Colloquium: Functional Decomposition: On Rationality and Incommensurability

In this talk I present results of my project on functional decomposition. The main goal of my project is to explain why different models of functional decomposition are used side-by-side in engineering.
Although there are clear engineering incentives for fixing a commonly shared model, in particular to solve cross-communication problems, this project has not been taken up in general in engineering. I aim to explain why functional modeling research is defying expectations.
I advance two related explanations for the co-existence of different models of functional decomposition. The first explanation states that the choice for and suitability of particular models of functional decomposition (for a particular engineering objective) is influenced by the particulars of the design knowledge that is employed in their construction. The second explanation, which is broader than and inclusive of the first explanation, expands the Kuhnian thesis of methodological incommensurability into the engineering domain. Key to methodological incommensurability is the notion that there is no commonly shared set of standards – factors that influence the choice for a theory – available on the basis of which the choice for scientific theories can be fixed in unambiguous fashion. The core of my
second explanation states that the choice for particular models of functional decomposition is influenced by particular ‘engineering standards’ that are employed in model choice. And that these engineering standards vary (and conflict) between functional modeling accounts.
I further argue that co-existence of functional decomposition models (and its persistence) is rational. I argue that the choices to employ specific knowledge in building models of functional decomposition are plausible given the objectives for which these models are advanced. And I argue that the considered engineering standards are suitable means to achieve particular ‘engineering goals’. These engineering goals, in turn, are conducive to the objectives for which models of functional decomposition are advanced.
I close by briefly outlining a strategy for translating different models of functional decomposition that avoids cross-communication problems.