Dual-process and dual-system theories in both cognitive and social psychology have been subjected to a number of recently published criticisms. However, they have been attacked as a category, incorrectly assuming there is a generic version that applies to all. We identify and respond to 5 main lines of argument made by such critics. We agree that some of these arguments have force against some of the theories in the literature but believe them to be overstated. We argue that the (...) dual-processing distinction is supported by much recent evidence in cognitive science. Our preferred theoretical approach is one in which rapid autonomous processes are assumed to yield default responses unless intervened on by distinctive higher order reasoning processes. What defines the difference is that Type 2 processing supports hypothetical thinking and load heavily on working memory. (shrink)

A step towards a theory of consciousness would be to characterise the effect of consciousness on information processing. One set of results suggests that the effect of consciousness is to interfere with computations that are optimally performed non-consciously. Another set of results suggests that conscious, system 2 processing is the home of norm-compliant computation. This is contrasted with system 1 processing, thought to be typically unconscious, which operates with useful but error-prone heuristics. -/- These results can be reconciled by (...) separating out two different distinctions: between conscious and non-conscious representations, on the one hand, and between automatic and deliberate processes, on the other. This pair of distinctions is used to illuminate some existing experimental results and to resolve the puzzle about whether consciousness helps or hinders accurate information processing. This way of resolving the puzzle shows the importance of another category, which we label ‘type 0 cognition’, characterised by automatic computational processes operating on non-conscious representations. (shrink)

Despite their popularity, dual process accounts of human reasoning and decision-making have come under intense scrutiny in recent years. Cognitive scientists and philosophers alike have come to question the theoretical foundations of the ‘standard view’ of dual process theory and have challenged the validity and relevance of evidence in support of it. Moreover, attempts to modify and refine dual process theory in light of these challenges have generated additional concerns about its applicability and refutability as (...) a scientific theory. With these concerns in mind, this paper provides a critical review of dual process theory in economics, focusing on its role as a psychological framework for decision modeling in behavioral economics and neuroeconomics. I argue that the influx of criticisms against dual process theory challenge the descriptive accuracy of dualistic decision models in economics. In fact, the case can be made that the popularity of dual process theory in economics has less to do with the empirical success of dualistic decision models, and more to do with the convenience that the dual process narrative provides economists looking to explain-away decision anomalies. This leaves behavioral economists and neuroeconomists with something of a dilemma: either they stick to their purported ambitions to give a realistic description of human decision-making and give up the narrative, or they revise and restate their scientific ambitions. (shrink)

The paper presents some essential heuristic and constructional elements of Free Process Theory (FPT), a non-Whiteheadian, monocategoreal framework. I begin with an analysis of our common sense concept of activities, which plays a crucial heuristic role in the development of the notion of a free process. I argue that an activity is not a type but a mode of occurrence, defined in terms of a network of inferences. The inferential space characterizing our concept of an activity entails (...) that anything which is conceived of as occurring in the activity mode is a concrete,dynamic, non-particular individual. Such individuals, which I call free processes, may be used for the interpretation of much more than just common sense activities. I introduce the formal theory FPT, a mereology with anon-transitive part-relation, which contains a typology of processes based on the following five parameters relating to: (a) patterns of possible spatial and temporal recurrence (automerity); (b) kinds of components (participant structure); (c) kinds of dynamic composition; (d) kinds of dynamic flow (dynamic shape); and (e) dynamic context. I show how these five evaluative dimensions for free processes can be used to define ontological correlates for various common sense categories,and to draw distinctions between various forms of agency(distributed, collective, reciprocal, entangled) and emergence (weak, strong,as autonomous system (Bickhard/Christensen)). (shrink)

The biggest benefit of dual-process theory lies in its role as a benchmark theory that, regardless of its empirical plausibility, serves as a starting point for better and more domain-specific models. In this sense, dual-process theory is the Barbapapa of psychological theory – a blob-shaped creature that can be reshaped and adapted to fit in the context of any human behavior.

Processes constitute the world of human experience - from nature to cognition to social reality. Yet our philosophical and scientific theories of nature and experience have traditionally prioritized concepts for static objects and structures. The essays collected here call for a review of the role of dynamic categories in the language of theories. They present old and new descriptive tools for the modelling of dynamic domains, and argue for the merits of process-based explanations in ontology, cognitive science, semiotics, linguistics, (...) philosophy of mind, robotics, theoretical biology, music theory, and philosophy of chemistry and physics. The collection is of interest to professional researchers in any of these fields; it establishes - for the very first time - crossdisciplinary contact among recent process-based research movements and might witness a conceptual paradigm shift in the making. (shrink)

The relationship between attention and consciousness is one that is crucial for understanding perception and different types of conscious experience, and we commend this analysis of the topic by Pitts, Lutsyshyna, and Hillyard (2018). We have also examined this relationship closely (e.g., Montemayor & Haladjian, 2015) and would like to point out a few potential contradictions in the Pitts et al. paper that require clarification, particularly in the attempt to reconcile aspects of recurrent processing theory (RPT) with global neuronal (...) workspace theory (GNWT). This commentary addresses these points and introduces other considerations important for this topic. (shrink)

Part 1. Some problems of organization theory and the potential of process organization theory -- Why assumptions in organization theory do not work for explaining organizing in a world on the move -- Assumptions for organizing in a world on the move -- Part 2. Toward a process theory of organization -- Temporality and process -- Organization, meaning structures, and time -- Articulatory models and agency -- Part 3. Process theory and (...) selected aspects of organization management -- Process theory, organizational continuity, and change -- Managing and leading in time -- Organizational culture, identity, and institutions -- Some thoughts on studying process -- A plea for mystery. (shrink)

This anthology offers a unique collection of contributions focusing on the discussion about the so-called dual-process theories within the field of moral psychology. In general, dual-process theories state that in cognitive systems, two sorts of processes can be differentiated: an affective, associative process and an analytical, rule-based process. This distinction recently entered the debate on the relationship between intuitive and rational approaches to explaining the phenomenon of moral judgment. The increasing interest in these theories raises questions (...) concerning their general impact on social contexts. The anthology aims at presenting stepping-stones of an analysis of the merits and drawbacks of this development. For that purpose, the authors discuss general questions concerning the relationship between ethics and empirical sciences, methodological questions, reassessments of established terminology and societal implications of dual-process theories in moral psychology. (shrink)

Dual process theory proposes clusters of features that form two dichotomous groups in cognition. One standing internal issue is defining what the reference of these two dichotomous groups could be in the mind or brain. Does dual process theory speak of two systems, types, minds, modes, kinds or just metaphors? A particular common answer is that differences in clusters of features are evidence of different underlying systems, often called system 1 and system 2. However, the suggestion (...) to abandon the ‘system’ terminology is now common in the literature, but the consequences of doing so need to be addressed. This work reviews and critically discusses previous suggestions. (shrink)

Dual Process Theory is currently a popular theory for explaining why we show bounded rationality in reasoning and decision-making tasks. This theory proposes there must be a sharp distinction in thinking to explain two clusters of correlational features. One cluster describes a fast and intuitive process, while the other describes a slow and reflective one. A problem for this theory is identifying a common principle that binds these features together, explaining why they form a (...) unity, the unity problem. To solve it, a hypothesis is developed combining embodied predictive processing with symbolic classical approaches. The hypothesis, simplified, states that Type 1 processes are bound together because they rely on embodied predictive processing whereas Type 2 processes form a unity because they are accomplished by symbolic classical cognition. To show that this is likely the case, the features of Dual Process Theory are discussed in relation to these frameworks. (shrink)

Despite on-going debates in philosophy and cognitive science, dual process theory (DPT) remains a popular framework for theorizing about human cognition. Its central hypothesis is that cognitive processing can be subsumed under two generic types. In this paper, we argue that the putative success and popularity of this framework remains overstated and gives rise to certain misunderstandings. If DPT has predictive and/or explanatory power, it is through offering descriptions of cognitive phenomena via functional analysis. But functional descriptions require (...) an individuation strategy. To date, there has been no systematic exploration of how Type 1 and Type 2 are functionally individuated. Following recent debates in philosophy of cognitive science, we consider three individuation strategies (i.e., abstraction, reification, fictionalization) and assess the legitimacy of each in relation to DPT. This leads us to the verdict that the most viable route for justifying DPT is to construe Type 1 and Type 2 processes as reifications. We conclude that, construed as reifications, the common rationales offered by proponents of DPT for demarcating Type 1 and Type 2 processes do not escape criticism and require further theoretical justification. (shrink)

In this paper, it is argued that single function dual process theory is a more credible psychological account of non-monotonicity in human conditional reasoning than recent attempts to apply logic programming (LP) approaches in artificial intelligence to these data. LP is introduced and among other critiques, it is argued that it is psychologically unrealistic in a similar way to hash coding in the classicism vs. connectionism debate. Second, it is argued that causal Bayes nets provide a framework for (...) modelling probabilistic conditional inference in System 2 that can deal with patterns of inference LP cannot. Third, we offer some speculations on how the cognitive system may avoid problems for System 1 identified by Fodor in 1983. We conclude that while many problems remain, the probabilistic single function dual processing theory is to be preferred over LP as an account of the non-monotonicity of human reasoning. (shrink)

This book presents a philosophical interpretation to numerical cognition based on dual process theories and heuristics. It shows how investigations in cognitive science can shed light on issues traditionally raised by philosophers of mathematics. The analysis will also help readers to better understand the relationship between current neuroscientific research and the philosophical reflection on mathematics. The author seeks to explain the acquisition of mathematical concepts. To accomplish this, he needs to answer two questions. How can the concepts of approximate (...) numerosity become an object of thought that is so accessible to our consciousness? How are these concepts refined and specified in such a way as to become numbers? Unfortunately, there is currently no model that can truly demonstrate the role of language in the development of numerical skills starting from approximate pre-verbal skills. However, the author details a solution to this problem: dual process theories. It is an approach widely used by theorists focusing on reasoning, decision making, social cognition, and consciousness. Here, he applies this approach to the studies on mathematical knowledge. He details the results brought about by psychological and neuroscientific studies conducted on numerical cognition by key neuroscientists. In the process, he develops the foundations of a new, potential philosophical explanation on mathematical knowledge. (shrink)

In this paper, I seek an account of the nature of epistemic intuition. Given the resources of Dual-Process Theory in Psychology, I argue that the intuitions of elite epistemologists, such as Fred Dretske, are not a priori, pre-theoretic, insights. Instead, they are a posteriori insights into the phenomena of knowledge, not the concept of knowledge. Dretske intuitions are technical, modal intuitions about hypothetical counterfactual cases using System II reflections. Such intuitions depended on thinking about the implications of laws (...) of nature in particular circumstances and were used to defend Dretske’s reliable indicator account of knowledge. That account suggested that one must have conclusive reasons when one has empirical knowledge that P. (shrink)

The distinction between such differing approaches to cognition as connectionism and rule-based models is paralleled by a distinction between two basic modes of cognition postulated in the so-called dual-process theories. Integrating these theories with insights from hybrid systems might help solve the dilemma of combining the demands of evolutionary plausibility and computational universality. No single approach alone can achieve this.

Critics of the organization of industrial work under capitalism have ranged from the “human relations” school to socio‐technical systems theorists and, most vociferously, to advocates of labor process theory (LPT). Their practical influence on management was small as long as production was rolling on and profits rolling in. When competition intensified, however, employers started to question old ideas and, abetted by the needs of new computerized technology, began to broaden jobs, allow workers greater discretion in their performance and (...) involve them in shop floor decision making. LPT, however, has not contributed to this evolution toward more satisfying work. This paper explains why this is so by exploring two major shortcomings of LPT. First and foremost is that LPT has ignored the efficiency of the work process, refusing to acknowledge the legitimacy of a tradeoff between work “goodness” and productivity.As a result, LPT has been unable to propose economically viable alternatives to existing job design and work organization. Second, LPT has identified management's goal in organizing work as gaining control of the process, when, in fact, it has been to make the process as economically efficient as possible. Thus, LPT could not see that, under changed circumstances, management might decentralize control toward the shop floor, if that might promote efficiency. LPT's founder, Harry Braverman, and his disciples believed that it was impossible to reform work under capitalism, but experience shows otherwise. (shrink)

This paper examines Wesley Salmon's "process" theory of causality, arguing in particular that there are four areas of inadequacy. These are that the theory is circular, that it is too vague at a crucial point, that statistical forks do not serve their intended purpose, and that Salmon has not adequately demonstrated that the theory avoids Hume's strictures about "hidden powers". A new theory is suggested, based on "conserved quantities", which fulfills Salmon's broad objectives, and which (...) avoids the problems discussed. (shrink)

Since the failure of both pure corpuscular and pure wave philosophies of nature, process theories assume that only events need to exist in order to have a physics. Starting from an ontology of actual events, a dispositional analysis is shown here to lead to a new idea of substance, that of a `distribution of potentiality or propensity'. This begins to provide a useful foundation for quantum physics. A model is presented to show how the existence of physical substances could (...) be a reasonable consequence of a theory of processes. (shrink)

Enzymes are protein catalysts of extraordinary efficiency, capable of bringing about rate enhancements of their biochemical reactions that can approach factors of 1020. Theories of enzyme catalysis, which seek to explain the means by which enzymes effect catalytic transformation of the substrate molecules on which they work, have evolved over the past century from the “lock-and-key” model proposed by Emil Fischer in 1894 to models that explicitly rely on transition state theory to the most recent theories that strive to (...) provide accounts that stress the essential role of protein dynamics. In this paper, I attempt to construct a metaphysical framework within which these new models of enzyme catalysis can be developed. This framework is constructed from key doctrines of process thought, which gives ontologic priority to becoming over being, as well as tenets of a process philosophy of chemistry, which stresses environmentally responsive molecular transformation. Enzyme catalysis can now be seen not as enzyme acting on its substrate, but rather as enzyme and substrate entering into a relation which allows them to traverse the reaction coordinate as an ontologic unity. (shrink)

Two prevailing accounts of the structure of the mind have been provided, respectively, by the Dual System Theory and by the Massive Modularity Hypothesis. It has been claimed, however, that they cannot both be true at the same time, i.e., that they are incompatible and, thus, that one of them must be abandoned. I will offer some arguments to challenge this claim. I will show that a plausible understanding of each theory makes it possible for them both to (...) be true at the same time. Moreover, I will argue that by appealing to each other they can offer a more complete and detailed account of the architecture of the mind. (shrink)

De Neys (2021) argues that the debate between single- and dual-process theorists of thought has become both empirically intractable and scientifically inconsequential. I argue that this is true only under the traditional framing of the debate—when single- and dual-process theories are understood as claims about whether thought processes share the same defining properties (e.g., making mathematical judgments) or have two different defining properties (e.g., making mathematical judgments autonomously versus via access to a central working memory capacity), respectively. But (...) if single- and dual-process theories are understood in cognitive modeling terms as claims about whether thought processes function to implement one or two broad types of algorithms, respectively, then the debate becomes scientifically consequential and, presumably, empirically tractable. So, I argue, the correct response to the current state of the debate is not to abandon it, as De Neys suggests, but to reframe it as a debate about cognitive models. (shrink)

Given certain well-known observations by Mach and Russell, the question arises what place there is for causation in the physical world. My aim in this chapter is to understand under what conditions we can use causal terminology and how it fi ts in with what physics has to say. I will argue for a disposition-based process-theory of causation. After addressing Mach’s and Russell’s concerns I will start by outlining the kind of problem the disposition based process-theory (...) of causation is meant to solve. In a second step I will discuss the nature of those dispositions that will be relevant for our question. In section 3 I will discuss existing dispositional accounts of causation before I proceed to present my own account (sections 4 to 6) and contrast it with traditional process-theories (section 7). (shrink)

In this commentary on Stanovich & West (S&W) we call attention to two points: (1) Freud's original dual process theory, which antedates others by some seventy-five years, deserves inclusion in any consideration of dual process theories. His concepts of primary and secondary processes (Systems 1 and 2, respectively) anticipate significant aspects of current dual process theories and provide an explanation for many of their characteristics. (2) System 1 is neither rational nor irrational, but instead a-rational. Nevertheless, (...) both the a-rational System 1 and the rational System 2 can each have different roles in enhancing evolutionary fitness. Lastly, System 1 operations are incorrectly deemed “rational” whenever they increase evolutionary fitness. (shrink)

Recent work in cognitive modelling has found that most of the data that has been cited as evidence for the dual-process theory (DPT) of reasoning is best explained by non-linear, “monotonic” one-process models (Stephens et al., 2018, 2019). In this paper, I consider an important caveat of this research: it uses models that are committed to unrealistic assumptions about how effectively task conditions can isolate Type-1 and Type-2 reasoning. To avoid this caveat, I develop a coordinated theoretical, (...) experimental, and modelling strategy to better test DPT. First, I propose that Type-1 and Type-2 reasoning are defined as reasoning that precedes and follows metacognitive control, respectively. Second, I argue that reasoning that precedes and follows metacognitive control can be effectively isolated using debiasing paradigms that manipulate metacognitive heuristics (e.g., processing fluency) to prevent or trigger metacognitive control, respectively. Third, I argue that monotonic modelling can allow us to decisively test DPT only when we use them to analyse data from this particular kind of debiasing paradigm. (shrink)

In response to the claim that the properties typically used to distinguish System 1 from System 2 crosscut one another, Carruthers, Evans, and Stanovich have abandoned the System 1/System 2 distinction. Evans and Stanovich both opt for a dual-process theory, according to which Type-1 processes are autonomous and Type-2 processes use working memory and involve cognitive decoupling. Carruthers maintains a two-system account, according to which there is an intuitive system and a reflective system. I argue that these defenses (...) of dual-process theory face two problems. First, as pointed out by Sloman, these new dual-process theories cast the net of “reasoning” too wide. Second, and more importantly, this singular distinction cannot accomplish the explanatory work needed to support dual-process theory. These theorists must fall back on using various properties from the Standard Menu in explanations, thereby committing these accounts to a “Standard View” that they had hoped to avoid. Thus, these theorists face a.. (shrink)

There is a widespread belief that the so-called process theories of causation developed by Wesley Salmon and Phil Dowe have given us an original account of what causation really is. In this paper, I show that this is a misconception. The notion of “causal process” does not offer us a new ontological account of causation. I make this argument by explicating the implicit ontological commitments in Salmon and Dowe’s theories. From this, it is clear that Salmon’s Mark Transmission (...) Theory collapses to a counterfactual theory of causation, while the Conserved Quantity Theory collapses to David Fair’s phsyicalist reduction of causation. (shrink)

A combination of process and counterfactual theories of causation is proposed with the aim of preserving the strengths of each of the approaches while avoiding their shortcomings. The basis for the combination, or hybrid, view is the need, common to both accounts, of imposing a stability requirement on the causal relation.

Byrne & Hilbert (B&H) give some excellent replies to the objections to realism about color. However, the particular form of realism they propose, based on opponent processing, prompts several challenges. Why characterize a color by its tendency to produce an intermediate brain signal, rather than in terms of the final effect – either a perception or a neural substrate for it? At the level of the retina, and even of the cortex, there are processes that partly parallel the structure of (...) color experience; but the correspondence is not exact. Must we assume that there is any place in the brain where an exact structural correspondence is found? At the level of psychophysical functioning, there is indeed opponency; but it is not clear that this gives us the kind of type-reduction that B&H want. (shrink)

Information processing theories in psychology give rise to executive theories of consciousness. Roughly speaking, these theories maintain that consciousness is a centralized processor that we use when processing novel or complex stimuli. The computational assumptions driving the executive theories are closely tied to the computer metaphor. However, those who take the metaphor serious — as I believe psychologists who advocate the executive theories do — end up accepting too particular a notion of a computing device. In this essay, I examine (...) the arguments from theoretical computational considerations that cognitive psychologists use to support their general approach in order to show that they make unwarranted assumptions about the processing attributes of consciousness. I then go on to examine the assumptions behind executive theories which grow out of the computer metaphor of cognitive psychology and conclude that we may not be the sort of computational machine cognitive psychology assumes and that cognitive psychology''s approach in itself does not buy us anything in developing theories of consciousness. Hence, the state space in which we may locate consciousness is vast, even within an information processing framework. (shrink)

ABSTRACTIn order to explain the effects found in the heuristics and biases literature, dual-process theories of reasoning claim that human reasoning is of two kinds: Type-1 processing is fast, automatic, and associative, while Type-2 reasoning is slow, controlled, and rule based. If human reasoning is so divided, it would have important consequences for morality, epistemology, and philosophy of mind. Although dual-process theorists have typically argued for their position by way of an inference to the best explanation, they have (...) generally failed to consider alternative hypotheses. Worse still, it is unclear how we might test dual-process theories. In this article, I offer a one-system theory, which I call the Sound-Board Account of Reasoning, according to which there is one reasoning system which is flexible, allowing the properties used to distinguished Type-1 and Type-2 reasoning to cross-cut one another. I empirically distinguish my theory from the two dominant versions of dual-process theory (parallel... (shrink)

From experience, we know that some cognitive processes are effortless and automatic (or nearly automatic), while others are hard and deliberate. Dual process (DP) accounts of human cognition explain these differences by positing two qualitatively distinct types of cognitive processes within the human mind—types that cannot be reduced to each other. Because DP constructs are bound to show up in discourse on human cognition, decision-making, morality, and character formation, moral philosophers should take DP accounts seriously. Here, I provide an (...) overview of the current state of DP accounts—their basic tenets, major concepts, and the various models of the DP framework—and note some of its more salient criticisms from the psychological research community. Finally, I show that DP accounts’ commitment to a real qualitative distinction between rational and non-rational human behavior puts them at odds with a Thomistic/Aristotelian view of practical rationality. (shrink)

This paper aims to provide a theoretical framework for explaining the subjective character of pain experience in terms of what we will call ‘embodied predictive processing’. The predictive processing (PP) theory is a family of views that take perception, action, emotion and cognition to all work together in the service of prediction error minimisation. In this paper we propose an embodied perspective on the PP theory we call the ‘embodied predictive processing (EPP) theory. The EPP theory (...) proposes to explain pain in terms of processes distributed across the whole body. The prediction error minimising system that generates pain experience comprises the immune system, the endocrine system, and the autonomic system in continuous causal interaction with pathways spread across the whole neural axis. We will argue that these systems function in a coordinated and coherent manner as a single complex adaptive system to maintain homeostasis. This system, which we refer to as the neural-endocrine-immune (NEI) system, maintains homeostasis through the process of prediction error minimisation. We go on to propose a view of the NEI ensemble as a multiscale nesting of Markov blankets that integrates the smallest scale of the cell to the largest scale of the embodied person in pain. We set out to show how the EPP theory can make sense of how pain experience could be neurobiologically constituted. We take it to be a constraint on the adequacy of a scientific explanation of subjectivity of pain experience that it makes it intelligible how pain can simultaneously be a local sensing of the body, and, at the same time, a more global, all-encompassing attitude towards the environment. Our aim in what follows is to show how the EPP theory can meet this constraint. (shrink)

Joshua Greene and his colleagues have proposed a dual-process theory of moral decision-making to account for the effects of emotional responses on our judgments about moral dilemmas that ask us to contemplate causing direct personal harm. Early formulations of the theory contrast emotional and cognitive decision-making, saying that each is the product of a separable neural system. Later formulations emphasize that emotions are also involved in cognitive processing. I argue that, given the acknowledgement that emotions inform cognitive (...) decision-making, a single-process theory can explain all of the data that have been cited as evidence for Greene’s theory. The emotional response to the thought of causing harm may differ in degree, but not in kind, from other emotions influencing moral decision-making. (shrink)

This paper aims to provide a theoretical framework for explaining the subjective character of pain experience in terms of what we will call ‘embodied predictive processing’. The predictive processing (PP) theory is a family of views that take perception, action, emotion and cognition to all work together in the service of prediction error minimisation. In this paper we propose an embodied perspective on the PP theory we call the ‘embodied predictive processing (EPP) theory. The EPP theory (...) proposes to explain pain in terms of processes distributed across the whole body. The prediction error minimising system that generates pain experience comprises the immune system, the endocrine system, and the autonomic system in continuous causal interaction with pathways spread across the whole neural axis. We will argue that these systems function in a coordinated and coherent manner as a single complex adaptive system to maintain homeostasis. This system, which we refer to as the neural-endocrine-immune (NEI) system, maintains homeostasis through the process of prediction error minimisation. We go on to propose a view of the NEI ensemble as a multiscale nesting of Markov blankets that integrates the smallest scale of the cell to the largest scale of the embodied person in pain. We set out to show how the EPP theory can make sense of how pain experience could be neurobiologically constituted. We take it to be a constraint on the adequacy of a scientific explanation of subjectivity of pain experience that it makes it intelligible how pain can simultaneously be a local sensing of the body, and, at the same time, a more global, all-encompassing attitude towards the environment. Our aim in what follows is to show how the EPP theory can meet this constraint. (shrink)

Volume 26, Issue 2, May 2020, Page 151-158.