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Remote Ready Biology Learning Activities

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Exploring Emergence

The World of Langton's Ant:
Thinking about "Purpose"

Part 3D
Making Sense of the Observations:
Beyond Determinism ... Randomness as a First Mover?

Langton's ant, to a naive observer, seems to wander aimlessly and after a while to discover a purpose, to build a road. By now though we've come to recognize that there is nothing in the ant that represents the purpose of building a road. And there probably wasn't any intention to build a road in Chris Langton, the creator of the world of Langton's ant either. The world is simple enough so that it might have been put together more or less randomly, just to see what happened But there was a mind (Chris Langton's) and at least some purpose (to create something "interesting"?) that got the whole process started and resulted in the end in something that builds a road. Could we get a road without any mind/intention at all? Could something that looks like it was planned (a road) arise from something lacking any element of purpose whatsoever? Conversely, could something "aimless" actually be quite controlled? Let's think a little about that.

Comparing Deterministic and Random

To start, let's go back to the initial behavior of Langton's ant, the period when it seems to be wandering "aimlessly", without purpose. Was it really wandering "aimlessly"? Without "purpose"? In fact, as we now know, the ant was following during that initial period exactly the same set of rules that it was following later when it was building a road. It was moving not randomly but deterministically; its behavior was absolutely determined by a fixed set of rules. What exactly do we mean by "aimless"? Is it what the ant was doing or something else? You can explore this question by using the modified version of the world of Langton's ant to the right.

With "randomness" off, the ant follows the rules as in previous versions. With "randomness" on, the ant moves forward and changes the colors of squares just as before but it turns left 50% of the time and right 50% of the time irrespective of the color of the square (and irrespective of what it did on an prior move). Watch the ant move for a while (several thousand or so times) several times under each of the two conditions. What differences are there between "deterministic" and "random" behavior?

In the most general terms, this is actually a very subtle and currently unanswered question (which, of course, makes it a good one to be challenged by/think about as long as one doesn't feel one has to answer it any time soon). But there are some obvious differences between "deterministic" and "random" in this particular case. One, of course, is that when we restart the world with the original set of rules exactly the same thing happens, whereas when we start it with randomness on, something somewhat different happens each time. The ant also tends to go further from its starting point over any given stretch of time in the random condition than in the orignal one. As can be seen by the histograms, it also tends to revisit particular squares less and to visit more total squares in the random condition. This may be important if one is interested in exploration or the existence of free will.

Order From Randomness

Can one get a road in the random condition? Try it out. Remember though that you can't just try it once, since what happens will be a little different every time. You have to try it lots of times. And actually you don't have to try it if you don't want to because the answer is yes. Since a road is just a particular pattern of light and dark squares you WILL get a road sometime (just like you will get a Shakespeare sonnet if you randomly hit keys on a keyboard for long enough). That's important. Randomness can generate anything that can result from rules if you have enough time to wait. And that includes not only roads but things that make roads. Why be patient if you know what you want (eg a road)? No reason. But there are lots of reasons to be patient (and persistant) if you're curious. You never know what unexpected and interesting patterns might turn up from allowing some randomness to play a role (and you will always miss some possibilities if you always follow rules). Try running the Langton's ant for a while according to rules and then adding some randomness and see whether anything new or interesting turns up.

Are we and the universe we live in deterministic? or is there at least a bit of randomness in the world and ourselves? Could randomness (for example the "big bang") be the basic activity from which everything else, including purpose and ourselves, emerges? How important are rules and purposes? and how important randomness and fiddling/playing? There are no definitive answers, but these are some of the interesting questions that the world of Langton's ant poses and helps to think about. For a summary and some other views of Langton's ant, see the following page. And for some additional thoughts/reflections, see Further Considerations: Emergence and Further Considerations: Education.

"The World of Langton's Ant" was produced by Paul Grobstein with the Summer 2005 Serendip/SciSoc group. Applets were created with NetLogo by Rebekah Baglini, building on earlier work. Our thanks to the Emergent Systems Working Group for fertile conversations from which this emerged and to which we hope it further contributes.
Looking Inside
Agents/Environments | Observers | Architects | Beyond Determinism?
Summary and ...
Further reflections on Emergence and Science Education
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