It's Elemental

Tag: Infinite Number

  • Chaos theory and fractals – 5/4 (!?!)

    Chaos theory and fractals – 5/4 (!?!)

    A response to the question: “How is chaos theory non-determinant?”

    This is an interesting question, because I think it might normally be asked in the opposite way: “How is chaos theory DETERMINANT?”, because chaos theory is, well, chaotic, so it seems more logical to connect chaos with non-determinancy than with determinancy.

    So to explore the question that wasn’t really asked:
    The techniques which we have discovered that allow us to analyze systems that exhibit chaotic behavior are completely deterministic: they are mathematical in nature, having the feature of acting like an Ouroboros, where the output becomes the input in a recursive cycle.  We can start with even very very simple systems, and show how chaotic behavior results when the system evolves, when that system’s evolution takes place in ways describable by this type of recursive mathematics (not all systems are so describable).  Really the MATH isn’t the thing here, it’s rather the RECURSIVE PROCESS, RULE, or PROTOCOL that is important.  The math is just a really nice and clean way of expressing the essence of what happens when a system evolves by following a recursive rule.

    So chaos THEORY is determinant in that the rules which it utilizes to describe evolving systems have the potential to be calculated EXACTLY from iteration to iteration.  In other words, if we had a computer that could deal with an infinite number of digits we could theoretically pinpoint the next iteration describing the state of a system at the next moment with complete precision.  BUT, there are serious caveats to this when applied to anything beyond the purely mathematical formulations themselves.  REAL systems may be more or less calculable, more or less complex, and more or less willing to submit to the precision capable in theory.  The determinacy of chaos theory is therefore more like a theoretical determinacy, having a dubious ontological status.  I won’t get into the very crazy and amazing philosophical arguments that whirl around such things, to your immense relief.  Suffice it to say that THE WORLD IS MYSTERIOUS, and we have to be careful when dealing with the connection between our thinking and our observing.

    The ‘problem’ with chaos theory is that we can’t observe closely enough to know where to START our calculations, so we ALWAYS know that they are ‘wrong’ when dealing with the actual observable world.  This is that ‘sensitive dependence upon initial conditions’ thing again: there is no lower limit at which a difference does not potentially make a difference, even ALL the difference.  In other words, even the smallest possible change cannot be ignored.  The thing is that we can never know ahead of time when such a difference may be either influential or inconsequential – we have to let the system evolve in actuality in order to find out.  We can’t calculate the future states of the system (which are theoretically determined!) with much success because (depending upon the system’s complexity and initial state) as soon as we get a few iterations under our belts our calculations tend to diverge from other initial states that were infinitesimally close to the one we are actually calculating. So our results tend to be so far off from what we will later actually observe that we start calling the whole thing a theory of CHAOS, even though every step in the process is ‘determined’; hence “deterministic chaos”.  So even today a large bulk of weather predictions are based not off of complex theories of high pressure and low pressure zones, temperature gradients, moisture content, and such, but rather simply off of a comparison with past ACTUALITIES.  Predictions START with a comparison of the averages for a particular place for that same day in previous years, because this is often a better predictor than if we were to try and start with vastly incomplete current data.  The best predictions, of course, blend the two methods, but you’ll notice that nobody (okay, this isn’t true, but such people have completely different methods for prediction) is giving weather predictions much beyond a week or two at best.  This isn’t just a fault of our weather theory, but is a consequence of the RECURSIVE NATURE OF NATURE.

    So what is interesting is that our understandings from quantum physics put us in the strange position of having to admit that WE CAN NEVER HAVE PERFECT KNOWLEDGE of the state of any system – no matter how simple.  So we can’t even hold on to some ‘theoretical’ exactness that would be possible if only we had better instruments, or more complete observations.  THERE IS NO SUCH THING AS A COMPLETE OBSERVATION — at least in the sense of what had been the promise and holy grail of physics before the s**t hit the fan with relativity, quantum mechanics, Gödel, and chaos theory.  It turns out we live in a dirty universe, which is much more crazy and mysterious than we had imagined or hoped.

    Kevin Van Aelst, The Cantor Set (fried egg), 2004

    But what is key here is that chaos is not a result of linear progressions, but is more or less inherent (in systems with almost any level of complexity) when the Ouroboros steps in and finds its tail: recursion yields chaos.  I find this fascinating, because so many (all?) parts of the natural world utilize recursion as a technique — particularly in the living realm, but even in the purely mineral realm as well.  Whenever nature comes up with a new process it tends to repeat itself if the conditions allow it.  This repetition can easily become recursive, where some aspect of the process acts upon or is acted upon by some other aspect of the process.  When this happens you usually either get a complete breakdown or cessation of the process (a sort of suicide process, sometimes through growth), or you get emergent complexity, homeodynamic systems, self-regulating organization, and the basis for higher-level recursions.

    At the same time, every recursive process is — although perhaps potentially infinite — embedded in a contextual situation that provides limits and boundaries to the system’s evolution.  Sometimes it happens via a law of physics, sometimes as a consequence of mathematical relations in the context of physical laws (as in the increase in volume with the cube and the surface area with the square), and sometimes it’s just the seemingly contingent facts of context (it doesn’t rain that year, the food runs out, the salinity changes slightly, and so forth).  The point is that these contextual limitations are not usually a part of the chaotic models proper.  Rather, the chaotic models become themselves modified by through a corresponding synthetic analysis of contextual facts.  The Mandelbrot fractal is what it is because it does not have to evolve in the context of anything REAL; it is an ideal form through and through.  This is why we only find approximate fractals in nature, forms which approach the self-similar repetition of mathematical models.  But rather than say that nature’s forms approximate mathematical laws, maybe we should say that our mathematical laws approximate nature’s forms.  Maybe the laws we use to think about these forms are one of the ways that nature involves itself in a sort of grand recursion; the mathematical laws are like a high-level iteration of a process which at a lower level is much more messy and dynamic, but now has the benefit of taking place completely within the consciousness of a human being, thus allowing it to reach a new level of emergent complexity, i.e. the laws of emergent complexity themselves.

  • Chaos theory and fractals: 4/4

    Chaos theory and fractals: 4/4

    4. I don’t understand how the butterfly effect looks like the structures seen in the book…a butterfly looking pattern.

    The butterfly effect is just the name, slightly arbitrary, of the idea that complex systems exhibit the characteristic by which tiny tiny tiny (infintesimally tiny) changes in one part of the system have the potential (not always actualized) to transform THE ENTIRE system, on all its scales.  The Lorenz attractor kind of has the shape of a butterfly, and can be an image that is used to explain this sensitive dependence on initial conditions, but don’t worry about linking the Lorenz attractor specifically to ‘regular space’.

    Drawings like that are actually drawings in what is known as “phase space”, which is simply an N-dimensional space where each dimension is represented by a change in ONE variable.  The point of such diagrams is that they can incorporate simultaneous changes in many different variables at the same time (although visually there are limits on how to do this, because we are always projecting back into 2D space; holograms would help, but would only add 1 more spatial dimension in which to visualize, whereas there can be an INFINITE number of dimensions to map, depending on the phenomenon and how complex we get in our analysis).

    A dimension here is just the abstract space in which any single variable can be tracked, such as distance (up/down, left/right, forward/backward, yielding 3 dimensions that can be mapped in phase space), time (adding a 4th dimension in phase space), or anything else that we want to track, like ‘population number’ or ‘frequency/color’ or ‘subjective happiness rating’ or ‘distance from Antares’ or ‘fractal dimension’ or WHATEVER.

    If you wanted to plot two of those variables you could do it on a simple cartesian XY graph; this is a 2D phase space.  If you want to track three variable simultaneously, you need to add an extra axis, giving a 3D phase space.  But you can graph things in unique ways, for example by varying the color according to some rule that links the color with a variable, say temperature (you’ve all seen graphs and maps like this).  You can use more tricks to get more data in a phase space plot, but when it gets beyond 3 or 4 dimensions most scientists (and mathematicians especially) drop the visualization completely and just stick with the math — you get tables of numbers, each ‘row’ representing, for example, the state of the thing you are tracking, including all of its possible variables at that moment.  The next row would show the state at the next moment, and so forth.  Then you can just choose two or three of the possible N-dimensions and graph them against each other, and then take a new set, and so forth, until you see patterns.

    FROM WIKIPEDIA: BUTTERFLY EFFECT

    These figures show two segments of the three-dimensional evolution of two trajectories (one in blue, the other in yellow) for the same period of time in the Lorenz attractor starting at two initial points that differ only by 10−5 in the x-coordinate. Initially, the two trajectories seem coincident, as indicated by the small difference between the z coordinate of the blue and yellow trajectories, but for t > 23 the difference is as large as the value of the trajectory. The final position of the cones indicates that the two trajectories are no longer coincident at t=30.

    Cool java applet showing the same principles: http://to-campos.planetaclix.pt/fractal/lorenz_eng.html

  • Chaos theory and fractals: 1/4

    Chaos theory and fractals: 1/4

    The following four questions (one per post) were posed in a recent class. My edited responses follow.

    1. So I understand that any shape in nature can be converted to a mathematical formula, right? Then you take that formula and plug in the variable related to that shape and feed the answer into the variable spot in the next equation, continuing that as many times as one wants (with potential infinite number of times).   Here is where I get stuck.  Does each answer produce a smaller version of the original shape or does the answer produce the snowflake-like shape of the whole, complex, product?

    We do not know how to find mathematical functions for every shape in nature; indeed this is still an area of active research.  Usually we can model (i.e. approximate) natural shapes with mathematical functions, but nature is a little more slippery and variable than the stark purity of mathematics proper, so we don’t get exact results.  This isn’t usually a problem, however, because the whole point is that we can occasionally find mathematical functions that provide something of the… essence of the form.

    For example your lungs are fractal in nature, branching and branching and branching… but they don’t do it in only one way.  Rather, they have different ‘stages’ of branching, each with a different ‘fractal dimension’, depending on how many previous branches lie before it (I can explain what a fractal dimension is if you wish in another post).  (Read a single page about this from the Cellular and Molecular Life Sciences journal – slightly technical but you can probably get the basic idea through a different lens, which is always useful: http://www.springerlink.com/content/q103206u70402617/)

    But to answer the question directly re: “each answer…”,  most fractals both occur and are described by the taking of a single set of relations (it may be a shape), and repeating that relation/shape on different scales, with rotations, translations (moving without rotating), etc.  In other words, you start with a thing and then put it through some sort of process, then take the new whole that results and do the same process to it again, and so forth.  What is interesting is that a pattern emerges out of the process… and the process is primary, NOT THE THING.  In fact, you can take ANY shape, and subject it to a specific process over and over, and you will get the SAME fractal form, regardless of the original shape.  So each iteration (“each answer”) is a further unfolding of the process, a more ‘detailed’ rendering of the pattern inherent in the unfolding of the process.

    So it’s not just a question of “smaller versions” or of reproductions of the “whole”; the pattern that defines the particular fractal is really the expression of an infinite process (usually based on some pretty simple and limited rules, like “rotate 36 degrees counter-clockwise and scale by a factor of 1/2”), which can be “reversed” (rotate 36 degrees clockwise and scale by a factor of 2) – so size has nothing to do with it, and you can start anywhere in the process with whatever you have, because the thing isn’t ‘the thing’ if you know what I mean: ‘the thing’ is the process.  This is very good for nature because nature can take whatever is there and do some pretty simple things and get some very complicated results.  It doesn’t have to start with a ‘grand plan’ that requires everything to be exact and fit in just the right way in order for it to ‘work’, but can just take whatever is there and MESS AROUND.  This isn’t the whole story but I’m just trying to relate this to fractals specifically.