00100		CHAPTER 9
00200	
00300	   MODEL EVALUATION
00400	
00500		In the background of an evaluation procedure for a model lies
00600	the question - `is it a good model?' The ordinary language term `good'
00700	means praiseworthy. But what is a model good at or good for in order to
00800	be praiseworthy? As stated in %00 our primary aim in constructing this
00900	model was to explore and test a theory having explanatory verisimilitude.
01000	How cam we decide whether or not the model provides a `good' explanation
01100	of certain paranoid phenomena?
01200		A model in the form of an algorithm consists of a structure of
01300	mechanisms whose inner workings are sufficient to generate the outward
01400	behavior under consideration. The theory embodied in the model is
01500	revealed by the set of statements which describes how the structure
01600	reacts under various circumstances.
01700		Theories have many functions. They can be summarized as follows
01800	[from Bunge?]
01900		(1)To systematize knowledge.
02000		(2)To explain facts by showing how they are the entailed
02100	              consequences of the systematizing hypotheses.
02200		(3)To increase knowledge by deriving new facts.
02300		(4)To enhance the testability of hypotheses.
02400		(5)To guide research by:
02500	              (a)posing fruitful problems
02600	              (b)suggesting new data to gather
02700	              (c)opening new lines of investigation
02800		(6)To map a portion of reality.
02900		It is a tall order for a theory to fulfill all of these
03000	functions. In undeveloped fields we should be happy with even one
03100	of them. Models can be assigned  these functions when they are
03200	theoretical, rather than replicative, in type. Our model was intended
03300	primarily to serve functions (2) and (4), testable explanation.