Diagrams of links drawn with tagged arrows between dots can represent vast tracts of mathematics and science. Even though, I argue, there is more to nature than physics and mathematics, there is much that can be modeled. In particular, a simple extension of the standard idea of finite state machine, called timing machine , may be represented by links. I have used timing machinery to model biological neurons, thermodynamic theorems, and cybernetic machines. An explanation of purpose in terms of a mental model of the situation, called a now , is advanced.
Nows are the subjective parts of nature.
The concept of situation must be explained, ultimately, in terms of the history of the whole physical universe, and an indication is provided of how that might be done using elementary concepts from a theory of quantum cosmology.