2.3 THE SEMIOTICS OF ENGINEERING DESIGN
A distinction between the use of absolute categories within artificial intelligence as a fundamental cognitive model of the world and categorization as a cognitive capacity of humans is made by S. Newton [Newton 92]. In a computable model of cognition, categories are templates or prototypes, existing as entities somewhere. The alternative to the formalist ontology is that of a human-centered, hermeneutic ontology where experience is primary and categorization neither absolute nor predefined. In Newton's alternative to the computational metaphor for human cognition, a communications metaphor using coordinated speech acts is detailed. Categorization, particularly involving coordinated speech acts, emerges not so much to model the world as to facilitate the computer's use as a medium for the exchange of expressions.
Hermeneutics is the study of interpretation. A model, however objectively the model's creator attempts to imbue a given meaning, is subject to interpretation by other agents, whether these agents be human or computer-based. How well the original meaning is conveyed, that is how well the meaning of the interpreted model matches the original meaning, is a communications problem as opposed to a computation problem. Peter Wegner explores paradigms of modeling in terms of interpretation, where the meaning of a model is subject to agent-specific interpretation [Wegner 91]. Translation, as between design representations, it is noted, is a particular form of interpretation and the hermeneutic nature does not solely involve human agents.
Richard Buchanan argues that graphic design should be approached in terms of persuasive argumentation, where the images and words are directed toward an audience actively involved in creating their own interpretation [Buchanan 92]. Like that of critical theory, both agents are aware of each other through the design artifact. While there is not necessary direct feed-back from the audience, the focus on the part of the designer is that of influencing the audience rather than asserting a take-it-or-leave-it approach to the engineering, whereupon a correct interpretation is at risk.
This conceptual repositioning of the design from passive artifact from computation to and active communicative medium must be considered in terms of what Buchanan calls "placements". Unlike categories, placements are temporary views or reconstructions of a given model. Like metaphors, a model is viewed in terms of another. New perspectives and possibilities develop. (There is danger, it is noted, that these placements or metaphors can become ossified into categories; the freshness is lost for novel insight and discovery and becomes another working paradigm.)
John Searle's view of metaphors in [Searle 79] could influence the construction and nature of evaluation agents. The recipient of the metaphorical utterance must actively contribute to the communication by making the connections between the two models, accessing one model in terms of the semantic content of the other. For example, the metaphor of a "design processor" may invoke the meanings of word processor or food processor and the consequent mechanical deconstruction and manipulation of words or food in terms of design. The metaphor of design processor involves a more active (and powerful) involvement on the recipient's part to interpret the metaphor than a brief description of an artifact-centered design system.
Metaphors, placements, and categories can be considered as various degrees of interpretive frames semioticians refer to as "myth". A myth is not construed here as fanciful or untrue (although it may actually be by some interpretations). Rather, a myth is defined as a code that informs an entire structure of beliefs [Solomon 88].
As described by de Neufville, American myths such as the Horatio Alger ideal of the hard-working, rugged individualist pulling himself up by his bootstraps to inevitable riches influences basic public policy in the provision for equal opportunity and the disdain for public assistance. Other myths include Thomas Jefferson's ideal of the responsible, yeoman farmer, who owns a sufficient amount of land to support himself and his family. This myth informs and influences the American Dream of owning one's own home, with subsequent expectation of government support in the form of income tax mortgage reductions.