Crutchfield introduced a conceptual device called the epsilon (ε) machine. This device can exist in some finite set of states and can predict its own future sta

Crutchfield introduced a conceptual device called the epsilon (ε) machine. This device can exist in some finite set of states and can predict its own future state on the basis of its current one. It’s a bit like an elevator, said Rosas; an input to the machine, like pressing a button, will cause the machine to transition to a different state (floor) in a deterministic way that depends on its past history—namely, its current floor, whether it’s going up or down, and which other buttons were pressed already. How is this different from a turing machine?