This paper proposes the study of discontinuities in design practices and theories as a useful tool in design research. Discontinuities appear to a large extent  to coincide in a single boundary. As a result, this suggests design theories be seen as two distinct realms. An implication is the need for a second, distinct body of design theory, practice and philosophy. A defining criteria of this second body of design-related knowledge is the creation of designs that are beyond individual human comprehension: a matter of human biological limitations. The paper builds on multiple elements of prior analysis by the author relating to discontinuities previously assumed to be continuous.

 Discontinuities and human bodily limits and their implications for design theory and the philosophy of design

© Dr Terence Love 2013 CEO, Love Services Pty Ltd. PO Box 226, Quinns Rocks, Western Australia 6030.

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Please cite as:  Love, T (2013) Discontinuities and human bodily limits and their implications for design theory and the philosophy of design. Perth, Western Australia: Praxis Education.


 Philosophy, Design, Theories, Discontinuities, Physiological Limitations


 The contemporary history of design methods, theory and philosophy of design may be considered as starting around the middle of the last century (Cross, 1984). In the UK, a key starting point was the conference on design methods leading to the formation of the UK’s Design Research Society (Jones & Thornley, 1963); in Europe, the establishment of the Workshop-Design-Konstruktion (WDK) group in Germany (Pahl & Beitz, 1984); and in the US, the formation of the Design Methods Group in 1967. These developments were preceded, however, by theory developments relating to design process mainly in engineering (see, e.g. Matousek, 1963) and architecture following the shifts to standards-based production in developed countries consequent on increased availability of capital and transport after the 18th century (Morton, 1938).

 One of the strengths of designers and design researchers throughout the history of design and design research, has been to address conceptually difficult problems. For designers, it has often been a matter of pride to be able to create solutions when there has been insufficient information, occasionally even arguing the ability to create designs that clients would want rather than what clients asked for. Design researchers have tackled some of the most conceptually difficult topics that involve multiple viewpoints, mixtures of science, art and subjectivity, and situations in which the term design might have several different meanings and layers of meanings. To some extent, the abilities and scope of design research has echoed the traditions of design practice in addressing difficulties.

 This paper presents a challenge in that tradition by drawing attention to two aspects of human design practice, thinking, theory and philosophy that appear thus far to have been overlooked. The first is drawing attention to the unjustified assumption that human ability to address design problems is infinite, when there is significant evidence that humans are physiologically limited in many ways in the subjective abilities involved in design activity. The second is to reconsider assumptions that aspects of design are continuous functions. This paper draws attention to analyses and evidence that suggest design is marked by discontinuities (physiological limitations being one of them). The existence of these discontinuities present a challenge to current theory and suggest the need to at least partially re-conceive aspects of design practice, theory and philosophy of design along with the methods needed for each.

 For example, in general, in literature of design methods, theory and philosophy of design it has been explicitly and tacitly assumed human design activity applies to a continuous spectrum of design outputs ranging from easy to difficult, from artistic to scientific, from valuable to not valuable, from ephemeral to timeless and so on. The assumption being these spectra are continuous and as such can be addressed by humans individually or in groups via their thinking and subjective, intuitive, emotional and creative internal abilities.

 The analyses in this paper indicate this assumption and its corollaries are misguided and instead the situation is better viewed as comprising two essentially different classes of design activity:

 1.       Designs that follow the above and can be undertaken by humans ‘in mind’ using their internal subjective, emotional, intuitive and creative expertise

 2.       Designs that are beyond human internal subjective abilities

 This is one example of a discontinuity. The paper focuses on the implications of identifying this and other discontinuities in design activities and theory making for creating design methods, practices, theories and philosophy of design. The analyses and findings presented in this paper point to a change in philosophical and theoretical foundation that accords with, and is supported by, the findings of others; such as Petroski’s work on design failures (Petroski, 2012), Forrester’s work on complex systems (Forrester, 1971, 1972, 1998), Rittel and Weber’s work on ‘wicked problems’ (Rittel, 1971, 1972a, 1972b, 1984; Rittel & Webber, 1974), Ackoff’s ‘messes’ (Ackoff, 1974, 2001) and Conklin’s ‘argument visualisation’ and ‘collaboration’ (Conklin, 2003, 2010). Significantly, the analyses of this paper also challenge those theory foundations of researchers whose findings and evidence support this paper. In essence, we are addressing the same issues yet from different perspectives and assumptions, and critical analysis that includes the evidence of discontinuities leads to different outcomes.

 In this paper, it is taken as given that human abilities are limited in ways that mean that it makes it impossible for us to do some tasks using subjective internal processes, due to physiologically-based limitations of our cognitive and related subjective emotional and intuitive facilities. This contradicts with the underlying assumptions of many researchers, theorists and practitioners that such intrinsic physiological limitations simply make it more difficult to intuit successful designs. In the literature, the means of understanding and addressing difficult design problems is conventionally allocated to thinking, feeling, intuition, emotion, creativity, collaboration, visual representation, improved communication and participatory design processes. The analyses in this paper suggest that for some classes of complex design situations, the assumption that conventional design methods are appropriate do not apply. In part, what follows is to clarify the theoretical and practical details of that boundary situation and the ways of discussing it.

 The research and findings described in this paper is driven by a simple question:

 ‘How do we develop design methods, theories and philosophies to identify the best solutions to design problems that are beyond designers’ human abilities to understand and predict the behaviours of the outcomes in mind, alone or in a group?’

 This paper brings together for the first time several partial analyses relating to discontinuities that contradict the common assumptions of smooth continuity of factors in various aspects of design practices, theories and philosophy of design. This focus on discontinuities is theoretically powerful because if a discontinuity can be identified in what was previously assumed to be a continuous function, this implies derivations based on the assumption of continuity may be erroneous, and indicates that there will be different conditions on each side of the discontinuity. For design it implies there should be different explanation, methods, practices, theories and potentially different philosophical foundations for theory on either side of the discontinuity.

 Structure of the paper

 The structure of this paper is as follows. The first section has provided an executive summary. The next, second, section explains and defines concepts used. The third section draws attention to and describes a variety of different discontinuities in design practices, theory and philosophy that contradict widely held assumptions of continuity of aspects of design practices and theory. The fourth section, draws attention to the importance of predicting the behaviour of outcomes resulting from a design revealed as part of the section on discontinuities; outlines implications for design practices, theory and philosophy of design of discontinuities, including pointing to the need to clearly differentiate between Conventional Design and Complex Design; proposes an easy to use test for identifying which side of this boundary any design problem is located; outlines a methodological structure for complex design including changes to the roles of participants and addresses sundry other implications. The paper concludes with a summary of the analyses and the implications and consequences for design theory and philosophy of design that have emerged.

Concepts and terms

This paper uses terms in specific ways with specific meanings, i.e. as a technical language. The key issues described in this section are:

  • Differentiating between outputs and outcomes following the conventions of program logic modelling for the design of interventions in social, organisational, socio-technical processes, structures, policies and strategies
  • Definitions of design-related terms

Differences between Outputs and Outcomes

 The following distinction between outputs and outcomes originates in the arena of program logic and program evaluation (Baehler, 2006; CDC, n.d.; GHD, 2010; W. K. Kellogg Foundation, 2004). Following the conventions of Program Logic Modelling:

Outputs are the direct products of an activity or program. Outputs are typically fixed rather than dynamic. That is they exist in the sense that they can be counted.

 Examples of outputs:

  • Engineering drawings are an output of a program of engineering design activity.
  • Computer software is an output of the activity of computer programming.
  • Tax changes are an output of a socio-economic program to remedy discrepancies in wealth through tax reform.
  • A design is an  output of specific design activity
  • Products are outputs of manufacturing activity defined by designs


Outcomes are epistemologically and ontologically different from outputs.  Outcomes are the consequences of the outputs of a program of activity.

 Examples of outcomes:

  • Outcomes consequent on the design output of a smartphone include changes to the way smartphone users shop, changes to how smartphone users navigate on foot and in cars etc.
  • Outcomes consequent on the designed output of new banking systems might include the loss of work of the majority of bank staff, increased concentration of power in the banking sector, increased pressure to use banks rather than cash, increased proportion of income to banks for all who are forced to use banks, and increased levels of government surveillance through banking systems.
  • The outcomes consequent on the designed output of a new hospital signage system might include reduced stress for patients and their families, reduced delays in treatment due to errors in location, reduced levels of noise, and improved hospital management.

Outcomes result from and are consequent on the actions in the world of the outputs that are the direct products of a program described above.

Outcomes are typically outside the system whose outputs cause them. This contrast with the outputs of a program which occur inside the system controlled by the program of activity that produces them.

 Outcomes are typically dynamic in nature rather than fixed. That is, the outcomes resulting from a program change over time. This is to be expected because outcomes result from interactions between the dynamically changing circumstances  and contexts outside the particular program system with the typically fixed outputs from the program. A further example is the difference between research reports (output) that describes the findings of a research program. The outcomes are the effects of that output (research report) on future theory making and research and all the subsequent extended effects across the world.

 Most commonly, clients, funders and sponsors are primarily interested in outcomes whether in Design or other programs of activity (profits, social change, change in image, increased sales, increased efficiencies, changes in influence on the world, reduced crime costs and the like). Typically, outcomes are described as part of the program inputs, and in design projects as part of the design brief. Because the immediate jurisdiction of the organisations that are funded to produce designs (e.g. design businesses or teams) is limited to the production of the design, the primary interest of designers has to date commonly been the outputs, i.e. the designs they produce, with only a hopeful link between them and the required outcomes. This has led to a disjoint between the interests of the clients, funders or sponsors and the interests of the designers that has only been addressed in the more professional design fields (usually restricted design fields such as engineering and architecture) in which designers are held responsible for the outcomes as well as the outputs.

Design definitions

The definitions of design related terms used in this paper are derived as a result of the author’s epistemologically-based analysis of several hundred definitions of design and design process. From experience they appear to offer significantly greater precision of meaning and greater utility in epistemological and ontological terms for critical analysis of design theories and philosophies than process-based definitions of the activity of design. These benefits particularly apply to analyses that cross the hundreds of design disciplines. In addition, they accord with the thrust of definitions in the engineering and other technical design fields.

A design: a specification for making or doing something.

Examples of designs include:

  • A plan
  • A manufacturing drawing
  • A circuit diagram
  • A process diagram
  • A set of instructions, including text and images, how they should be formatted, choice of paper etc. for use by printers to produce (say) a book or poster

The making or doing specified in a design may be by the person creating the design or by other means, which may include people and or technology. Designs typically specify the outputs and not the means of achieving those outputs. This is important because designs are typically actualised by other agencies than those undertaking the design activity. By specifying only the outputs, this enables completion between those ‘manufacturing’ the outputs as described in the design to find more economical or effective modes of production.

Interestingly, the intended outcomes resulting from the creation of a design and its actualisation and use in the world are often included as part of design briefs. Yet, they are not typically ever included as part of the designs from the design activity based on those design briefs. Similarly, although the real world outputs from manufacture specified by a design are evaluated as to whether the design and manufacture are successful, the evaluation and assessment of the success or failure of a design typically rarely extends to the outcomes resulting from a design.

Design activity: any activity whose purpose is to create designs as the outputs of that activity.

 Examples of design activities include:

  • Creating designs on a drawing board
  • Creating designs using semi-automated design support (Adobe, AutoCAD, design standards etc.)
  • Creating designs via a design team
  • Creating designs via participatory design processes involving combinations of designers, users, stakeholders, clients, sponsors, constituencies, legislators, administrators and others
  • Creating designs via fully-automated computer software
  • Combinations of the above

 The focus of this definition is on bounding the definition to include any activity for which the creation of designs is its primary output. This then enables the possibility to distinguish between design activities and art activities on the basis of whether the output of the program of activity is a specification for making or doing something, i.e. the basis for the ‘manufacturing’ process to create a real world outputs as specified by the design. In art, the output of the art activity is not a specification. Similarly, it allows design activities to be critically analysed to identify elements that are concomitant and perhaps contiguous with design activities but which are not essential to the creation of a design

Designer:  any person, thing, process or other that creates designs as its outputs


  • Individual designer
  • Design team
  • Software and human combination
  • Solution space search software

Discontinuities in Design Practice and Design Theory

In this section, the paper draws attention to several examples of discontinuities in design activity and theory and their implications. This introduction of the study of discontinuities contrasts with the general thrust of assumptions about design, which has more typically assumed factors as being smoothly continuous. Differences in aspects of design are considered a matter only of degree and scope. For example, in continuums between easy and difficult, artistic and scientific, coarse and fine, valuable and not valuable, ephemeral and timeless, light and dark, soft and hard, and from single design to multi-participant teams or collaborations, and single discipline to multidiscipline etc.

 This section will draw attention to discontinuities in the following areas of design commonly assumed to be continuous in nature:

  • Difficulty
  • Theory, subjectivity and objectivity
  • Decomposition
  • Outputs and outcomes
  • System complexity
  • Evaluating designs
  • Human design abilities

 This focus on discontinuities when taken together points to a single boundary of deep discontinuity.


Conventionally, it is assumed by designers, researchers and theorists that successful design solutions are always possible given the necessary design ability, resources, intuition, collaboration of stakeholders and creativity sufficient to match the difficulty of the design task. The difficulty of the design task is not regarded as a limiting factor. This perspective assumes two continuities. The first is that there is a smooth continuity from easy to very difficult. The second is an assumption of continuity in the relation between the difficulty of the design and the provision of design ability, resources, intuition, collaboration of stakeholders and creativity to address it.

The assessment of difficulty can, however, be seen in terms of four categories:

1.       Easy

2.       Difficult

3.       Apparently impossible and intrinsically possible (given sufficient resources)

4.       Apparently possible yet intrinsically impossible (regardless of resources)

 Categories 1 to 3 form a continuum. There is a discontinuity, however, between categories 3 and 4. Note, intrinsically impossible is an epistemological different class,  in that there is an epistemological gap between the absolutely most difficult thing that is intrinsically difficult but possible and something that is intrinsically impossible.  Like the donkey that was trained to work on less and less food (increasing difficulty but intrinsically possible) .Eventually it was decided the donkey should be able to work without food (intrinsically impossible)  - it died.

 This idea of a discontinuity in the realm of difficulty of design has been typically absent from much of the literature on design and design theory.

Theory, subjectivity and external reality

From experience over 30 years, it has been assumed by designers, researchers and theorists that the practice and theorising about design involves smooth continuous relations between the subjective thoughts, feelings, emotions and intuitions of a designer with the expression of the design on paper or electronically and its actualisation as a physical product. Similarly, for researchers and theorists, there is an assumption of a continuum of relation between the subjective understanding of a situation, its expression as a theory, and the reality that the theory represents.

This relationship between subjective issues, theory and external reality is however fundamentally discontinuous (Popper, 1976). The three phenomena exist as three incommensurate worlds:

  • World of subjective experiences
  • World of theory
  • World of external reality

 Popper (1976) described why and how observation in any one of these worlds  is not provable by observation in any other. For example, subjective experience cannot be proven by a theory or by external observation. Similarly for the other world relations.

The uncritically adopted assumption of a smooth interconnected justification between events in the three worlds is also echoed by conflation of reasoning in which lack of information, lack of skill, and practical difficulties are regarded as a continuum of explanation about why something cannot be achieved, rather than, as in reality, discontinuous, incommensurably different, causes.

 These discontinuities, where have been widely assumed continuity, have implications for philosophy of design in discussing issues of design practice and theory across all three subjective, theory and external worlds. This issue has not yet been widely well addressed in the literatures of design and philosophy of design.


Conventionally, it is often explicitly or implicitly assumed that all design situations are intrinsically decomposable and can be addressed in smaller chunks and by multiple participants. It is this assumption of decomposability that is a foundation of design methods and theories involving collaboration (Alexander, 1964; Crabtree, 2003; Grinter, 1998; Marshall, 2011). In essence, the assumption that multiple people can contribute to a design presumes different aspects of a design situation as seen by different individuals can be combined together as a whole. Essential to this being valid is the assumption that the design situation is one that can be decomposed into the different perspectives and then recomposed. The reality is that not all design situations can be decomposed (Alexander, 1964).

There are three dimensions to decomposition of design situations:

1.       Decomposition dependent on orthogonality of relationships between elements of a design, or design situation. If the relationships between aspects are orthogonal, changing one doesn’t automatically require changes to the other as a result. Sometimes this is called sub-system independence.

2.       Many situations are conceptualised and discussed following in a general way the perspective of first and second-order predicate logic. This appears to be in part at least because many attempts to formalise descriptions in natural language naturally flow into this format. Often these descriptions, which are not necessarily accurate, follow the classic associative, distributive, and commutative relations and are hence decomposable, do not contain feedback loops and can be broken into parts that are independently addressable. Such systems are time invariant systems (see, e.g., Oppenheim, 2011)

3.       Some situations are not decomposable, they have to be addressed as a whole

Items 1 and 2 form a continuum. There are discontinuities, however, between items 1 and 3, and 2 and 3.

These discontinuities have implications for design practice and theory relating to design situations that are larger than can be addressed by a single person and yet are not decomposable.

‘Outputs’ and ‘Outcomes’

 Conventionally, it is assumed the final product of a design activity is a design. As described earlier, a design is typically a description, or more formally a specification, for manufacturing or doing something. In program logic modelling terms as described earlier, the design is the output of the program of design activity. Sponsors, funders or clients of a program of design activity are, however, typically more interested in the outcomes that result overtime from the design.

 The output (design) is a fixed thing. It exists as a single time independent entity. In contrast, the outcomes, which are the primary reason the output (design) was created, change dynamically over time because they result from the interactions of the design when manufactured with sundry dynamic factors in the world.

 Standing outside the program of design activity there is a discontinuity between the fixedness and time-independency of the output (design) (it exists) and the dynamic outcomes consequent to it in the world as a result of its behaviours and the changes in behaviours of the contexts in which it occurs.

  • Outputs are the designs, created within the program of design. Typically each design is fixed and independent of time
  • Outcomes are the consequences in the world outside the program of design of the outputs (designs). Typically the outcomes are characterised by being dynamically changing over time that is they are time dependent and also dependent on interaction with dynamically changing factors in the world

 In reality there are multiple discontinuities. Firstly, there is the discontinuity due to the difference in nature between outcomes and outputs. Secondly, this discontinuity reveals another discontinuity within the commissioning, design and evaluation process. The outcomes are the focus and purpose of those commissioning a design. Yet the primary focus of designers is to produce the outputs. To date, the evidence of problems due this discontinuity between outcomes and outputs is found in the lack of design practices, methods, theories, education and philosophical analysis for ways to accurately predict the dynamic behaviour of the outcomes resulting from any specific design output. It points to a gap in the methods, theory and philosophy of design literatures relating to this issue.

Design complexity

Conventionally, it is assumed in many areas of design that all design is complex and all designs are located on a continuum of complexity that is similar in nature if not degree. This is contradicted by mapping design situations against four categories used in systems science:

1.       Simple systems: These have a small number of elements, a small number of interrelationships between elements and no feedback loops. Their outcomes are fixed in regard to time and can be identified by observation and ‘in mind’.

2.       Complicated systems: These have a larger number of elements, a larger number of interrelationships between elements. Their outcome behaviour is also fixed in time and may be understood by observation and ‘in mind’, subject to limitations of scale.

3.       Complex systems: These have any number of elements, any number of interrelationships between elements and feedback loops. Their outcome behaviour is dynamic and by observation cannot be predicted ‘in mind’ by an individual or group unaided for systems with two or more feedback loops. The dynamics of the outcome behaviours are intrinsically predictable, however, using dynamic modelling, which offers designers the ability to see how the outcome behaviours play out over time.

4.       Chaotic systems: These have any number of elements, any number of interrelationships between elements and feedback loops. The relationships between elements result in the dynamics of the outcome behaviours being intrinsically unpredictable, including in mind.

Simple and complicated systems form a continuum. For most designers in the Art and Design fields, design education and the reasoning to identify design outputs from briefs is for designs characterised as being simple or complicated systems.

There is a discontinuity, however, between the first two classes of systems (simple and complicated) and the second two classes of systems (complex and chaotic systems). The first two classes of systems are linear and hence mentally their behaviour is easy to predict and the outcome is fixed. The second two classes of system are non-linear and prediction of their outcomes typically requires dynamic modelling of some sort.

The implication for design practices, methods, theories and philosophy of design is the existence of two separate bodies of theory and analysis: one for Conventional design (involving only simple and complicated situations), and one for r Complex design whose behaviour is complex or chaotic.

Visual representation of design situations

Conventionally, it is often explicitly or implicitly claimed that all design situations, regardless of how complex, can be represented in by a fixed 2D visual diagram such as those created by Tufte (e.g. Tufte, 2001) and Horn (see, e.g. Horn, 2001; Horn, 2007).

Tufte and Horn use their visual information mapping and visual analytics diagramming tools to describe relationships between data that may be complicated but it is time-independent in the sense that the data does not dynamically change during its presentation. For time independent data, i.e. data fixed in time, fixed 2D representation of information is sufficient. This is true regardless of how complicated it is.

In contrast, the data representing complex situations is dynamic and time-dependent. This results in a discontinuity between representing complicated data that is fixed and representing complex situations in which the behaviour to be represented changes over time and is dependent on interrelationships with the behaviour of other factors in the present and past (Rickles, Hawe, & Shiell, 2007). Whereas it is possible to fully and accurately represent time-independent information in diagrams and this may help individuals to think bigger thoughts, representing dynamic time-dependent situations requires that the diagram also changes in time, i.e. is dynamic in the sense that a video is dynamic and changes over time compared to a photograph. This is particularly an issue for prediction of the future behaviour of outcomes of a dynamic time-dependent situation that depends on multiple dynamically varying factors.

The above reveals a discontinuity between:

1.       Visual representation of time independent information typical of the design of simple and complicated situations, which can be achieved by fixed 2D visual diagramming

2.       Visual representation of time dependent predictions of dynamic behaviours typical of the design of complex and chaotic situations, which require dynamic representation of behaviours and the behaviours of the multiple dynamically varying factors on which the primary behaviour depends.

This discontinuity in the design realm is closely connected to the other discontinuities in this section. For example, the elements of this discontinuity map tightly with the discontinuity between outputs (time independent and commonly involving simple and complicated design) and well suited to 2D fixed diagrams, and outcomes (typically time independent complex design situations) that require modelling to predict their dynamic behaviours over time as shaped by other multiple dynamically varying factors.

The implication for design practices, methods, theories and philosophy of design is again the establishment of two separate bodies of theory and analysis relating to representation of design-related information: one for Conventional design (involving only simple and complicated situations), and one for Complex Design.

Predicting the behaviours of outcomes

Conventionally, it is explicitly or implicitly assumed in many areas of design that the quality designs can be evaluated by testing the design itself by judgement of peers and experts. Questions that illustrate this approach include; ‘Is it a good/bad/cool design?’, ‘Does it satisfy the required loads?’, ‘Does it fulfil the safety requirements?’ and ‘Does it satisfy the required usability standards?’ These are evaluations of designs as outputs

Some designs are also evaluated by investigating outcomes in the public arena. Evaluations of outcomes typically include, for example, the levels of revenue and profitability, changes in market share, and measures of effectiveness such as changes in health statistics for health promotion posters.

Both of the above forms of evaluation assume outcomes consequent on a design output are fixed in nature. That is, they can be found by simple measurement or judgement and are constant. This latter assumption is evidenced in any question about the quality of a design that does not ask how the outcomes of a design will change over time.

In contrast, the evaluation of outcomes of a complex design will require addressing the reality that the behaviours of the outcomes will be dynamic, changing over time. The outcomes will be shaped by, and will in turn reshape, and be shaped again by, the behaviours of other factors in the world in a dynamic dance that typically requires dynamic modelling to predict.

The above reveals a discontinuity with regard to evaluation of designs in relation to:

  • Evaluations of designs as outputs, or by evaluating the behaviour of outcomes in terms of fixed time independent values. This kind of evaluation of the behaviour of outcomes may be seen as either appropriate in validity only to simple designs that have outcomes with non-complex behaviours (unlikely), or as being insufficient or invalid.
  • Evaluations of the behaviours of outcomes of a design by predicting the dynamics of the behaviour of outcomes resulting from the interactions of the design in the public realm with other dynamic factors in ways that involve feedback loops assuming the behaviours will be complex.

Again this discontinuity is closely connected to the other discontinuities and the implication for design practices, methods, theories and philosophy of design is the establishment of two separate bodies of theory and analysis: one for Conventional design (involving only simple and complicated situations), and one for Complex Design whose behaviour is complex or chaotic.

This issue of predicting the dynamic behaviour of outcomes is also significant for other reasons that will be discussed later in the paper.

Human design abilities and limits

 Conventionally, it is explicitly or implicitly assumed in many areas of design by designers, researchers and design theorists that humans are not limited in their ability to design: that creativity is infinite; that intuition and emotion identify the correct solutions to problems that designers find hard to identify solutions analytically; and that understanding and knowledge is additive to the extent that a discussion group can always address problems that cannot be understood and resolved by a single person.

 In all other areas of human endeavour it is clear human physiological and biological limits exist that shape and put boundaries on what we can do. For example, our range of possible body temperature is small and exceeding it results in death. Physiological limits apply to our use of thinking, emotions, feeling, memory and intuition in other contexts. For example, we cannot easily take into consideration more than about 7 items (Miller 1956). We invent false memories and convince ourselves they are true as shown for example in Fisher and Tversky’s work on eyewitness testimony (Engelhardt 1999; Marsh, Tversky, & Hutson, 2005). Our understanding is limited by all of us having the inbuilt mechanisms to support perceptual illusions []. We are capable of justifying false beliefs: regardless of justification, they are false. We have widespread problems with reasoning as identified by fallacies or errors of reasoning (see, e.g., Good, 1962). One the emotional side, errors of emotionally-based thinking are widespread and the subject of whole fields of practice and enquiry such as advertising (Heath, 2012) of which neurologically-based subconscious marketing that takes advantage of our limited ability to be aware of it is available by organisations such as Buyology ( Errors of intuition are closely linked to errors of emotion (Baron, 1998). A particular intuitive error is assuming that intuition is a replacement for analysis (as proposed by Gladwell (2005) in Blink). Apparently, Lehmann of Lehman’s bank that failed in the global financial crisis hired Gladwell to encourage their employees to use intuition when addressing difficult issues [ . In the limit, we can be manipulated to change our understanding by rhetoric (VanDijk, 2006). All of these indicate our processes of judgement and conceptualisation are limited physiologically.

Conventionally, it is also explicitly or implicitly assumed in many areas of design that designers have the ability to successfully address any design problem subjectively in-mind (i.e. think of the correct creative idea) provided sufficient design talent, creativity, feeling, intuition, emotion and communication with stakeholders is available. Research by the author has focused on the biological limits of human design ability and the complexity of design problems that can be addressed (e.g., Love, 2009; T Love, 2010; T. Love, 2010). One aspect that emerged was an illusion in which individuals who were unable to fully conceive a complex situation and predict dynamic behaviour of design outcomes, nevertheless were convinced that they had correctly done so.

 The above points to a discontinuity between two types of design activity:

 1.       Designs that can be undertaken by humans ‘in mind’ within their physiological limits and in which human internal subjective, emotional, intuitive and creative expertise, perhaps in collaboration with others, is sufficient to predict the behaviour of designs’ outcomes.

2.       Designs that are beyond human physiological limits internal abilities of thinking, feeling, intuition, creativity or emotions to conceive and predict the dynamic behaviour of the design-related outcomes

This discontinuity aligns with the other discontinuities above and defines two completely distinct types of valid design process. The second of which depends on dynamic modelling or similar external processes to replace human abilities to fully understand the design situation and predict the behaviour of outcomes.

Again, the implication for design practices, methods, theories and philosophy of design is the need for two separate bodies of theory and analysis: one for Conventional design (involving only simple and complicated situations), and one for Complex design whose behaviour is complex or chaotic and which avoids the assumptions implicit in the first body of literature addressing time independent design situations.

Implications for Design Practices, Theory and Philosophy of Design

The focus of this paper has been to draw attention to epistemological, ontological and methodological discontinuities in relation to design theory and the philosophy of design that to date appears to have been overlooked. In particular it has focused on the commonly held assumption that human abilities to address design problems is infinite because there is significant evidence this is not so. It reveals a discontinuity in relation to design activities and problems undertaken by designers within humans’ physiologically defined limitations, and those design activities and problems whose complexity exceeds what humans have physiological ability to undertake subjectively.

All the discontinuities identified in the paper to a large extent appear to coincide to a single boundary. This boundary defines two distinctly separate sets or regions of design activity, design theory and philosophy of design. The analyses suggest conventional approaches to design, and related theorising and philosophising about design apply only to one side of this boundary. The fact that the boundary is one of discontinuity means the design practices, methods, theory and philosophy of design on the other side of the boundary, those relating to Complex Design are by implication epistemologically and ontologically different.

Implications for participative and collaborative design

One implication from the above analysis is that participatory or collaborative in their conventional forms are unsuited to complex design problems. If a non-decomposable complex situation is too complex for one person to hold in mind, then having a group address the same complex design issue does not offer any advantage. It results in multiple individuals of whom none are capable of predicting outcomes together with no means of recomposing or combing their abilities. The analysis is straight forward. Assume the design problem has been decomposed and remains complex. For complex design involving feedback loop relationships between factors, where individuals undertake their design ‘in mind’ or in terms of fixed diagrams, they will be unable to capture and process all the behaviours and relationships between elements that enable any individual to be able to predict the behaviour of the design outcomes. In other words, they are unable to predict the behaviours of the design outcomes. To understand and predict the behaviour of a design, it is necessary to be able to hold and process it and all the relevant factors wholly in mind. If one individual cannot achieve this, there is no benefit in having multiple participants because such a design is not decomposable, i.e. it cannot be recomposed by combining partial aspects of the design by different participants or stakeholders. This implication is significant because it contradicts the underlying reasoning justifying participative and collaborative design. It suggests the benefits of participative or collaborative design are restricted to simple and complicated design contexts and not valid for complex design situations

Implications for ‘wicked problems’

Interestingly, ‘wicked problems’ by Rittel’s definition fall on the Complex Design side of the discontinuity boundary. This side of the boundary contains design problems exceeding the physiological limitations of subjective abilities of humans as individuals, i.e. cannot be done by conventional design. It may explain why designers using conventional design are ineffective at addressing ‘wicked problems’. In the experience of the author and systems dynamics practitioners, this makes sense, many, perhaps all, wicked problems appear to be addressable using dynamic modelling approaches for complex design: provided human subjective approaches are avoided in making design decisions.

A need for new design processes, theories and philosophy of design

The above analyses point to the need for a new body of design theory and philosophy of design that addresses issues on the complex design side of the discontinuity boundary. They surface a raft of philosophical issues relating to practical methods and professional issues in complex design situations. They also point to practical solutions and methods for addressing the issues. For example, they suggest an easy-to-use practical tool to identify which side of the boundary a problem is located (see next) and defining characteristics of design processes (see following) that require external modelling to address complex design beyond human biological limitations for using human subjective faculties for predicting the dynamic behaviours of design outcomes.

Practical tool for identifying the type of design problem

As reported by the author elsewhere, the boundary discontinuity between Conventional Design (simple and complicated situations) and Complex Design (complex and chaotic situations) appears to be defined by the design situation containing two or more feedback loops (Love, 2009; T Love, 2010; T. Love, 2010). Causal Loop Diagramming offers an easy to use manual tool for this purpose.

Characteristics of a design process for complex design

A crucial issue that marks the discontinuity boundary between Conventional Design (simple and complicated situations) and Complex Design (complex and chaotic situations) is the need for modelling of the dynamic behaviour of the design in its interaction with the environment to predict the dynamic behaviour of outcomes. This clearly changes the role of the designer, who for simpler design situations undertook this task of envisaging outcomes ‘in-mind’ using thinking, feelings, intuition, emotions and creativity.

For complex design, where the modelling of the behaviour of a design and its outcomes must be externalised this suggests the characteristics of a design process as follows:

1.       Receive brief including expectation of outcomes

2.       Gather information from stakeholders

3.       Undertake decomposition where possible

4.       Use the above information to develop dynamic model to predict the dynamic behaviour of outcomes

5.       Test and evaluate the dynamic model against real world data and expectations

6.       Speculate on a design and include it in the dynamic model

7.       With stakeholders speculate on changes to the design and rerun the dynamic model to observe the consequences form the changes.

8.       In consultation, identify which dynamic trajectories of outcomes are preferred by stakeholders

9.       Decision making for preferred design output

10.   Evaluation of designs and modelling in terms of the quality of knowledge, process, modelling, decision making and the behaviour of outcomes

The above processes result in transition of designers into new roles. Designers move towards becoming facilitators and researchers, and away from using emotions and intuition to subjectively envisage outcomes resulting from potential design outputs.

Philosophy of design issues

In the realm of Philosophy of Design, the above analyses and the separation of Conventional Design and Complex Design as described above raises several areas to be reconsidered and several questions:

  • ·         Competence of design implies designers create designs that achieve the outcomes intended. This presumes for competence, designers are able to predict outcomes resulting from their design output. This prediction is a fundamental aspect of any form of professional competence. It is not currently undertaken by many designers. Should it be?
  • ·         Professional ethics. How does the above competence issue relating to predicting outcomes resulting from a design factor into professional ethics?
  • ·         How do these issues factor into designers’ liabilities and responsibilities to clients, stakeholders and others?
  • ·         What changes in roles are implied for all parties involved in Complex Design?
  • ·         How will evaluation be undertaken of design theories and methods for Complex Design in terms of quality of knowledge, process, modelling, decision making and prediction of the behaviour of outcomes?
  • ·         What kinds of different meta-understanding of design theory will be needed that change the focus from designers and conventional designer activity to the human interactions of stakeholders, knowledge elicitation, modelling, decision making and evaluation of predictiveness?

Implications for design education

The discontinuity boundary in design activities identified above has implications for design activity and hence for design education. The boundary involves multiple discontinuities each with implications for how design is theorised about, and hence how designers are taught.

Implications for the design thinking movement

The assumptions underpinning the recent movement to implement a process of Design Thinking across all disciplines and problem types depends on is contradicted by the discontinuities identified above, particularly the combination of physiological subjective limitations and problems of addressing complex design situations. These would appear to contradict the assumptions of continuity on which depend the proposal Design Thinking is universally applicable.

Conclusions and Summary

 The paper has drawn attention to the significance of discontinuities in factors relating to design practices, methods and theories that were otherwise presumed to be continuums.

This has multiple implications for design practices and theories. The first is it challenges the validity of theories and practices that were based on the assumptions of continuity and continuums of function. The details of how it does so are described in earlier sections.

Secondly, the paper has drawn attention to the significance of one particular discontinuity; that of physiological limitations of the subjective faculties humans use in creating designs: thinking, feeling, intuition, emotions and creativity. It draws attention to the fact that these faculties are bounded and limited like any biological ability, whereas in design theory and practices they are typically assumed to be unbounded and unlimited. The fact they are bounded results in a discontinuity between design issues addressed in ways in which the human subjective faculties exceed what is necessary to address the design issues, and those in which the human subjective faculties are insufficient. It corresponds to a discontinuity in the relative complexity of design situations; identified as complex design situations involving two or more feedback loops. This latter discontinuity marks the point at which their complexity of design situations exceeds the ability of humans to conceive their causal relations ‘in-mind’ and accurately predict their outcomes using subjective facilities. The discontinuity of physiologically-based limitation of humans’ subjective faculties presents a challenge on multiple fronts to assumptions underpinning conventional design practices and theories, as well as the practices and theories themselves

Third, the paper has drawn attention to the co-incidence of the above multiple discontinuities in a way that creates a boundary in design activities. Conventional Design is located on one side of the boundary, and design activity operating on a different basis, Complex Design, lies on the other. This region of Complex design, also includes what has previously been known as ‘wicked design problems’.

Following on from the above, the paper has also identified:

  • Implications for theories and practices of participative and collaborative design
  • Implications for addressing ‘wicked problems’
  • A need for new design theories, practices and philosophy of design perspectives that include discontinuities
  • A practical tool for identifying design types, in line with the above discontinuity boundary
  • Characteristics of a design process for complex design
  • Issues for Philosophy of Design
  • The need to address the implications for design education
  • Implications for the design thinking movement

In conclusion, the paper has brought together multiple analyses relating to discontinuities. These discontinuities, singly and in combination, have deep implications for change for many core areas of design practice and theory that have assumed the same factors to be continuous. There are obviously more areas and dimensions of design that exhibit discontinuities than have been addressed here. The fact that design theories and practices have traditionally and consistently developed around assumptions of continuums and smooth continuity of functions and relationships suggests the study of discontinuities in design is an arena of promise for further research.


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