(define-theory Granularity (Layers))

(in-theory 'Granularity)


(DEFINE-RELATION _ACTUAL (?A ?B)
 "The granularity of things whose nature is 
described as they actually are.
This is typically done in some variety of straightforward first-order logic.
For example, the predicate 'spherical(x)' can never be absolutely true of any
physical object at the '_actual' granularity."
 :DEF (LAYER ?A ?B))
(DEFINE-RELATION _EPISTEMIC (?A ?B)
 "The granularity of things whose nature is 
described as they are acknowledged, thus it depends on experimental evaluation, 
degree of certainty, etc.
This is typically done in some variety of epistemic logic (it requires at
least the meta-level predicates: 'knows' and 'believes'.
For example, the predicate 'spherical(x)' is true of any
physical object at the '_epistemic' granularity if no imperfections are 
detected by the measuring device used (even body senses)."
 :DEF (LAYER ?A ?B))
(DEFINE-RELATION _INTENTIONAL (?A ?B)
 "The granularity of things whose nature is described 
as they are considered by some agent.
This should be done by adding a triadic predicate which relates an agent, an 
entity, and a reason (eg reason(a,e,r)).
For example, the predicate 'spherical(x)' can be true of any
physical object at the '_intentional' granularity only because an agent wants
to consider it so for some reason, for example approximating a sphere-like
for computing an orbit, a speed, etc."
 :DEF (LAYER ?A ?B))