The head of a Turing-machine

25 May 2014

The head of a Turing-machine doesn't know what it's doing. It reads, writes and moves back and forth. There is a controller that unambiguously tells it what to do, and the head just executes. In spite of that, every single step it makes is an indispensible part of a grand plan.

As far as the controller is concerned — maybe it was written by the head itself? It first made the plan, then started executing it, without stopping to think how far it is, how much more there is to do and if it should be done that way and not in a different way. Sometimes it seems to me that this head is actually pretty wise...