Reading Game of Life descriptions feels like reading papers about quantum physics :)
Which creates some disturbing ideas about our reality.
I'd implore everyone to spend a few rainy weekends trudging through Mandelbrot's 'The Fractal Geometry of Nature'[1] and Wolfram's 'A New Kind of Science'[2]. Both are rather terse, but I found both added a whole new depth of analogy in the way I see the Universe(s).
It's easy to be dismissive of Stephen Wolfram for his general asshat'ery and Benoit isn't around to champion his notions in the broader sense. But if we are to take reductivism to it's extreme, it's worth exploring emergent patterns with a bit more wonderment.
[1] http://books.google.com/books/about/The_Fractal_Geometry_of_...
Yes. The universe only has so much computing power, and any universe we simulate will have less.
Here's a relevant paper by Lloyd titled "Ultimate physical limits to computation": http://arxiv.org/abs/quant-ph/9908043v3
Another disturbing thought: if our universe were spun up or down like we do virtual machines, would we even notice?
I would guess not. See Permutation City by Greg Egan for lots of speculation about questions like that.
Life provides an example of emergence and self-organization. It is interesting for computer scientists, physicists, biologists, biochemists, economists, mathematicians, philosophers, generative scientists and others to observe the way that complex patterns can emerge from the implementation of very simple rules. The game can also serve as a didactic analogy, used to convey the somewhat counter-intuitive notion that "design" and "organization" can spontaneously emerge in the absence of a designer. For example, philosopher and cognitive scientist Daniel Dennett has used the analogue of Conway's Life "universe" extensively to illustrate the possible evolution of complex philosophical constructs, such as consciousness and free will, from the relatively simple set of deterministic physical laws governing our own universe.
If you go deep enough, it really is a fascinating thing. Even more-so given the extreme simplicity of its rules.
[1] http://en.wikipedia.org/wiki/Conways_Game_of_Life#Origins
But I am still curious as to who has the time to engineer with them? Is it just "hobbyists" or do some academics derive useful work out from pursuing them?
The excessive search for "useful work" is one of the bigger problem of academia today. Even the most practical research usually doesn't look useful at the beginning, and pursuing things that seem immediately applicable to real-world problems can be a form of premature optimization. Not to say we shouldn't pursue the "practicality" route at all, but today most research seems to be optimized for short-term money generation and/or fame.
Anyway, cellular automata are a separate research field, and I'm pretty sure that some of those game-of-life engineers are academics who are doing this as research because it's fun/interesting. And hail to them, because those hobbyst-scientists create tools that enterpreneurs can forge progress with.
Self-organization is fascinating stuff; I suppose the economic corollary would be the "invisible hand." But in this example, is there not a "designer" setting the "simple rules" that make the self-organization possible?
And no, those aren't encoded in Life's rules. They are merely allowed by those.
Edit: You're right, people put a lot of time into discovering and engineering things in Life. But it's an odd mix of cleverness and brute-forcing. http://www.conwaylife.com/wiki/Glider_synthesis
[edit] Someone put a nice animation of the replicator here: http://en.wikipedia.org/wiki/HighLife
I corresponded with Gardner once or twice, and subscribed to Robert T. Wainwright's Lifeline newsletter, which had begun a taxonomy of Life objects and reported community progress. Our little group was surprisingly competitive in the beginning, considering the limited resources at our backwater university, but when the MIT group kicked into high gear the exploits of Gosper, Woods and others at MIT were simply mind blowing. Woods' Atavist backtracker, Gosper's Glider Gun, the first discovery of a Garden-of-Eden configuration... who could compete with that? And Gosper continued to amaze with his astonishing Breeder.
Conway's GoL inspired other acquaintances, electrical engineers. One of them built a special-purpose computer to compute generations; he'd have surprised to know then that the computer was Turing-complete. Another EE pal built a crude raster display for the lab's Nova 1220 mini, with the specific intent to display GoL generations. Hardly such a thing as glass TTYs in those days, kids.
Sorry for the free-association; you know how old guys get. Think I've still got my old stack of Lifelines around, stored in the garage. Maybe I'll haul 'em out like an old yearbook, and see how they go with a Stone Levitation.
Scan them! And drink, the Stone, of course.