Intuitively, the best way to do this would be to build “sensors” and “effectors” to have inputs and outputs and then have some program decide what the effectors should do based on the input from the sensors.
I think this is extremely hard to impossible in Conways’ Life, if the remaining space is full of ash (if it’s empty, then it’s basically trivial, just a matter of building a lot of large logic circuits, so basically all you need is a suitable compiler, and Life enthusiasts have some pretty good ones). The problem with this is that there is no way in Life to probe an area short of sending out an influence to probe it (e.g. fire some pattern of colliding gliders at it and see what gliders you get back). Establishing whether it contains empty space or ash is easy enough. But if it contains ash, probing this will perturb it, and generally also cause it to grow, and it’s highly unpredictable how far the effect of any probe spreads or how long it lasts. Meanwhile, the active patches you’re creating in the ash are randomly firing unexpected gliders and spaceships back at you, which you need to shield against or avoid being in line of fire. I think in practice it’s going to be somewhere between impossible and astoundingly difficult to probe random ash well enough to identify what it is so you can figure out how do a two-sided disassembly on it, because in probing it you make it mutate and grow. So I think clearing a large area of random ash to make space is an insoluble problem in Life.
Fundamentally, Conway’s Life is a hostile environment for replicators unless it’s completely empty, or at least has extremely predictable contents. Like most cellar automata, it doesn’t have an equivalent of “low energy physics”.
I think this is extremely hard to impossible in Conways’ Life, if the remaining space is full of ash (if it’s empty, then it’s basically trivial, just a matter of building a lot of large logic circuits, so basically all you need is a suitable compiler, and Life enthusiasts have some pretty good ones). The problem with this is that there is no way in Life to probe an area short of sending out an influence to probe it (e.g. fire some pattern of colliding gliders at it and see what gliders you get back). Establishing whether it contains empty space or ash is easy enough. But if it contains ash, probing this will perturb it, and generally also cause it to grow, and it’s highly unpredictable how far the effect of any probe spreads or how long it lasts. Meanwhile, the active patches you’re creating in the ash are randomly firing unexpected gliders and spaceships back at you, which you need to shield against or avoid being in line of fire. I think in practice it’s going to be somewhere between impossible and astoundingly difficult to probe random ash well enough to identify what it is so you can figure out how do a two-sided disassembly on it, because in probing it you make it mutate and grow. So I think clearing a large area of random ash to make space is an insoluble problem in Life.
Fundamentally, Conway’s Life is a hostile environment for replicators unless it’s completely empty, or at least has extremely predictable contents. Like most cellar automata, it doesn’t have an equivalent of “low energy physics”.
Sounds plausible! I haven’t played much with Conway’s Life.
(Btw, you may want to make this comment on the original post if you’d like the original author to see it.)