Engineering from reflective practice - Springer Link

Res Eng Des (t992) 4:13-22

Research in Engineering Design Theory, Applications, and Concurrent Engineering @ 1992 Springer-Vedag New York Inc.

Engineering from Reflective Practice D.I. B l o c k l e y Department of Civil Engineering, University of Bristol, Bristol, UK

Abstract. Some ideas for a new epistemology, encompassing practical action, based on the concept of reflective practice, are presented. The term reflective practitioner was first suggested by Schon (1983) in an analysis of the need to define the nature of practical competence. The prevailing culture of technical rationality, which depends on science for it rigor, is compared with that of the "wise engineer" promoted by Elms (1989). Worldview, quality, systems thinking, and responsibility are discussed as preliminaries to an analysis of reflective practice. The model is based on the passing of hierarchically structured sets of message patterns from perception to reflection to action. Intelligence is defined as an ability to construct, evaluate, and act on alternative scenarios of the future in the reflective phase. Design involves the construction of scenarios where imagined artifacts operate to achieve predefined needs for some defined person(s). Rigor for the reflective practitioner stems from the achieving of appropriate objectives. The similarities and differences between science and engineering become apparent when both are viewed as examples of reflective practice.

1

Introduction

In order to understand better the nature of engineering design I will argue that there is a need for a new epistemology o f practical action. Some preliminary ideas are presented based on the idea of "reflective practice". Culture will have an underlying role. By culture I mean the systems of agreed upon meanings that serve as recipes, or guidelines, for behavior in any particular society. An "agreed u p o n " meaning is equivalent to a symbol since a symbol is something the meaning of which is bestowed upon it by those who use it (Barrett t991). Symbols, in the form of words or Sounds of natural or formal languages, are the means through which we express knowledge. It is clear therefore that knowledge is

Offprint request: Department of Civil Engineering, University of Bristol, Bristol BS8 1TR, UK

not value-free nor is it ever complete (Blockley 1989). Engineers when using their professional knowledge are therefore faced with value judgements. They take responsibility for decisions, but what can society expect of them? I will argue that the ideas of systems engineering currently form the best approach to engineering design.

2

Reflective Practice

The term reflective practice was first introduced by Schon (1983) in a discussion concerning the role of professionals and the need to define the nature of practical competence. He was concerned with questions such as: What is the prevailing culture of the professions? To what extent is there rigor in professional practice? Why is it that professionals often seem to know more than they can articulate (i.e., have tacit knowledge)? Is there a crisis of confidence in the professions? So to what extent is there rigor in professional practice? In m o d e r n times the culture of most professions is largely formed through the education and training their practitioners receive at university. Schon pointed out that universities are, for the most part, committed to a particular epistemology which he called " t e c h n i c a l rationality." This he defined as instrumental problem solving made rigorous by the application of scientific theory and technique. He maintained that the professions have paid a heavy intellectual price for being successfully incorporated, o v e r the last century, into the universities. He quotes T h o r s t e n Veblen (1918) "The universities have a higher mission to 'fit men for a life of science and scholarship; and they are accordingly concerned with such discipline only as they will give efficiency in the pursuit of knowledge' whereas the lower schools are occupied with 'instilling such knowledge and habits as will make their pupils fit citizens of the world in whatever position in the fabric of workday life they may fall."

t4

BIockley: Engineering from Reflective Practice

Technical rationality is embedded in our institutional context, it governs our understanding of the relationship between research and practice, it forms the norms of the curriculum of professional education. By this culture researchers are supposed to supply the basic and applied science from which the techniques for practical problem solving are derived. The researchers' role is therefore considered to be superior because it is perceived as being more rigorous. The rule is that rigorous basic and applied science comes first, followed secondly by the tess rigorous skills required to apply that knowledge to real world practice. Notice that these skills are considered secondary, in fact there is often an implication that they are not knowledge at all. So what is the problem with our present culture? Schon maintains that there is a crisis of confidence in the professions. Consider three examples where the trust of lay people in experts has been damaged. Firstly, there have been financial scandals where people in the city have used their specialist knowledge and positions for personal gain; that is perceived as a question of ethics. Secondly, there have been a number of technological disasters, such as Three Mile Island and the Challenger, which illustrate that even technical experts can get things wrong; that is perceived as a question' of technical competence. Thirdly, almost everyday the newspapers report disagreements between experts about the causes of some difficult phenomena, such as the causes of heart disease or food poisoning. In court expert witnesses disagree about technical issues, for example, concerning the effects of environmental pollution; these are perceived as questions concerning the limits to the extent of our knowledge. In a culture where science is supposed to provide all of the answers, the iayperson can be forgiven for being rather confused and for losing confidence in the professionals. A consequence is that there is now an increased questioning of the rights and freedoms of professionals. Their license to determine who shall be allowed to practice is rooted in deeper questions of professional claims to have "extraordinary knowledge" and this depends on our understanding of the nature of knowledge and its relationship with practical competence. Practitioners know more than they can articulate, this has been called tacit knowledge (Polanyi 1958). Schon attempted to analyze the capacity that practitioners often reveal, of being able to reflect through intuitive knowing and of using this capacity to cope with unique, uncertain, and conflicting situations. Later in the paper an alternative conceptual framework for this will be presented.

Science, it is often argued, is objective and valuefree. By contrast practitioners are frequently embroiled in conflicts of values, goals, purposes, and interests. For example, a central difficulty in engineering design is the balance between safety and cost. Thus, any consideration of practical action must face up to the need to define a value system. Schon also identified the need to recognize that professionals deal not just with problems but rather with problem situations. He argued that complex systems are sets of interacting problems that he called " m e s s e s . " He maintained that professionals do not solve problems they manage "messes." The failure of the algorithmic approaches to practical problem-solving, as for example in Operational Research, is because such approaches fail to help with the formulation of problems from out of the " m e s s . " The scientific approach is to isolate parts of a problem " m e s s " by selective inattention until a clear statement of a difficulty can be addressed rigorously. This provides a major dilemma for the professional because the selective inattention of the scientist may in fact have excluded important aspects of the original problem that cannot be ignored. The professional then relies on what Schon defines as "reflection in a c t i o n " w t h e kind of knowing inherent in intelligent action. Skillful action depends upon more than the practitioner can articulate. The question then is whether these skills are in any sense inferior to the rigor of the scientific approach. The model of reflective practice to be presented will shed light on this question.

3

Wisdom Engineering?

Elms (1989) has argued that engineering education tends, for the most part, to concentrate on the giving of knowledge (rather like the pouring of water into a jug!). He argued that knowledge alone does not give capability. An engineer must necessarily be technically competent and clearly knowledge is part of that. However, there are people with a great deal of knowledge but who are not good engineers. Capability is something more stable, more endurable than knowledge, but which tends to be acquired almost incidentally as a byproduct of obtaining knowledge. Design courses perhaps are an exception as they particularly involve more than a transfer of knowledge. However, many people have argued that these skills cannot (should not) be taught in a University since they rely on personal skills and require the incentive of real responsibility. Elms argues that one of the most fundamental reasons why engineering capability is not taught is that the very

Blockley: Engineering from Reflective Practice

nature of engineering is poorly understood. He sees it as fundamentally different from science, since science is truth-oriented and engineering is goal-oriented. Science uses words such as true/false whereas engineers are concerned with the quality of a solution such as " g o o d , " " b a d , " "better," "worse." Engineering researchers are more likely to be involved with " h o w " to do something rather than whether something is true or false. At a very fundamental level the very discipline of philosophy is concerned with knowledge and its methodology is aligned with mathematics and science and that perhaps is why it is inappropriate for engineering. Elms quotes Maxwell (1984), who was concerned with what he saw as the basic flaw in the scientific method which is that it deals only with what is true/ false and appears not to care about the use of knowledge for good or ill. Such a lack has obvious ethical implications and may indeed be a major cause of some of the major ills of the world. Maxwell argued that scientific knowledge was being neither produced nor used responsibly if it were regarded as being independent of any values. Maxwell proposed a philosophy of wisdom which is a combination of knowledge and values. Elms argues that wisdom is more than a matter of action and good decision-making. Rather it is a quality of the way of looking at things; it is the ability to see the world clearly in a coherent picture. This clarity is simple but not simplistic and depends upon strong underlying conceptual models of the world. Elms sums up his ideas as follows: " a wise person has to have knowledge, ethicalness and appropriate skills to a high degree. There also has to be an appropriate attitude; an ability to cut through complexity and to see the goals, the aims, the fundamental essentials in a problem situation, and to have the will and purpose to keep these clearly in focus. It is to do with finding simplicity in complexity. More fundamentally it is to do with world views and the way wise persons construct the world in which they operate; which is to say, in engineering, that wisdom is to do with having appropriate conceptual models to fit the situation."

4 Incompleteness Is there a dilemma of a choice between rigor and relevance, the resolution of which requires the skills of a wise engineer? In the search for improvement by introducing some' rigor, the practitioners " m e s s " can be analyzed and particular difficulties cut down to manageable proportions by a process of

15

selective inattention as mentioned earlier. This scientific approach is reductionist, it selects only part of the totality for consideration. Of course this approach has been spectacularly successful, the whole history of physical science has been built upon it, but nevertheless it must not be confused with the difficulties of dealing with the original " m e s s . " In fact it has been singularly unsuccessful in dealing with the social sciences where the problems are distinctly more " m e s s y . " Certainly the assumption should be challenged that science should be considered to be a superior exercise simply because it is more rigorous. It is in fact, often a simpler (but not simple) execise because the number of interactions in the problem set are much reduced. The central problem in the dilemma is that although the process of selective inattention may result in sets of simpler problems which can be tackled rigorously, each one may be so unlike the original " m e s s " that they are barely relevant. There is therefore indeed a dilemma of rigor or relevance for the practitioner and the resolution of the dilemma requires wise counsel. However, the dilemma is only a dilemma in terms of the search for truth. The rigor in practical problem-solving is obtained through the determination to achieve objectives and this can be just as intellectually challenging. But even when a problem has been sharply defined and solved scientifically there are still fundamental problems of incompleteness. The population of possible future events is infinite, since as Plato noted, " H o w can we know what we do not know?" The problems of the incompleteness of scientific and mathematical knowledge and its relationship with engineering have been discussed previously (Blockley 1980, 1989). The theorems of Godel define the limits to mathematics, the Uncertainty Principle defines the limits to physics, and the recent discoveries of deterministic chaos demonstrate that even simple systems can behave in a complex manner. Two kinds of models have been distinguished. The first is a closed world model which represents total knowledge about a problem and in which every thing is true or false and no undefined or inconsistent states are possible. In a closed world the information is complete in that all and only the relationships that can possibly hold among the concepts are those implied by the given information. The models of classical science are of the closed world type. In an open world a concept may be true, false, unknown, or inconsistent with all degrees of uncertainty in between; these, of course, are the real world problems of engineering. In the world of technical rationality inconsistencies are forbidden. However, in practical problems the finding and set-

16


tling of inconsistencies is an important element in the problem formulation and solution process.

5

Need for Theory of Practical Competence

Thus, there is a need for an epistemology which encompasses practical action. Such a theory should not "throw the baby out with the bathwater" and reject the philosophy of technical rationality but rather it should unify it with practical action. In other words a theory of practical action should encompass " p u r e , " "applied," and "practical" approaches; it should cover both the closing down, judgmental skills of analysis, and the opening out, creative skills of synthesis. The theory should develop new ideas about intellectual thought and practice. The ideas presented here are an attempt to begin the search for such a unifying theory. We begin with some preliminaries which examine how each of us " s e e s " the world, what we are trying to achieve, how we approach problem-solving rigorously, and how we handle the consequences of our actions.

6

6.1

Some Preliminaries

Worldview

Everything that we think and do depends upon our point of view, it depends upon the way in which we look at the world. In philosophy this is called the "Weltanschauung" (Avison and Fitzgerald 1988). We attribute meaning to something by interpreting it in the light of our experience and education. However, as social anthropologists would point out and as discussed above, our worldview is also formed through the culture of the society in which we live. Within our western culture, however, the same issue will tend to be formulated, for example, as an economic problem by an economist, as a technical problem by an engineer, and as an organizational problem by a sociologist. Each wortdview may be valid in that it may be internally consistent and that propositions deduced from it may correspond with the perceived facts. In considering how these worldviews are formed, it is useful to have some sort of model of the processes of the brain which we can characterize as follows. When we perceive something, a set of messages are sent to the brain from our sense organs. The mind organizes these messages into patterns, the nature of which need not concern us directly for this purpose, and these patterns form the software of our brains. A simple model of recog-

nition is that all that is required is a strong enough message to trigger an existing pattern and the mind then follows it. The purpose of thinking is to find patterns and, of course, it is possible to lock into the wrong pattern. Learning is the relating of new patterns to existing patterns. Creativity is the linking of patterns not previously linked. Some patterns may be genetically inherited and therefore part of the "hardware," the patterns we share with our parents. A large repertoire of patterns derives from a rich set of experiences and thinking is then much more powerful. A danger is that a small set of patterns results in intolerance and a lack of imagination. Two people will tend to share the same worldview if they come from similar cultural, social, and educational backgrounds. In summary, we can imagine a person's worldview as a set of patterns laid down in the brain.

6.2

Quality

The objective of a reflective practitioner is to produce "something" with specific qualities. The "something" will have an objective existence, such as the expression of a theory in natural or formal language or it could be a physical artifact such as a bridge. However, the meaning of that objective existence, the interpretation of that existence, will depend on the person's worldview expressed in terms of qualities. The word quality has at least two meanings. The first is as a degree of excellence and the second is as a trait or characteristic. The reflective practitioner is interested in setting and reaching goals. The quality of excellence is achieved through the setting and achieving of difficult goals. The idea that excellence can only be achieved through the search for truth is partial, since it is only the case when that is indeed the goal (as for example is usually understood to be the purpose of academic research). The concept of "appropriateness" is more important than truth since many objectives may be reached without knowing, or being centrally concerned with, what is actually true. Of course the reflective practitioner is interested in truth but his or her objective is to set "appropriate goals" and to be rigorous in his or her determination to achieve them. The goals are defined in terms of appropriate levels of attainment of required traits or qualities. The more easily measurable are the goals, the more easily it is determinable that they have been reached. Thus, the rigor of science and technical rationality is included in this analysis if truth is the goal--but other goals may be more appropriate in other situations.


6.3

17

Systems

" S y s t e m s " is a modish word, but what does it actually mean? It really is itself a subject in which one can think and talk about other subjects, it is a metadiscipline whose subject matter can come from virtually any other discipline. Thus, it is more of an approach than a topic; a way of going about tackling a problem. In simple terms a systems approach is one which takes a broad view, which tries to take into account all aspects and which concentrates on the interactions between different parts of the problem. The scientific approach characterizes the world by assuming that natural phenomena are ordered, regular, and not capricious and it is reductionist so that problems are broken down into their constituent parts and tackled. Systems thinking alternatively questions the assumption that the component parts are the same when separated out as when they are part of the whole. For more discussion of the systems approach see Checkland (1981). It is obvious that whole systems have characteristics that the subsystems do not have. F o r example, a human being is made up of subsystems (nervous system, skeleton, etc.) and none of them are able to walk about for that is a characteristic of the human being. The term holon was coined by Koestler (1967) to describe the idea of something which is both a whole and a part. Thus, a human is a holon in that a human is a whole (with a set of subsystems) and a part (of a higher o r d e r systems, such as family and other societal groupings). The reflective practitioner is, in the terms of Elms, a wise engineer and a systems thinker.

Fig. 1. The reflective practice loop.

lem-sotving processes. In overview the problemsolving loop is simply this: we perceive the state of the world (the senses) as sets of patterns in the brain (these patterns may be chemical, electrical, biological, etc., it matters not for the purposes of this discussion), we interpret our perceptions (think/reflect), we act upon the world (behave), and finally we perceive a new state o f the world. The RP loop is (Fig. 1):

6.4 Responsibility world --~ sense ~ think (mind) --~ act ~ world The concept of responsibility is central to the role of the reflective practitioner. The RP is aware of the limitations of his knowledge and skills and is very much aware also of the duties owed both to clients and to the general public. Thus the RP is not concerned principally with the degree of truth of a theory or model, rather the RP is concerned with the taking of responsibility to act on the basis of the theory or model. The taking of responsibility im-plies not that one has earned the right to be right or nearly right but that one has taken precautions that one can reasonably be expected to take against being wrong (Blocktey 1985).

7.

The Model of Reflectiqe Practice

We will represent all human activities in terms of a hierarchically structured set o f evolutionary prob-

In other words: world ~ perception --~ reflection --~ action ~ world Needs are patterns which may be in-built or learned. Problems are the result of mismatching patterns. The world changes through our actions, we have a new set o f perceptions and the loop is repeated. Our attention is the focus of our perception and is controlled by the very processes of a hierarchically structured set of problem-solving loops at differing levels of definition (see Fig. 2) all occurring in parallel. In mathematical terms, mind is a many-to-many functional mapping from perception to action. We can imagine this mapping as a relation which could be a set of functions or a set of rules.

t8

Blocktey: Engineering from Reflective Practice

t _.~_ou~.

Ea E~

=~

Time

Physical World Key :

multiple communication channel (parallel) Perception ( ~ ) Reflection Action

Fig. 2. Hierarchically structured reflective practice loops.

In our subconscious mind this mapping from sensory perception to action is determined but not necessarily determinate. Some of these mappings define skills which may be innate (e.g., musical) and some which are learned (e.g., playing a piano). The mind receives signals from sense organs and sends out signals to various parts of our body. For example our body temperature control mechanism is of this type. Language is the result of linkages between patterns of perceptions and patterns of audible sounds (phonemes) and visible marks or symbols (marks such as numbers, letters). These linkages are themselves patterns. Learning is the development of new patterns and new linkages between patterns. It is an evolutionary problem-solving process central to the building of the mind. We can postulate that clusters of patterns can be linked to word patterns to form higher level, more general words or concepts. We can imagine these concepts are linked hierarchically. Linkages between higher level concepts may also be clustered to form relationships. Mental models are patterns representing concepts and relations. Language is learned from the base of the subconscious mind by a learning process. Our conscious mind is the result of the formation of mental models expressed in terms of language. Through language we can express ideas about ourselves (identity) and about our own knowledge (high-level reflection).

Through language we reflect and act on the world in a conscious evolutionary learning problem-solving process. Memories are patterns in the mind and through those which are stored in our conscious mind we have concepts of time and identity~ Imagination and creative thinking is the result of forming links between memory patterns which were not previously linked. Scenarios are temporally ordered sequences of events. Through imagination we can build scenarios which have not actually happened both about the past and about the future. Note however that these links are made between existing patterns in the mind. The richness of alternative future scenarios must therefore depend on the richness of past experience. Knowledge is a set of mental models. Some mental models cannot be expressed in natural or formal language and these are part of, but do not define, the subconscious mind (e.g., the rules controlling heart beat). Mental models that can be expressed in natural or formal language are part of, but do not define, the conscious mind. Some models can be subconscious some of the time and conscious at other time (e.g., learned skills such as driving), and some are almost entirely conscious (e.g., speech). Conscious problem-solving is an evolutionary process where actions are taken on the basis of an evaluation of alternative scenarios, which is reflection. Evolution derives from learning.


Consciousness is attributed to an organism when it shows intelligence. I define intelligence as an ability to construct, evaluate, and act on alternative scenarios of the future. The richer the ability to construct scenarios the more intelligent we suppose the organism. Notice that by this definition intelligence also includes action. Penrose (1990) quotes Konrad Lorentz describing a chimpanzee in a room which contains a banana suspended from the ceiling just out of reach, and a box elsewhere in the room: "The matter gave him no peace, and he returned to it again. Then suddenly--and there is no other way to describe it--his previously gloomy face 'lit up'. His eyes now moved from the banana to the empty space beneath it on the ground, from this to the box, then back to the space, and from there to the banana. The next moment he gave a cry of joy, and somersaulted over to the box in sheer high spirits. Completely assured of his success, he pushed the box below the banana. No man watching him could doubt the existence of a genuine 'aha' experience in anthropoid apes." The conscious mind has the ability to build scenarios, hence to make choices to best satisfy needs in a set of reflective practice loops. Thus, by this interpretation, the chimpanzee is indeed in possession of a conscious mind. However, the mind is primitive and is unable to form the patterns necessary for written or spoken language, although some animals are able to use sign languge. Thus, a central characteristic of intelligence is the ability to construct scenarios which include the use of tools to manipulate objects in the world. It involves the ability to construct scenarios in which artifacts already in the world are manipulated to enable the organism to achieve its needs (such as food in the case of the chimpanzee). The next level of intelligent behavior is the ability to make a tool or artifact. This is accomplished by perceiving the world, imagining alternative scenarios, and evaluating and choosing one of them (i.e., design) and then taking action to change the world (i.e., manufacture) so that the chosen scenario is realized. At this level the chimpanzee would have in some way to see that the box must be altered before it is suitable for standing on to reach the banana. Further, at an even higher level, the chimpanzee would have to be able to conceive the nature of the box and be able to manufacture it from some available timber. Tools are artifacts which extend the capabilities of human beings and the 'whole of our activity is based on this ability. Human beings are comparatively weak, compared with some other animals,

19

when faced with dealing with the natural world without the use of tools. Thus to fulfill a basic need such as food, early man used primitive tools. As men were able to satisfy basic needs, higher level needs (as expressed for example by Maslow's hierarchy of needs) became important too. In the modern western world people pursue top-level goals, such as self-actualization, because the basic needs, such as food and safety, are relatively easily satisfied. The need to explain and understand our world is also a high-level need. In the history of human development as our understanding has increased so we have been able to develop more sophisticated tools. Thus, the evolution of science has been intimately bound up with practical action. As a simple example the tool most basic to science is a rule for measuring length; of course measurement is the basis of the physical sciences. The history of science and engineering are therefore intimately interwoven and interconnected. Better tools mean more understanding which in turn enables the production of better tools. Modern tools are complex systems of artifacts, such as computers, but also include cars and airplanes, buildings, and power stations; in fact all products of practical endeavor (i.e., engineering). Modern nuclear physics, for example, is entirely dependent on the engineering of vast particle accelerators. Although engineers apply science they are not applied scientists;just as scientists use engineering but are not "pure engineers." It is clear that design is central to human activity. Design is the construction of scenarios where imagined artifacts operate to achieve predefined needs for some defined person(s). It is limited only by the imagination of the designer. It involves the creative linkage of patterns of concepts to form new relationships. It involves the analytical, judgemental evaluation of these creations against clear criteria. Thus, the reflection phase in the model of the reflective practitioner becomes increasingly sophisticated as we move from the use of tools through to the design and manufacture of tools, which is engineering.

8 Problem-Solving The usual characterization of the problem-solving loop is of the form problem -+ collect information -+ find alternative solutions -+ evaluate alternatives -~ select an alternative -+ implement solution --+ follow up consequences -+ review situation -+ new problem.

20


In terms of the model of reflective practice this characterization is a partial high-level model. All aspects of this characterization are included in the reflective practice model of Fig. 1. The first part is contained in the reflective phase, the implementation phase corresponds to action, and the follow-up consequences and review are themselves lower level reflective practice loops. The importance of perception and hence worldview is not captured and the essential integration of perception, reflection, and action missed.

9

Science and Engineering

In order to clarify further the interpretation of professional activities using the reflective practice model, we can now examine the relationship between science and engineering in terms of the model. The first step is to clarify objectives. What needs are being fulfilled? The objective of science is to produce knowledge which has specific qualities (truth, explanation, prediction, etc.). The need is to understand. The objective of engineering is to produce artifacts which have specific qualities (safety, function, form, etc.). The need is to operate on the world, which in turn may be driven by several needs, for example, to feed, to protect personal safety, to understand. Table 1 is an attempt to capture and compare the qualities of engineering and science. The qualities are grouped into the central headings of function, form, grounding, specification, etc. The qualities in the first and third columns are those usually listed in discussions of these matters. Notice however that they are not mutually exclusive. For example, a scientific theory may be fit for its purpose if the purpose is to predict and explain. Similarly, a scientific theory will be appropriate if being appropriate in science means being precise and clear. Perhaps the most difficult comparison in Table 1 is that concerning the quality of "grounding." Clearly, science is grounded on truth, the whole basis of science is the search for truth. (Here I use the correspondence theory of truth, see Table 2.) However, the concept of a true artifact is meaningless; engineers are interested in truth only to the extent that it enables them to produce artifacts that have the requisite qualities. The hypothesis presented here is that an artifact is grounded on safety. Table 2 presents some comparative definitions of terms in science and engineering. The term calculation procedure model was coined by Blocktey and Henderson (1980) in an attempt to capture the com-

Table 1. A categorization of the qualities of scientific and engineering knowledge

Scientific knowledge

Engineering knowledge

Quality

Prediction Explanation Simplicity Elegance