316 Are the Androids Dreaming Yet? | a. ( “s cu if Mm J " at Jae it mel oe hs f 4) ee fA THAR 4 a ( f | ()) rs \ és Syren PAR Ll re + Sei atin XE | 5 nan inh LLL “ue Wedaias caaert \ pa Muh WW \ Domino Toppling Determinism To firmly grasp the idea of determinism let’s look at a fun example, domino toppling. If I arrange a set of dominoes on their edge in a long line and push over the first it will fall, knock over the next, then the next, and so on until all the dominoes have fallen. It is inevitable, and fun to watch. The same is thought to happen with particles in our Universe, albeit at a much smaller scale. The laws of physics governing these particles describe precisely what will happen as they interact. Our Universe could be thought of as a mechanical clock, wound and set at the Big Bang, or a fractal equation generating the wonders we see around us. When I push over the first domino it should be possible to capture all the information about the particles in the dominoes, my hand, the table, and the surrounding environment to precisely determine what will happen next. Will all the dominoes fall perfectly, or is there a break in the pattern — one domino just a tiny bit out of alignment — which will spoil the fun? All the information is there in front of me and I should be able to predict it perfectly. The laws of physics, as we understand them, are not only deterministic, they are reversible. This means if we know the position and momentum of every particle in the dominoes and the surrounding environment, we can extrapolate their motion back into the past. It should be possible to trace back the path of each particle to reconstruct the past history of the dominoes. If we were to cast a wide enough net, and collect all the available information, we could go back and see the events in the factory where the dominoes were made, or even see the trees that was felled to make them. We would need a Jot of information and huge computing power, but we could do it! Wit