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Robust Engineering Methodology: Part One

By Joseph S. Bobinis

This series explores the relationships of methodology for robust engineering and the possible effects of that method in order to accelerate the evolution of systems. The goals are to determine how systems evolve or progress; the principles involved in that progression and; whether robust engineering methods can influence those engineering principles toward evolution and progress. The following is PartOne of a three part series.

Teleology (Greek: telos: end, purpose) is the philosophical study of design and purpose. A teleological school of thought is one that holds all things to be designed for or directed toward a final result, there is an inherent purpose or final cause for all that exists.

The engineering enterprise is teleological; the concept of quality can be an evaluation of how efficiently that teleological end state is achieved. Also important is how quality is considered a process for measuring non-contradiction or identity (between possibility and actuality) in an engineering enterprise.”And even today, to switch fields once more, part of our difficulty in seeing the profound differences between science and technology must relate to the fact that progress is an obvious attribute of both fields.”1

The Nature of Engineering Progress (Teleology)

In his book, Invention by Design How Engineers Get from Thought to Thing, civil engineering professor, Henry Petroski characterizes the difference between science and engineering as follows: “The idea of design and development is what most distinguishes engineering from science, which concerns itself principally with understanding the world as it is.”2 But he also states that engineers are confined to those laws of science; that engineering is an enterprise, it is the ability to work inside those natural laws to control the variability in nature for purposive artifacts. Petroski uses numerous case studies as a heuristic method to describe how engineering and its artifacts progress.

The difference between science and engineering for Petroski is that nature may not be teleological, but engineering is. Arguably, this is obvious since an individual can point to the end state of an engineered system by examining the articulated requirements while following them as they are decomposed and allocated in the classic “waterfall method,” to functions, uses and physical components.

Along with the laws of nature other impediments (problems) faced by the engineering design process can be framed in a more pragmatic context. The influences of those things considered external to the system – design boundaries. “In fact, no artifact or system that any engineer designs or analyzes can function independent of a larger social system and the best designers and analysts are those who are constantly aware of the interrelations of all things.”3

Petroski’s last statement seems more metaphysical than pragmatic and it seems contradictory to his previous position. If the design activity is teleological and articulated from the start of the activity, why must designers be aware of anything else but the “requirements” (end state)?

Petroski provides an insight into how engineered systems evolve and is fundamental to understanding what qualifies a system as progressing. An individual could easily quip that the only perfect system is God, but that would do little to elucidate the nature of how engineered systems progress from thought to thing.Consider “What would constitute a perfect system?” as an aim for implied engineering or system progress.

The questions that need to be asked include:

  • What is a system?
  • What are its boundaries?
  • What is its purpose?
  • How is it created?
  • What would an ideal system look like?
  • Do all systems have teleology?
  • What other forces influence the process of a system from the requirements (idea) to its instantiation (thing)?

In his paper, “The Laws of System Evolution,” TRIZ expert Vladimir Petrov tries to characterize the perfect system in order to frame the overall context in which the nature of systems can be analyzed and addressed.

Evolution of all objects of the material world including technological objects are governed by certain laws. Among them are the laws of dialectics (the law of unity; interpretation) of opposites; the law of transformation of quantity into quality; and the law of negation. Technical system evolution must have three levels:

  1. Demands
  2. Functions
  3. Systems

An absolutely ideal system (which is impossible) is defined as a system which does not exist but all possible functions are delivered at the required moment of time in the required space with 100 percent effectiveness.”4Why is a perfect system impossible? There are two parts of Petrov’s definition that make it impossible:

  1. “All possible functions” and;
  2. Space and time limitations.

An individual can deduce from this that actual systems must have a limited number of functions (boundary) and must exist within limitations of space and time (footprint and life cycle). Another key to Petrov’s definition of a perfect system is its 100 percent effectiveness. The assumption here is that the functions are translated from possibility to actuality with no loss of energy (quality) and by the mention of at “no cost.” Any variance from the intended system functions to actual system behaviors makes any system less than 100 percent effective or has a loss in quality. This expresses the teleological nature of the design process.

The Nature of Systems

Petrov provides a definition and a set of attributes that all systems possess: “Systemity, a coordinated interaction between all objects including the environment where objects are located.”

This interaction must be fully balanced. System requirements include:

  • A system must be designated to meet certain purpose.
  • A system must possess a certain structure, which provides the achievement of purpose.
  • Relationships and interactions within the system and with its super-system must provide a full balance, which means that there must be no negative effects caused by the relationships or the interactions.
  • Regularities of evolution of a given system as well as environment must be taken into account.”5

Every system must have a purpose. How does an individual determine the purpose of a system? In his paper, “Customers and Society Drive Innovation,” innovation expert Michael S. Slocum takes the position that the customer as individuals and “society as a whole” determine the purpose of a system. “The customer is in control in the buying/selling process, determining whether a product (goods or services) is acceptable or a launch failure. How are unmet needs discovered? There are various methods of identifying unmet needs – the customer is involved in some of them, but not all.”6

The primary determinant of system purpose is the customers and society in general. They define the need from which the system is designed to fulfill. But they are not the only determinates of system purpose. The designers (engineers) also have a primary role in the purpose of a system. Discovery (invention) is a function of both the need and fulfillment.
Customer requirements must be translated to functional, physical and operational behaviors of every system. Often the customer or users do not understand the loss of efficiency in this translation. “The engineer often acts as an inventor or designer in such considerations. Indeed, the engineer is often the most severe critic of existing technology and why things change over time.”7

A system must have a structure. What is system structure? System structure refers to the way the purpose or need is translated into a thing. The thing or system cannot be separated from its structure. It must have both function and structure or, as Petrov characterized it, a “working unit.” This working unit must also possess an energy source and a system of control. A system must have:

  1. Internal relationships (amongst its parts) or a working unit;
  2. External relationships (with the environment), an energy source and conversion; and
  3. Internal and external relationships that work harmoniously together (no negative effects or failure); under control.

The efficiency or quality of the system can then be determined in the following way:

  1. A system must have a well-defined purpose. Source = human.
  2. That purpose must be translated into a thing. Working unit = source = human.
  3. That working unit must have parts that work together with as little loss of energy as possible. Source = nature (materials).
  4. That working unit must also work with the environment with as little loss of energy as possible. Source = environment.
  5. The system under operation (energy conversion) must be under control through time. Source = human.

In Part Two of this three part series the author will explore the causes of system evolution.


  1. Thomas S. Kuhn. The Structure of Scientific Revolutions. University of Chicago Press, pg. 161; 1962.
  2. Henry Petroski. Invention by Design How Engineers Get from Thought to Thing. Harvard University Press, pg. 2; 1996.
  3. Henry Petroski. Invention by Design How Engineers Get from Thought to Thing. Harvard University Press, pp. 5, 6; 1996.
  4. Vladimir Petrov. The Laws of System Evolution. The TRIZ Journal, March 2002, pp. 1, 5
  5. Vladimir Petrov. The Laws of System Evolution. The TRIZ Journal, March 2002, pg. 3.
  6. Michael S. Slocum. Customers and Society Drive Innovation. Real, pp 1, 2; 2006-2009.
  7. Henry Petroski. Invention by Design How Engineers Get from Thought to Thing. Harvard University Press, pg. 27; 1996.

About the Author:

Joseph S. Bobinis is a project management professional and has written several papers on product development, systems engineering and logisitics. He holds a B.A. in philosophy from Ithaca College. He currently specializes in Sustainment Architecture, IT architecture and engineering processes. Contact Joseph S. Bobinis at joseph.bobinis (at)