Comments

  • The Reality of Time
    Indeed, and if time is not composed of instants, then it must be continuous.aletheist

    Would that imply time is also "smooth?" Or space/time?
  • Mathematics is 75% Invented, 25% Discovered
    Strictly speaking, math is just like theoretical physics: it's a branch of philosophy.Gregory

    Oh no, no, no . . . anything but that! :scream:

    I think mathematicians should consider philosophy thru considering substance.Gregory

    There's always the danger of abuse. :gasp:
  • The Reality of Time
    Once again I attempt to get the conversation about time moving in a slightly different direction:

    Wiki: "With an incomplete theory of quantum gravity, it is impossible to be certain what spacetime would look like at small scales. However, there is no reason that spacetime needs to be fundamentally smooth. It is possible that instead, in a quantum theory of gravity, spacetime would consist of many small, ever-changing regions in which space and time are not definite, but fluctuate in a foam-like manner.[3]

    Wheeler suggested that the Heisenberg uncertainty principle might imply that over sufficiently small distances and sufficiently brief intervals of time, the "very geometry of spacetime fluctuates".[4] These fluctuations could be large enough to cause significant departures from the smooth spacetime seen at macroscopic scales, giving spacetime a "foamy" character."
  • Mathematics is 75% Invented, 25% Discovered
    And I know mathematicians can hate philosophers :)Gregory

    Not really. We are quite tolerant, and chuckle as we do when a cute puppy barks. :smile:

    Indeed, mathematics is 75% invented, 25% discoveredGregory

    The controversy among mathematicians whether math is discovered or created has finally been laid to rest. Thank you, Gregory! :cool:
  • Joe Biden (+General Biden/Harris Administration)
    I am 83, and from my perspective both Biden and Sanders are too old for the presidency. The Democratic choice for vice president is far more important. Biden may win the top job, but the VP will gradually take over behind the scene. So who might that be? :chin:
  • Mathematics is 75% Invented, 25% Discovered
    Since numbers by themselves sit in their own world within the human imagination, you can always make up your own rules as you go with postulations, right? Go ahead. That's pure mathematics research right there.flame2

    If you say so. :roll:
  • The Philosophy forum: Does it exist?
    The forum exists. I have my doubts about philosophy. :chin:
  • The Reality of Time
    Here's a thought. These arguments about the nature of time go on interminably without clarification, repeated over and over. Why not try a different approach:

    Momentum, from physics, is defined as mass times velocity: momentum=mass x ds/dt.
    Why not try to define "momentum" and "mass" and "distance" for the evolution of ongoing events, then define an increment of time by: dt=mass x ds/mom? :chin:

    Don't ask me how. Someway define the process of multiplication and division in the equation.

    Or return to formal logic and proceed.
  • The Reality of Time
    consistent with my contention that continuous motion is the fundamental physical reality, while discrete positions in space and instants in time are artificial creations of thought to facilitate describing such motionaletheist

    Here is Peter Lynds' paper in which he postulates that there are no instants of time. This was published in Foundations of Physics and generated heated arguments, with a strong contingent of physicists declaring it nonsense. But who knows? Lynds is or was a college dropout.

    https://arxiv.org/ftp/physics/papers/0310/0310055.pdf
  • Infinity and Zero: do they exist?
    We can talk about infinity in percentages though.Zelebg

    Novel notion, Z! How would you describe 50% of infinity? :chin:
  • What are Numbers?
    Having spent an entire math career not concerned with these things, I now find there is literally no escape: https://en.wikipedia.org/wiki/Reverse_mathematics

    I wasn't even aware of this before opening the brochure I got in the mail today from the Princeton Press.

    :worry:
  • Length and relativism
    Comparing infinities using different measures (density vs cardinality) that contradict each other proves the mathematicians don't have any idea of what infinity isGregory

    Who is comparing? Please show how the two compare. How do they contradict each other?

    https://www.encyclopediaofmath.org/index.php/Density_of_a_set#Density_of_a_measure

    Wiki: In topology and related areas of mathematics, a subset A of a topological space X is called dense (in X) if every point x in X either belongs to A or is a limit point of A; that is, the closure of A is constituting the whole set X.

    Wiki: The relation of having the same cardinality is called equinumerosity, and this is an equivalence relation on the class of all sets. The equivalence class of a set A under this relation then consists of all those sets which have the same cardinality as A.
  • Simple proof there is no infinity
    What is TS?fdrake

    Topological space.

    On every page there is a description of a single particle, where it is, what is doing at the given time. Collectively all that information describes everything that exists and will ever exist.Zelebg

    Let's say particle alpha is under consideration. We measure time in seconds. Page 1, present time. Page 2 , 1 second from now. Page three, 2 seconds from now, etc. Page N, N-1 seconds from now. You would have to assume time stops at some point in the future in order to secure your "proof." So you would postulate that time is finite. But this seems to be part of what you wish to prove.

    I must be missing some important debate points here, in my old age. :gasp:
  • Simple proof there is no infinity
    Therefore, the total number of unique bits of information is finite, or there is some kind of information your monitor can not display, for some reason.Zelebg

    Say each piece of information is a string of alphabet symbols. Since the length of these strings is unbounded, so is the amount of information. We're not talking about computer programs that terminate.

    Do you know what kind of properties a space would need to have so that every subset of it could be covered by a finite set of polygons?fdrake

    Compactness? Are your "polygons" abstract entities? Topological spaces or what? Compactness in TS if you adjoin limit points, I suppose. :nerd:
  • Simple proof there is no infinity
    You don't get it, you can zoom in as much as you wish in arbitrary small steps.Zelebg

    Wow! So there are an infinite number of pixels in each photo. You're correct. Guess I don't get it.

    You can also forget photographs and imagine all the knowledge there is about everything that will ever be is simply written in English words, with illustrations and diagrams.Zelebg

    There are a finite number of existing English words, but if there is no limit on the length of a word you could be speaking of infinities. There are 26 letters, so how many "words" could be constructed, of any length? Of two letters: 676. It goes up from there. 26^n. n increases without bound. Also, there could be an infinite number of diagrams.

    Is the map the territory?
  • Simple proof there is no infinity
    Well, no, the number of distinct digital photos of a given resolution is finite. But so what?SophistiCat

    Of course. The entire process is faulty. The assumption that every aspect of the universe can be so pixeled assumes his conclusion.
  • Infinity and Zero: do they exist?
    It's interesting to note that the duration of time has seemingly decreased throughout history.3017amen

    Please cite a legitimate reference. Is this claim related to the observation that time seems to pass more rapidly as we grow older? A psychological phenomenon.

    To terminate this discussion let me reveal that on my desk is a small Egyptian box, 5cmX3cmX1cm, in which I keep both zero and infinity. So you have my word that, yes, they do exist. :cool:
  • Simple proof there is no infinity
    Yet the number of all those possible photos is not infinite.Zelebg

    Faulty hypothesis. :yawn:
  • Length and relativism
    It's a bridge though to Eliatic realms however, a secret door though that mathematicians don't know aboutGregory

    Wiki: "The Eleatics maintained that the true explanation of things lies in the conception of a universal unity of being. According to their doctrine, the senses cannot cognize this unity, because their reports are inconsistent; it is by thought alone that we can pass beyond the false appearances of sense and arrive at the knowledge of being, at the fundamental truth that the "All is One""

    More like a trap door IMHO. :roll:
  • Does Relativity imply block universe?
    Yes, it's difficult to square what appears as a very dynamic universe with block structure. All the mathematics I dabble in involves patterns of movement, so I am biased. :cool:
  • Length and relativism
    At this point all our intuitions fail, and we must adopt some form of relativism or say we know nothing of math whatsoever.Gregory

    It's not that bad. Really. :roll:
  • Eastern philosophy thread
    Here's where you need someone who has experienced this kind of enlightenment. I engaged in Zen practice for a short time a lifetime ago, but did not reach that stage. A friend who has had the experience says one's "I" perspective drops away and there appears to be an empty stage of awareness, a "no-thingness", and the various koans are comprehended (?). "Form is emptiness and emptiness is form" - that sort of thing.

    This is an amateurs' forum, so one doesn't expect credentialed experts to spend time here. Still, with over 6K members there might be one who has real Zen experience?
  • Why is it that, "I will create more jobs than anyone else..."...
    For some reason this thread is not coming up on the forum page for me.
  • A new normative theory and a PhD thesis
    How about it, Dan? Get your degree? :smile:
  • Is Cantor wrong about more than one infinity
    As Tristan L has so generously and perspicaciously explained, the proof adduces a one-to-one function from the naturals onto the odds, and that is all that is needed.GrandMinnow

    This should put an end to the issue. But it won't. :roll:
  • Why is it that, "I will create more jobs than anyone else..."...
    I suggest someone who is a proponent of "more leisure time" try starting a GoFundMe account. This might provide a "peoples'" perspective on the idea.

    My two areas of relative expertise are mathematics (classical complex analysis) and climbing. Regarding the latter, I have seen the American Alpine Club shift its priorities over the years, from preserving history and sponsoring Himalayan expeditions to raising money to give to youngsters so they can go play on the rock. And some of those young climbers avoid medical insurance, assuming a GoFundMe account will pay for their injuries. More supported leisure time. I compare this with the environment sixty years ago, when a friend who was living day to day, a "dirtbag" climber, rose on his own merits over the years to become a California billionaire.

    However, even in a good economy like the present with plenty of jobs, many young people live in the "gig" world, moving from one temp job to another, with limited benefits. I see this in the academic world where tenure-track positions become adjunct appointments, with virtually no benefits.

    So, I have mixed feelings on the issue. :chin:
  • The Road to 2020 - American Elections
    How devastated and crushed and angry and heartbroken they're all going to be when the DNC steals the nomination from Berniefishfry

    And how they will not vote next November, to show their frustration.
  • Eastern philosophy thread
    I'd suggest Zen Buddhism, but it's more a practice than a philosophy.
  • The Road to 2020 - American Elections
    The cost of housing may be going up in many areas that have been reasonable in the past. I live in a nice middle class prairie community south of Colorado Springs with a population of about 40K, ten miles from a city of 100K where half the population is on medicaid. Until a couple of years ago one could buy a fairly new three bedroom house with three bathrooms on 2.5 acres with unrestricted views of Pikes Peak and the Wet Mountains for $250K. Yesterday I saw a house down my street go up for sale for $450K. This house would probably go for a million bucks in a comparable region of California.

    Colorado has become a blue state, and our governor admires and wants to emulate California. May the saints preserve us . . .
  • The Epistemology of Visual Thinking in Mathematics
    As far as I am concerned, the only thing that really helps, are good examples, which are almost always lackingalcontali

    Good point. The only trait I share with R. Feynman is the process of learning a difficult concept by looking at examples. There are many mathematicians who can understand abstract notions very quickly simply by the words and symbols describing them. I envy them this ability. By studying examples it all clicks into place for me.

    Many years ago I knew of a graduate student who spent a couple of years working up his PhD research project on a class of functions. Then one day he was asked for an example. A fruitless endeavor, for he soon learned the set of such functions was the empty set. :worry:
  • Entropy can be reset to a previous or to an initial state
    The conversation has drifted into ergodic theory rather than entropy. :roll:
  • The Epistemology of Visual Thinking in Mathematics
    That article does go on and on. I burned out after a short spell. Fifty years ago I was formulating my dissertation and was stuck at a difficult point involving a kind of infinite iteration. As I was lying in bed one night, beginning to drift off, I suddenly envisioned a geometrical image that provided a key to completing both the structure and proof of a difficult theorem. I still do a bit of research and imagery is important, although it's rare that a proof itself relies on geometrical figures.

    At one time it was required that a student take a course in analytic geometry prior to an introduction to calculus. All the imagery in that course provided a bridge of understanding for calculus. Nowadays, that material is squeezed into calculus, and there are even calculus curricula that attempt to minimize imagery by going into n-dimensional vector spaces immediately.
  • Intelligent design; God, taken seriously
    If there are an infinite number of universes, there is one where the contents of this entire forum were created by monkeys randomly typing at keyboards.Douglas Alan

    A countable or uncountable number of universes? Would there be a difference? :chin:
  • Entropy can be reset to a previous or to an initial state
    Assuming equal probability, the finite number of states simply means that the fewer the states the higher probability one re-occurs over a lengthy series of experiments. And as the number of states increases without bound ("goes to infinity"), the probability of a particular state shrinks toward zero. Roughly speaking.

    The function has to do with the mixing of the particles, say, from moment to moment. Without preservation of "area" the distance between two points might shrink each iteration, and the configuration one would like to see re-emerge would not be possible. Roughly speaking.
  • Intelligent design; God, taken seriously
    By "intelligent design" one seems to imply some sort of entity that "causes" that phenomenon. But what if the design appears to be a product of intelligence when in fact it may not be? Is there effect without cause? All most of us ever see in this world is effect resulting from a cause, or a host of causes. Thus, we question, What was "before" the Big Bang? Suppose the Universe is different, but we "see" what we are accustomed to seeing. Then time reversal in mathematical equations in physics might describe reality better than normal perspectives. We simply can't see or process what is "really" out there.

    Just babbling. Pay me no mind. :chin:
  • Entropy can be reset to a previous or to an initial state
    My understanding was akin to shuffling a deck of cards a lot of times.tim wood

    Yes, I'm not sure what further if any conditions would be placed on that experiment. Combinatoric calculations in probability. Here is a comment from Geology Wiki:

    "The Poincaré recurrence time of certain systems is the time for them to revert to a state almost identical to their current state. The system should satisfy the following properties:

    1. All the particles in the system are bound to a finite volume.
    2. The system has a finite number of possible states.

    The universe might not satisfy these properties."

    Mathematical theory of PR is pretty strict. :cool:
  • Entropy can be reset to a previous or to an initial state
    My contribution here is to refer to "Poincare recurrence." Easy enough to google. Very broad strokes: the idea is that in any system, wait long enough and some configuration of it will recurtim wood

    Too broad, IMO. This is a result that requires a function that takes points in the space under consideration back into that space. However, with regard to a measure defined on the space, the function must preserve that measure. This is quite restrictive. If I examine systems in the complex plane, using the normal Euclidean measure, the function seems to be a simple linear translation. Extremely restrictive.
  • Intelligent design; God, taken seriously
    As a (secular) retired mathematician, I think it prudent to keep an open mind on the subject of a non-religious notion of "intelligent design". Max Tegmark's Mathematical Universe Hypothesis could be so described. The question that arises is, Can there be ID without a specific designer? Or is that an oxymoron?