Frank Hutson Gregory

“ Abstract A number of logical problems in conceptual modelling can be solved by expressing the models in the form of universal statements. This leads to distinguishing two type of conceptual model, those used in main stream SSM and those used in Multiview, on the basis of whether the universals are definitions or inductive hypotheses. The models can be formulated in the predicate calculus and these formulations can be converted into the rules of Knowledge Based Systems. ”

“ SSM models and the real world If the universals that constitute the SSM models are definitions, then it follows that the models will be analytic rather than synthetic. That is, if they are true they are true by the meaning of the words alone. If this is the case, there is nothing in the conceptual model building process that guarantees that the models can refer anything that exist or could exist. There is nothing that prevents them from including references to unicorns, Greek gods and flying pigs. ”

“ Similar problems will arise for those people who consider that the only point in building a conceptual model is to change peoples' thinking. This is because a change in thinking can only be useful if it contains a reference, directly or indirectly, to an actual or potential real world state of affairs. ”

“ However, by using independent criteria for the particulars we can establish whether or not the model does or does not map on to the real world. In effect this make the model one large inductive hypothesis (the question of whether arithmetic is also a large inductive hypothesis will not be addressed here!) . The problem here is not theoretical but practical. The idea of an analytic model is difficult explain to many people. For example, the development of the models often requires the use of a number of extensive definitions (see Gregory 1992b) . ”

“ Most people would be likely to say that men are mortal because it has been observed that every man has died before, say, his 200th birthday. But for the Greeks "all men are mortal" was part of the definition of a man. ”

“ With the universals "All people who drop litter are bad" and "All bad people should be punished", and an instantiation, "Icabod drops litter", we can draw the conclusion: "Icabod should be punished". Value statements alone, will not, of course, account for the models that are, in fact, produced in SSM. There is no way that "All cases where a patient has been discharged are cases where treatment has been " could be construed as a value statement.
SSM prides itself on being able to deal with the human aspect of a problem situation. ”

“ The danger with Multiview is that in any given application the common language may fail to exist and may fail to develop. This danger is compounded by the fact that Multiview does not have the means to determine whether the common language is there or not. The Danger can be avoided if definitions were included into the Multiview model building process.
Conclusions Solutions to the SSM Problem One solution to the SSM dilemma is to take the model as consisting of a set of definitional universals which will map onto the real world if there are instantiations of certain particulars. ”

“ Once existence has been introduced existential consequences follow, such as , the fact that at least one patient has had treatment. Expressing SSM Conceptual Models in universals ties in well with the idea discussed above: that the models are models of concepts not models of what exists, necessarily, in the real world. The predicate calculus highlights this distinction and shows that the model will only map on to the real world if a set of particular statements are true. ”

“ Organizations tend to develop their own languages. The process of SSM conceptual model building could be taken to be a process whereby the stake-holders describe how this language is used. But if this were all that was going on the process would be quite simple and there would be no need for a lengthy iterative debate about the model.
Taking the SSM universals to be stipulative definitions is much more plausible. In this case the building of conceptual model is a process whereby the stake-holders come to agreement about how to use words to describe the problem situation. ”

“ It is, therefore, surprising to find that value statements have a very small role in the building of conceptual models. Value statements are usually implicit in the criterion for effectiveness and they can sometimes, but not always, be found in the Weltanschauung part of CATWOE. Apart from this they rarely appear. Despite the fact that the models are constructed in the language of imperatives these almost always turn out to be practical rather that value ridden imperatives. ”

“ The statements in these types of figure are always particulars. It it is unusual that a particular conclusion can be drawn from particular premises. Normally a particular will be deduced from a particular premise and a universal premise. An exception is simple conjunction, we can deduce "Socrates is a tall man" from the particular premises "Socrates is a man" and "Socrates is tall". Although figure 2 is not logically valid it is not false, and it can be made into a logically valid argument by adding universals. ”

“ Unstructured problems come about not because of a lack of structure in the real world but because of a lack of structure in descriptions of the real world. The creation of a cohesive set of definitions can provide the structure. For example, if we want to find out if all Christians know the Bible, then the main methodological problem is going to be deciding what Christians are (People who say they are? People who go to church regularly?) ”

“ Value statements Value statements include statements about personal tastes, such as "all of Shakespeare's plays are rubbish", and moral statements, such as "everyone ought to give to charity". Value statements can be distinguished from factual statements by a number of logical and epistemological properties. Evidence can be used to support or falsify factual statements but not value judgements. "All swans are white" is given supportive evidence by the observation of more and more white swans, and it falsified by the observation of one black swan. ”

“ Another problem is a lack of flexibility. The model building process is unable to draw upon a large body of generally accepted facts. There is, however, another theoretical possibility and that is to integrate the definitions and inductive hypotheses to form a mixed model.
Possibility of a mixed model A mixed model could expressed entirely in universals and combine the linguistic capabilities of SSM with the empirical grounding of Multiview. Care would need to be taken to distinguish between definitions and inductive hypotheses. This could be accomplished using model logic. ”

“ It is not until we add a particular statement that there is any commitment to existence. That is why is called the existential quantifier. In the argument above, existential commitment begins with , the fact that there has been at least one patient who has been discharged. ”

“ The same can be said about values; if a change in values does not indicate a change in behavior in response to some actual or potential event in the real world, then it is pointless to say that there has been any change in values. ”

“ If the information input/outputs are notional we still have to establish that they can map on to the real world. If they are real world information input/outputs between real world activities, where did the real world activities come from? ”

“ Detail abstracted from a Multiview model The limitations of Multiview There are two possible ways in which Multiview can work. One is where the stake-holders already have a well defined common language. ”

“ Therefore, provisionally at least, we can take it that the SSM models are not logical in sense 6. and that the Multiview Conceptual Models are a different type of thing.
Probert's argues that the arrows in the SSM models cannot be logical in sense 1. because the contents of the bubbles are imperatives, and logical relationships in sense 1. can only hold between declaratives. "Discharge patient" is a command and standard logics only operate on statements or propositions. ”