reality or existence or being are considered under the rubric of ontology, which is a major branch of metaphysics in the Western philosophical tradition. Ontological questions also feature in diverse branches of philosophy, including the philosophy of science, philosophy of religion, philosophy of mathematics, and philosophical logic. These include questions about whether only physical objects are real (i.e., Physicalism), whether reality is fundamentally immaterial (e.g., Idealism), whether hypothetical unobservable entities posited by scientific theories exist, whether God exists, whether numbers and other abstract objects exist, and whether possible worlds exist.

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  1. T

    Decoherence And What happens in reality

    I know that the theoretical decoherence mechanism makes the density mattrix diagonal, but my question is if that happens in real life. I mean, let's take the hidrogen atom (lets work in the QM framework And not in the QFT framework in order to have multiple stationary states) And suppose that...
  2. G

    Has quantum physics proven that thoughts become reality?

    Has quantum physics "proven" that thoughts become reality? This is not a homework assignment. When I go to the homework section, none of the links fit because this is a quantum physics question and it’s neither undergraduate or high school related. If this is not the appropriate forum, please...
  3. O

    How can we measure the reality in quBits?

    How can we measure the "reality" in quBits? Hello All matter is based in information, and quantum computing use quBits, so I was wondering how can we measure the reaility in quBits? A certain solid objet, let's imagine an apple, it has a weight and we can calculate (approximately) the number...
  4. Kawakaze

    Hole in reality? Very strange experience I (we) had

    I am a bit wary about posting this, as I am pretty sure what the response would be if I claimed this was paranormal or some other weird stuff. So before we start, I do not believe in ghosts, I do not follow religion, I am very much a believer in the scientific method. I am not claiming to have...
  5. L

    Lyapunov stability, mathematics vs reality

    Homework Statement I have not been doing Lyapunov for a while and when doing an ordinary Lyapunov problem the other day, I ran into a funny situation. The correct way of doing it: \begin{align} \dot{e} &= \frac{1}{L}(u - R(e + x_{ref})) \\ V(e) &= \frac{1}{2}Le^2 \\ \dot{V} &= Le\dot{e} = Le...
  6. micromass

    Intro Physics The Road to Reality by Penrose

    Author: Roger Penrose Title: The Road to Reality Amazon Link: https://www.amazon.com/dp/0679776311/?tag=pfamazon01-20 Prerequisities: High-school mathematics and physics (in principle) Contents:
  7. M

    Is reality at quantum level just probablilistic?

    Hi. First of all English is not my native language and i am a layperson, so I hope i can explain my self. It is said that reality at the quantum level is probabilistic, not determined. My question is : That is really the case or a probabilistic knowledge is the best we can get as humans...
  8. T

    Electrical Engineering: Build Your Own Virtual Reality

    Hi I just finished high school and want to study electrical engineering in college. My dream is to build a virtual reality machine of my own. Any advice on which area of electrical engineering that I should specialise?
  9. Islam Hassan

    Matter as Excitation of Fields: Model or Reality?

    Are SM particles expected to really be i) simple excitations of their associated fields, ii) particulate matter which happens to be very conveniently (and precisely) modeled as excitations of such fields or iii) we can't judge one way or the other in the present state of our knowledge? If they...
  10. T

    Curvatures in space-time: actual reality or mathematical concept?

    According to GR is space actually supposed to be bending around mass, or is the concept of "curvature" just abstract and purely mathematical idea?
  11. C

    Is objective reality possible under orthodox QM?

    One of the postulates of QM is that the physical state of any system (with any number of constituent particles) corresponds to a Hilbert state vector ψ. So an isolated system that includes an object to be observed, the observing apparatus, and also the human observer himself is also represented...
  12. S

    Quantum entanglement hinting at the nature of reality?

    Citing a recent post from Dr. Chinese, it seems like quantum entanglement experiments are showing something beyond the current standard model. https://www.physicsforums.com/showthread.php?t=637454 If particles can be entangled to other particles that only existed in the past, it seems that it...
  13. Y

    Do Physics majors watch reality tv?

    I know why I don't watch them cause they're crap, and I don't get the point of being famous for having no talent, but just curious if people with scientific backgrounds and higher education enjoy them?
  14. U

    Got the answer, not convinced possible in reality?

    Homework Statement Inertial frame S' moves at a speed of 0.6c with respect to frame S. Further, x = x' = 0 at t = t' = 0. Two events are recorded. In frame S, event 1 occurs at the origin at t = 0 and event 2 occurs on the x-axis at x = 3000m at t = 4*10-6 s. According to observer S', what...
  15. S

    A few questions about gravity, space, and reality in general

    I'm just curious and like thinking about how reality works. I don't now where or if I could find the answers to these questions already written. From what I've seen and read, gravity is cause by space being bent by mass the same way a person standing on a trampoline bends the trampoline. 1...
  16. D

    Is our perception of reality frequency based?

    I found this site via a google search for some key terms I was thinking about. Let me preface by saying I have never taken a physics class, and I am definitely no genius. I formerly was an intelligence analyst in the military working with electronic signals, the concept that I'm now pondering...
  17. tom.stoer

    Unruh effect and lessons regarding reality

    The Unruh effect claims that a quantum state which can be defined as an "empty vacuum state" by an inertial observer will become a "thermal state containing particles" for an observer with constant acceleration a; the temperature observed is T ~ a. In contrast to other oberver dependent...
  18. B

    How can I help make today's developing space technology a reality?

    Hi, I am a college sophomore who is currently headed down a biomedical engineering track. Though I was always somewhat fascinated by space, all of this returning hype about space travel and space mining has really sparked in me the desire to help as much as I can with such proceedings. How...
  19. O

    Wave-particle duality is a correct theory of reality

    Do share your thoughts on this statement.
  20. C

    Reality of the electromagnetic field.

    Hi! I'm currently reading 'An Introduction to the Philosophy of Physics, Marc Lange' where he is arguing about the reality of the electromagnetic field etc. While reading I caught myself in not having the concept of what that makes something real in place. How would one define something as a...
  21. F

    What is the Nature of Reality?

    What is the scientific understanding, and what are peoples' personal opinions about the nature of "reality" Are we living in a reality where everything is basically solid, real, and for the the most part definable by the classical laws of physics, with the quantum world of entangled particles...
  22. J

    Time, Ontology & Platonic Reality vs Material Reality

    I’m not sure in what is the best way approach this topic in-order to stay within the forum guidelines but I hope I’ve done so. From the recent moderator actions, this topic it is too far removed from the philosophy of mathematics to be part of that thread. The basic question is whether existence...
  23. F

    Relating Einstein Tensor to Reality

    Hi, So I have taken a math course dealing with the mathematics behind GR. In it I learnd how to calculate many of the objects that GR deals with such as curvature tensors, geodesics and so on. However, not much physical explination into how these object tie into gravity was discussed (due...
  24. M

    Question: Reality of Quantum State Paper by Pusey, Barrettm & Rudolp

    Question about the "reality of the quantum state" paper by Pusey, Barrettm and Rudolp In the paper I mentioned in the title (on arXiv and supposedly subsequently published in a journal), the authors claim to show that "if a quantum state merely represents information about a system, then...
  25. coktail

    Paradoxes in relativity, and an absolute reality

    This is my first post, so forgive me if I'm posting in the wrong place or violating a rule. I've been doing some reading on relativity, and find myself flummoxed. I understand gravitational time dilation and the principals behind relative velocity time dilation, length contraction, and the...
  26. D

    Limits to pure reason and nature of reality

    Hi all, I have a little out of track question and I was forced to consider this after reading FQXI Essay competition title Is Reality Digital or Analogue and Kant's Critique of Pure reason simultaneously. If I am not wrong, according to Kant, there are limits of pure reason. Is not the...
  27. B

    Is Penrose's Road to Reality the Ultimate Guide to Mastering Physics Math?

    A lot of people keep recommending this book, I have it but I'm a little skeptical about trying it out. I want to do the hard calculations and master them whereas it seems this book just tells you what's out there, it doesn't show you how to master the subject matter. However, it's really hard...
  28. D

    Exploring the Reality of Space-Time Fabric

    I have no idea about it, as my understanding,that Mr.Einstein depicted that what actually happening in space are above on a plane and flat Space-time fabric.Is this telling us that the Earth around is nothing ?What i trying to say is the surrounding of a mass might not exist only a plane of...
  29. W

    What do points on the manifold correspond to in reality?

    In SR the points in Minkowski space correspond to events. I recently read in a GR lecture note that the points on the manifold do NOT correspond to events like in SR (the author even says the points don't have a direct physical meaning). So what do they represent then? And if I continuously...
  30. S

    What is energy in reality, is it PHOTON?

    What is energy in reality, is it PHOTON?? When mass is annihilated, two photons or light is produced. That light has very high(or highest) energy level. As the energy of light depends on it's frequency and wavelength it means that photons are not energy themselves but just energy carrier(gauge...
  31. D

    How can reality be non local and its expression be local.

    what does it mean.
  32. J

    Can reality be defined other than at a point?

    when i think of a particle standing still, i look at it as if it were moving through time, propagating a wake, the wake representing its information propagation. the farther you are from the particle, the longer it will take the wake,travelling at c at its fastest to reach you. because...
  33. F

    Is Beauty an Aspect of Awareness or an Independent Reality?

    I could really do with some consultation here This is mainly to do with reality , being , awareness and meaning for humans. Can we agree reality is one thing and our awareness of what reality is another(- so that is almost a separate reality as we know it)? Im having a mental block at...
  34. M

    Exploring the Reality of Quantum Casino

    On this page : http://www.ipod.org.uk/reality/reality_quantum_casino.asp the guy present a function like this : ψ = A cos(x) then he says according to Euler formula, which is e^ix = cos(x) + i sin(x) : ψ = A e^ix ?? shouldn't the result be instead : ψ + A*i*sin(x) = A cos(x) + A*i*...
  35. T

    Question: Greene's The Hidden Reality : the holographic principle

    Question: Greene's "The Hidden Reality": the holographic principle On pp. 260-261 of "The Hidden Reality" Brian Greene says the following: I puzzled over this for quite awhile and it seems as though Greene, probably inadvertently, phrased this somewhat more decisively than is justified - that...
  36. N

    Preparation to The Road to Reality

    Preparation to "The Road to Reality" Hello everyone, Sorry, I know it's not the right section but I can't post in the "Math & Science Learning Materials" forum. I read really good reviews about Penrose's book "The Road to Reality" and I will probably purchase it, but I also read that the...
  37. U

    The Nature of Infinity in Mathematics and Reality

    Hello all! In the past few months I've stumbled upon an issue that has played games with my mind. I feel I need some help to solve this, as I've tried various other sources and remain without answers. Firstly, I was confronted with a mathematical proof which states that 0.9~ (to infinity)...
  38. A

    If A Kind Soul Would Be Willing - Reality Check

    Hey all, I'm working on a short hard-sci-fi story, and I'm a bit unsure of the foundational accuracy of my work. If anyone is willing, I'd appreciate some critical analysis of some of the appendices, to either make sure I'm kinda on the ball as far as accurately portraying the concepts go, or to...
  39. G

    Exploring Reality Through Bell Tests

    So I've been reading a lot about Bell tests. I have a question that I can't seem to find an answer to. The tests indicate that a photon decides to be horizontally or vertically polarized at the moment of detection. What are they basing this on? To make such a counter-intuitive assumption seems...
  40. bohm2

    The reality of Configuration space

    Someone suggested to me that this stuff may be more appropriate in the QM section (I’m not sure?). I think others on here have brought this up before but I thought I’d post some stuff I’ve come across that may be useful to some as a kind of an introductory reading on the ontology of...
  41. E

    Exploring 4D Space: Physics & Reality

    What is the definition and implications of 4D space? By implications I mean if it existed how will it redefine what we know about physics and reality up to now. (Applications, possibilities, etc)
  42. V

    Does Math always correspond to reality?

    Hello everyone! I got into a debate with a friend about a month back and this question has been racing through my head ever since. Does Math necessarily reflect what's real? He asserted that Math can give you results far-off from what's real. He illustrated his claim like this: Suppose you...
  43. shounakbhatta

    Verifying Time Dilation, Length Contraction & Space-Time Curvature

    Equations or reality... Hello all, I am new to physics forum and very stupidly I don't have a background or formal education in science. I have one simple question: Time dilation, length contraction, curvature of space-time, are they all mathematically deducable through equations or can...
  44. L

    Is Lorentz factor reality true according to the laws of physics?

    Is Lorentz factor reality true according to the laws of physics?? Hi According to the laws of physics, the speed of light is independent of the speed of its source. In the example whereby there are two observers; one in the train moving at high velocity u relative to the other observer on...
  45. StevieTNZ

    Probabilities & Observed Reality

    Hi there, I'm thinking of an experimental set-up that incorporates cameras behind a double-slit screen. The cameras will take a picture if a particle goes through the applicable slit. For me to know which slit it goes through, I need to check the camera to see if its taken a picture. For...
  46. L

    Schools Give me a reality check on grad school admissions?

    Hello, I'm a physics BS and I'm considering pursuing a graduate degree. Ideally I'd like to pursue a PhD in physics, and I'd like a reality check on my chances of admission. What's really putting a damper on things is my mediocre GPA - 2.81 . I'm well aware that this hurts me lots on graduate...
  47. C

    Could black holes form without a singularity?

    This is not a question - more a topic of discussion; as I am not expecting definitive answers. At the center of black holes we stipulate singularities, now I understand that mathematically a singularity does not make sense; infinite density and zero spatial volume being irreconcilable and an...
  48. J

    Is Socrates a Myth or a Reality?

    While the Socrates we know is a paragon and martyr, his biography may not be real. I suspect Plato created a master philosopher for two reasons: 1. To give more weight to himself. Being a student of a heroic certainly boosted his reputation. 2. To give more weight to his ideas. By using...
  49. W

    Medical Uberman Sleep Schedule: Myth or Reality?

    I wasn't quite sure whether to put this here or is skepticism and debunking. Anyway here goes. I was reading the other day about this different way of sleeping that allows one to sleep just two hours a day. It is called the Uberman sleep schedule. Basically, one sleeps every 3-4 hours for 20-30...
  50. B

    Speed of our reality perception…

    I'm really puzzled at our perception of fundamental physical reality… I’ve got it right or all wrong? (I am no scientist, just a curious person, so please bear with me.) Some constants first: - Planck time (PT): 5.4×10−44 s - Planck length (PL): 1.6×10^-35 m - Electron radius (EL)...
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