The Logic of Design

CIS548

The Basic Triad

Conception :: An idea is conceived in the mind.  Both logos and telos are involved, almost in a chicken/egg fashion.  For example, a software product is to be produced.  This product is to achieve a certain goal.  Following Federick Brooks and Alan Cooper, the purpose of the product is to help the user meet his/her goals.  Thus, the initial step is for the designer to ascertain and grasp conceptually what the user’s goal(s) is (are).  Which means that there is a prior goal – one prior to the designer’s goal.  The designer has the goal of making a good product.  But prior to that are the goals of the persons for whom the product is to be constructed.  Those goals become the engine that drives the design process.

The issues of goal-oriented design are addressed in Cooper’s Inmates and Brooks’ Mythical Man-Month.  And they are also central to the work of the HCI community, especially the usability focus of Nielsen and Tognazzini. 

The concept of teleios is more subtle.  Its fundamental meaning is the achievement of a goal.  Thus, it is the fitting endpoint of the logos-telos-teleios triad.  It carries an important harmonic overtone of meaning – completion.  This leads to two important points.  First, completion brings with it the idea of oneness, of wholeness.  A hodgepodge thrown together with scaffolding still present is not complete (see discussion on Ironic as an architectural style).  As in the architecture of edifices, the ultimate test of design is from the experience of the persons who live and work within that edifice.

The second important aspect of completeness is not widely recognized.  That is dependability.  This issue is so deeply ingrained in our national consciousness that it comes to mind only when the principle of created dependency is violated, as in the recent collapse of the bridge in Minneapolis.  Although the societal and legal aspects of created dependency are better understood with respect to traditional areas of engineering, the time has now come for these issues to be addressed and codified with respect to hardware and software systems.  And that will be done over the coming decade.  In the meantime we as computer scientists must recognize that completeness has not been achieved without dependability.