In this book, T. M. Scanlon offers new answers to these questions, as they apply to the central part of morality that concerns what we owe to each other.

Psychopathy is a developmental disorder associated with specific forms of emotional dysfunction and an increased risk for both frustration-based reactive aggression and goal-directed instrumental antisocial behavior. While the full behavioral manifestation of the disorder is under considerable social influence, the basis of this disorder appears to be genetic. At the neural level, individuals with psychopathy show atypical responding within the amygdala and ventromedial prefrontal cortex. Moreover, the roles of the amygdala in stimulus-reinforcement learning and responding to emotional expressions and vmPFC (...) in the representation of reinforcement expectancies are compromised. The implications of these functional impairments for responsibility are discussed. (shrink)

Various social animal species have been noted to inhibit aggressive attacks when a conspecific displays submission cues. Blair (1993) has suggested that humans possess a functionally similar mechanism which mediates the suppression of aggression in the context of distress cues. He has suggested that this mechanism is a prerequisite for the development of the moral/conventional distinction; the consistently observed distinction in subject's judgments between moral and conventional transgressions. Psychopaths may lack this violence inhibitor. A causal model is developed showing how (...) the lack of this mechanism would explain the core behavioural symptoms associated with the psychopathic disorder. A prediction of such a causal model would be that psychopaths should fail to make the moral/conventional distinction. This prediction was confirmed. The implication of this finding for other theories of morality is discussed. (shrink)

Sentimental Rules is an ambitious and highly interdisciplinary work, which proposes and defends a new theory about the nature and evolution of moral judgment. In it, philosopher Shaun Nichols develops the theory that emotions play a critical role in both the psychological and the cultural underpinnings of basic moral judgment. Nichols argues that our norms prohibiting the harming of others are fundamentally associated with our emotional responses to those harms, and that such 'sentimental rules' enjoy an advantage in cultural evolution, (...) which partly explains the success of certain moral norms. This has sweeping and exciting implications for philosophical ethics. Nichols builds on an explosion of recent intriguing experimental work in psychology on our capacity for moral judgment and shows how this empirical work has broad import for enduring philosophical problems. The result is an account that illuminates fundamental questions about the character of moral emotions and the role of sentiment and reason in how we make our moral judgments. This work should appeal widely across philosophy and the other disciplines that comprise cognitive science. (shrink)

The chapter focuses on the philosophical debate between moral motivational internalism and externalism. The author analyzes and thereby challenges the conceptual problems underlying this quarrel in relation to the apparent empirical findings on psychopathy. Major obstacles in making progress in this debate are conceptual and methodological problems. First, there is not a clear-cut and undisputed definition of moral internalism. Second, empirical results about a lack of moral judgment are not forthcoming, since it is not certain how to test such an (...) impairment, and also who is to count as psychopaths in the first place. In conclusion both externalists and internalists are wrong in some respect: internalists in that they see an internal connection between moral judgments and motivation, externalists in their rejection of internalism on grounds of findings about psychopathy. (shrink)

The illusory appeal of double effect -- The significance of intent -- Means and ends -- Blame.

The Emotional Construction of Morals is a book about moral judgements – the kinds of mental states we might express by sentences such as, ‘It's bad to flash your neighbors’, or ‘You ought not eat your pets’. There are three basic questions that get addressed: what are the psychological states that constitute such judgements? What kinds of properties do such judgements refer to? And, where do these judgements come from? The first question concerns moral psychology, the second metaethics and the (...) third is best construed as belonging to a domain that has been neglected in analytic value theory: the genealogy of morals. These are all separate branches of ethics, but they are interconnected. The thesis of the book is that moral judgements are emotional attitudes that refer to response-dependent properties, and that these responses have been shaped by cultural history. I call the view Constructive Sentimentalism. The first half of the book deals with sentiments, and the second half with construction. The second half also deals with relativism, because I argue that moral values are constructed differently across cultures and across individuals.Thus described, The Emotional Construction of Morals is a conventional contribution to analytic moral philosophy, taking on some of the core questions in that field and defending positions that have a long philosophical pedigree. Indeed, the theory I defend has roots in Hume and Nietzsche, though it departs from both in various ways. What makes the book somewhat unusual is that it seeks to defend traditional theories by appeal to recent work in psychology, neuroscience, anthropology and related fields. It is an exercise in methodological naturalism and committed to the view that we can answer traditional philosophical questions while treating ethics as a social science. Ethics and naturalism are hard to reconcile because ethics is a normative domain, …. (shrink)

How do we judge whether an action is morally right or wrong? If an action is wrong, what reason does that give us not to do it? Why should we give such reasons priority over our other concerns and values? In this book, T. M. Scanlon offers new answers to these questions, as they apply to the central part of morality that concerns what we owe to each other. According to his contractualist view, thinking about right and wrong is thinking (...) about what we do in terms that could be justified to others and that they could not reasonably reject. He shows how the special authority of conclusions about right and wrong arises from the value of being related to others in this way, and he shows how familiar moral ideas such as fairness and responsibility can be understood through their role in this process of mutual justification and criticism. Scanlon bases his contractualism on a broader account of reasons, value, and individual well-being that challenges standard views about these crucial notions. He argues that desires do not provide us with reasons, that states of affairs are not the primary bearers of value, and that well-being is not as important for rational decision-making as it is commonly held to be. Scanlon is a pluralist about both moral and non-moral values. He argues that, taking this plurality of values into account, contractualism allows for most of the variability in moral requirements that relativists have claimed, while still accounting for the full force of our judgments of right and wrong. (shrink)

Hare has written a clear, brief, and readable introduction to ethics which looks at all the fundamental problems of the subject.

Philosophical discussions of psychopathy have been framed primarily in terms of psychopaths' conspicuous moral shortcomings. But despite their vaunted ‘egocentricity’, another prominent trait in the standard psychopathic profile is a characteristic failure to look after themselves; in an important way, psychopaths appear to be as careless of themselves as they are of others. Assuming that the standard profile is largely correct, the question is how these moral and prudential deficits are related. Are they linked in some non‐accidental way? This paper (...) is a sympathetic exploration and articulation of the hypothesis that psychopathy involves an incapacity for critical distance from from one's own impulses and inclinations, an incapacity that would explain the lack of both prudential and moral regard. (shrink)

R. Jay Wallace argues in this book that moral accountability hinges on questions of fairness: When is it fair to hold people morally responsible for what they do? Would it be fair to do so even in a deterministic world? To answer these questions, we need to understand what we are doing when we hold people morally responsible, a stance that Wallace connects with a central class of moral sentiments, those of resentment, indignation, and guilt. To hold someone responsible, he (...) argues, is to be subject to these reactive emotions in one's dealings with that person. Developing this theme with unusual sophistication, he offers a new interpretation of the reactive emotions and traces their role in our practices of blame and moral sanction. With this account in place, Wallace advances a powerful and sustained argument against the common view that accountability requires freedom of will. Instead, he maintains, the fairness of holding people responsible depends on their rational competence: the power to grasp moral reasons and to control their behavior accordingly. He shows how these forms of rational competence are compatible with determinism. At the same time, giving serious consideration to incompatibilist concerns, Wallace develops a compelling diagnosis of the common assumption that freedom is necessary for responsibility. Rigorously argued, eminently readable, this book touches on issues of broad concern to philosophers, legal theorists, political scientists, and anyone with an interest in the nature and limits of responsibility. (shrink)

Responsibility and the Moral Sentiments offers an account of moral responsibility. It addresses the question: what are the forms of capacity or ability that render us morally accountable for the things we do? A traditional answer has it that the conditions of moral responsibility include freedom of the will, where this in turn involves the availability of robust alternative possibilities. I reject this answer, arguing that the conditions of moral responsibility do not include any condition of alternative possibilities. In the (...) terms that have become familiar, the book thus defends a compatibilist account of moral responsibility. (shrink)

Children are not simply molded by the environment; through constant inference and interpretation, they actively shape their own social world. This book is about that process. Elliot Turiel's work focuses on the development of moral judgment in children and adolescents and, more generally, on their evolving understanding of the conventions of social systems. His research suggests that social judgements are ordered, systematic, subtly discriminative, and related to behavior. His theory of the ways in which children generate social knowledge through their (...) social experiences will be of interest to a wide range of researchers and students in child development and education. (shrink)

I argue that wrongdoers may be open to moral blame even if they lacked the capacity to respond to the moral considerations that counted against their behavior. My initial argument turns on the suggestion that even an agent who cannot respond to specific moral considerations may still guide her behavior by her judgments about reasons. I argue that this explanation of a wrongdoer’s behavior can qualify her for blame even if her capacity for moral understanding is impaired. A second argument (...) is based on the observation that even when a blameworthy wrongdoer could have responded to moral considerations, this is often not relevant to her blameworthiness. Finally, I argue against the view that because blame communicates moral demands, only agents who can be reached by such communication are properly blamed. I contend that a person victimized by a wrongdoer with an impaired capacity for moral understanding may protest her victimization in a way that counts as a form of moral blame even though it does not primarily express a moral demand or attempt to initiate moral dialogue. (shrink)

Abstract: Many philosophers believe that people who are not capable of grasping the significance of moral considerations are not open to moral blame when they fail to respond appropriately to these considerations. I contend, however, that some morally blind, or 'psychopathic,' agents are proper targets for moral blame, at least on some occasions. I argue that moral blame is a response to the normative commitments and attitudes of a wrongdoer and that the actions of morally blind agents can express the (...) relevant blame-grounding attitudes insofar as these agents possess the capacity to make judgments about non-moral reasons. (shrink)

What is the Moral Problem? NORMATIVE ETHICS VS. META-ETHICS It is a common fact of everyday life that we appraise each others' behaviour and attitudes from ...

This paper attempts to provide a more plausible theory of moral accountability and the crucial role in it of moral address by taking seriously four "marginal" cases of agency: psychopaths, moral fetishists, and individuals with autism and mild intellectual disabilities. Each case motivates the addition of another key accountability capacity.

Metaethical questions are typically held to be a priori , and therefore impervious to empirical evidence. Here I examine the metaethical claim that motive-internalism about belief , the position that moral beliefs are intrinsically motivating, is true. I argue that belief-internalists are faced with a dilemma. Either their formulation of internalism is so weak that it fails to be philosophically interesting, or it is a substantive claim but can be shown to be empirically false. I then provide evidence for the (...) falsity of substantive belief-internalism. I describe a group of brain-damaged patients who sustain impairment in their moral sensibility: although they have normal moral beliefs and make moral judgments, they are not inclined to act in accordance with those beliefs and judgments. Thus, I argue that they are walking counterexamples to the substantive internalist claim. In addition to constraining our conception of moral reasoning, this argument stands as an example of how empirical evidence can be relevantly brought to bear on a philosophical question typically viewed to be a priori. (shrink)

Recent work in cognitive science provides overwhelming evidence for a link between emotion and moral judgment. I review findings from psychology, cognitive neuroscience, and research on psychopathology and conclude that emotions are not merely correlated with moral judgments but they are also, in some sense, both necessary and sufficient. I then use these findings along with some anthropological observations to support several philosophical theories: first, I argue that sentimentalism is true: to judge that something is wrong is to have a (...) sentiment of disapprobation towards it. Second, I argue that moral facts are response-dependent: the bad just is that which cases disapprobation in a community of moralizers. Third, I argue that a form of motivational internalism is true: ordinary moral judgments are intrinsically motivating, and all non-motivating moral judgments are parasitic on these. (shrink)

Jesse Prinz argues that recent work in philosophy, neuroscience, and anthropology supports two radical hypotheses about the nature of morality: moral values are based on emotional responses, and these emotional responses are inculcated by culture, not hard-wired through natural selection. In the first half of the book, Jesse Prinz defends the hypothesis that morality has an emotional foundation. Evidence from brain imaging, social psychology, and psychopathology suggest that, when we judge something to be right or wrong, we are merely expressing (...) our emotions. Prinz argues that these emotions do not track objective features of reality; rather, the rightness and wrongness of an act consists in the fact that people are disposed to have certain emotions towards it. In the second half of the book, he turns to a defense of moral relativism. Moral facts depend on emotional responses, and emotional responses vary from culture to culture. Prinz surveys the anthropological record to establish moral variation, and he draws on cultural history to show how attitudes toward practices such as cannibalism and marriage change over time. He also criticizes evidence from animal behavior and child development that has been taken to support the claim that moral attitudes are hard-wired by natural selection. Prinz concludes that there is no single true morality, but he also argues that some moral values are better than others; moral progress is possible. Throughout the book, Prinz relates his views to contemporary and historical work in philosophical ethics. His views echo themes in the writings of David Hume and Friedrich Nietzsche, but Prinz supports, extends, and revises these classic theories using the resources of cutting-edge cognitive science. The Emotional Construction of Morals will stimulate and challenge anyone who is curious about the nature and origin of moral values. (shrink)

Over the last twenty years, a number of central figures in moral philosophy have defended some version of moral rationalism, the idea that morality is based on reason or rationality. According to rationalism, morality is based on reason or rationality rather than the emotions or cultural idiosyncrasies, and this has seemed to many to be the best way of securing a kind of objectivism about moral claims. Consider the following representative statements.

Over the last 20 years, a number of central figures in moral philosophy have defended some version of moral rationalism, the idea that morality is based on reason or rationality (e.g., Gewirth 1978, Darwall 1983, Nagel 1970, 1986, Korsgaard 1986, Singer 1995; Smith 1994, 1997). According to rationalism, morality is based on reason or rationality rather than the emotions or cultural idiosyncrasies, and this has seemed to many to be the best way of securing a kind of objectivism about moral (...) claims. Consider the following representative statements. (shrink)

Psychopaths pose a puzzle. The pleasure they take in the pain of others suggests that they are the paradigms of blameworthiness, while their psychological incapacities provide them with paradigm excuses on plausible accounts of moral responsibility. I begin by assessing two influential responses: one that claims that psychopaths are morally blameworthy in one sense and not in another, and one that takes the two senses of blameworthiness to be inseparable. I offer a new argument that psychopaths, as understood in the (...) debate, are blameworthy in neither sense, while showing how the two senses of blameworthiness nevertheless come apart. (shrink)

Neil Levy (2007) argues that empirical data shows that psychopaths lack the moral knowledge required for moral responsibility. His account is intriguing, and it offers a promising way to think about the significance of psychopaths for work on moral responsibility. In what follows we focus on three lines of concern connected to Levy's account: his interpretation of the data, the scope of exculpation, and the significance of biological explanations for anti-social behavior.

Psychopaths are renowned for their immoral behavior. They are ideal candidates for testing the empirical plausibility of moral theories. Many think the source of their immorality is their emotional deficits. Psychopaths experience no guilt or remorse, feel no empathy, and appear to be perfectly rational. If this is true, sentimentalism is supported over rationalism. Here, I examine the nature of psychopathic practical reason and argue that it is impaired. The relevance to morality is discussed. I conclude that rationalists can explain (...) the moral deficits of psychopaths as well as sentimentalists. In the process, I identify psychological structures that underpin practical rationality. (shrink)

Psychopaths are renowned for their immoral behavior. They are ideal candidates for testing the empirical plausibility of moral theories. Many think the source of their immorality is their emotional deficits. Psychopaths experience no guilt or remorse, feel no empathy, and appear to be perfectly rational. If this is true, sentimentalism is supported over rationalism. Here, I examine the nature of psychopathic practical reason and argue that it is impaired. The relevance to morality is discussed. I conclude that rationalists can explain (...) the moral deficits of psychopaths as well as sentimentalists. In the process, I identify psychological structures that underpin practical rationality. (shrink)

The recent debate over the moral responsibility of psychopaths has centered on whether, or in what sense, they understand moral requirements. In this paper, I argue that even if they do understand what morality requires, the content of their actions is not of the right kind to justify full-blown blame. I advance two independent justifications of this claim. First, I argue that if the psychopath comes to know what morality requires via a route that does not involve a proper appreciation (...) of what it means to cause another harm or distress, the content of violations of rules against harm will be of a lower grade than the content of similar actions by normal individuals. Second, I argue that in order to intend a harm to a person?that is, to intend the distinctive kind of harm that can only befall a person?it is necessary to understand what personhood is and what makes it valuable. The psychopath's deficits with regard to mental time travel ensure that s/he cannot intend this kind of harm. (shrink)

The recent debate over the moral responsibility of psychopaths has centered on whether, or in what sense, they understand moral requirements. In this paper, I argue that even if they do understand what morality requires, the content of their actions is not of the right kind to justify full-blown blame. I advance two independent justifications of this claim. First, I argue that if the psychopath comes to know what morality requires via a route that does not involve a proper appreciation (...) of what it means to cause another harm or distress, the content of violations of rules against harm will be of a lower grade than the content of similar actions by normal individuals. Second, I argue that in order to intend a harm to a person—that is, to intend the distinctive kind of harm that can only befall a person—it is necessary to understand what personhood is and what makes it valuable. The psychopath's deficits with regard to mental time travel ensure that s/he cannot intend this kind of harm. (shrink)

Do psychopaths make moral judgments but lack motivation? Or are psychopaths’ judgments are not genuinely moral? Both sides of this debate seem to assume either externalist or internalist criteria for the presence of moral judgment. However, if moral judgment is a natural kind, we can arrive at a theory-neutral criterion for moral judgment. A leading naturalistic criterion suggests that psychopaths have an impaired capacity for moral judgment; the capacity is neither fully present nor fully absent. Psychopaths are therefore not counterexamples (...) to internalism. Nonetheless, internalism is empirically problematic because it is unable to explain psychopaths’ moral deficits. (shrink)

It is often claimed that the existence of psychopaths undermines moral rationalism. I examine a recent empirically based argument for this claim and conclude that rationalist accounts of moral judgement and moral reasoning are perfectly compatible with the evidence cited.

Psychopaths have long been of interest to moral philosophers, since a careful examination of their peculiar deficiencies may reveal what features are normally critical to the development of moral agency. What underlies the psychopath's amoralism? A common and plausible answer to this question is that the psychopath lacks empathy. Lack of empathy is also claimed to be a critical impairment in autism, yet it is not at all clear that autistic individuals share the psychopath's amoralism. How is empathy characterized in (...) the literature, and how crucial is empathy, so described, to moral understanding and agency? I argue that an examination of moral thinking in high-functioning autistic people supports a Kantian rather than a Humean account of moral agency. (shrink)

© The Author 2017. Published by Oxford University Press on behalf of The Analysis Trust. All rights reserved. For Permissions, please email: [email protected] Shoemaker’s new book, Responsibility from the Margins, is an excellent and insightful explication of Shoemaker’s tripartite theory of moral responsibility. After setting out the main elements of his account, Shoemaker uses underexplored marginal cases of responsible agency to illustrate, support and shape his main theses concerning responsibility. The book as a whole thus presents us with a thoroughly (...) defended, subtle, and plausible theory of the extent and the nature of moral responsibility.Shoemaker takes as his starting point Peter Strawson’s claim that an agent’s responsibility for an action stems from the ‘quality of will’ expressed by that action. In particular, the appropriateness of our reactive attitudes towards an... (shrink)

This paper updates, modifies, and extends an account of psychopaths’ responsibility and blameworthiness that depends on behavioral control rather than moral knowledge. Philosophers mainly focus on whether psychopaths can be said to grasp moral rules as such, whereas it seems to be important to their blameworthiness that typical psychopaths are hampered by impulsivity and other barriers to exercising self-control. I begin by discussing an atypical case, for contrast, of a young man who was diagnosed as a psychopath at one point (...) but who lacks the element of impulsivity. He exhibits the usual deficits of empathy and related moral emotions, but by now he has developed effective alternative means of conforming to moral rules, essentially on the basis of self-interest. I think it does seem reasonable to hold him morally responsible if he should violate a rule, despite his refusal to acknowledge any specifically moral reasons. I then turn to more typical cases, arguing that blameworthiness is mitigated by the difficulty of learning alternative means of self-control. In a departure from my earlier work, I do not take responsibility to have degrees. But since both blameworthiness and freedom to do otherwise have degrees that depend on the same factors, I go on to explain how it can be reasonable to blame a typical psychopath for an act he may not have been free to avoid. More generally, my suggestion is that notions commonly conflated in philosophers’ treatments of responsibility should be prized apart. (shrink)

Psychopaths are agents who lack the normal capacity to feel moral emotions (e.g. guilt based on empathy with the victims of their actions). Evidence for attributing psychopathy at least in some cases to genetic or early childhood causes suggests that psychopaths lack free will. However, the paper defends a sense in which psychopaths still may be construed as responsible for their actions, even if their degree of responsibility is less than that of normal agents. Responsibility is understood in Strawsonian terms, (...) as a question of our appropriate reactive attitudes toward an agent for what she does, and as distinct from the question of the agent's own motivating attitudes, which lead him to do what he does. The latter is the question more directly relevant to free will, though moral motivation normally depends on the capacity in early childhood to pick up motivating attitudes from others' reactive attitudes. Reactive attitudes based on hatred rather than anger (e.g. disgust or contempt) count as alternative forms of blame that may be appropriately directed toward agents manifesting bad qualities of will, even as a matter of motivational impairment. So psychopaths may still be said to deserve blame, even if they are incapable of modifying their behavior in response to blame. (shrink)

The category of emotions covers a disputed territory, but clear examples include fear, anger, joy, pride, sadness, disgust, shame, contempt and the like. Such states are commonly thought of as antithetical to reason, disorienting and distorting practical thought. However, there is also a sense in which emotions are factors in practical reasoning, understood broadly as reasoning that issues in action. At the very least emotions can function as "enabling" causes of rational decision-making (despite the many cases in which they are (...) disabling) insofar as they direct attention toward certain objects of thought and away from others. They serve to heighten memory and to limit the set of salient practical options to a manageable set, suitable for "quick-and-dirty" decision-making. (shrink)

One of the most significant disputes in early modern philosophy was between the moral rationalists and the moral sentimentalists. The moral rationalists — such as Ralph Cudworth, Samuel Clarke and John Balguy — held that morality originated in reason alone. The moral sentimentalists — such as Anthony Ashley Cooper, the third Earl of Shaftesbury, Francis Hutcheson and David Hume — held that morality originated at least partly in sentiment. In addition to arguments, the rationalists and sentimentalists developed rich analogies. The (...) most significant analogy the rationalists developed was between morality and mathematics. The most significant analogy the sentimentalists developed was between morality and beauty. These two analogies illustrate well the main ideas, underlying insights, and accounts of moral phenomenology the two positions have to offer. An examination of the two analogies will thus serve as a useful introduction to the debate between moral rationalism and moral sentimentalism as a whole. (shrink)

The psychopathic personality disorder historically has been thought to include an insensitivity to morality. Some have thought that the psychopath's insensitivity indicates that he does not understand morality, but the relationship between the psychopath's defects and moral understanding has been unclear. We attempt to clarify this relationship, first by arguing that moral understanding is incomplete without concern for morality, and second, by showing that the psychopath demonstrates defects in frontal lobe activity which indicate impaired attention and adaptation to environmental conditions (...) which are relevant to the formation of complex intentions. We argue that these frontal lobe defects can help to explain both the psychopath's apparent insensitivity to morality and his characteristic imprudence. (shrink)

David Shoemaker presents a new pluralistic theory of responsibility, based on the idea of quality of will. His approach is motivated by our ambivalence to real-life cases of marginal agency, such as those caused by clinical depression, dementia, scrupulosity, psychopathy, autism, intellectual disability, and poor formative circumstances. Our ambivalent responses suggest that such agents are responsible in some ways but not others. Shoemaker develops a theory to account for our ambivalence, via close examination of several categories of pancultural emotional responsibility (...) responses and their appropriateness conditions. The result is three distinct types of responsibility, each with its own set of required capacities: attributability, answerability, and accountability. Attributability is about the having and expressing of various traits of character, and it is the target of a range of aretaic sentiments and emotional practices organized around disdain and admiration. Answerability is about one’s capacity to govern one’s actions and attitudes by one’s evaluative judgments about the worth of various practical reasons, and it is the target of a range of sentiments and emotional practices organized around regret and pride. Accountability is about one’s ability to regard others, both evaluatively and emotionally, and it is the target of a range of sentiments and emotional practices organized around anger and gratitude. In Part One of the book, this tripartite theory is developed and defended. In Part Two of the book, the tripartite theory’s predictions about specific marginal cases are tested, once certain empirical details about the nature of those agents have been filled in and discussed. (shrink)

THE FIRST EDITION of this book was based primarily on experience with adult male psychopaths hospitalized in a closed institution. Though a great many other psychopaths had come to my attention, most of the patients who were observed over years and from whom emerged the basic concepts presented in 1941 were from this group. During the next decade a much more diverse group became available. Female patients, adolescents, people who had never been admitted to a psychiatric hospital, all in large (...) numbers, became available for study and afforded an opportunity to observe the disorder in a very wide range of variety and of degree. This additional clinical experience, helpful comment in the reviews of the first edition, enlightening discussion with colleagues, and an improved acquaintance with the literature all contributed to modify concepts formulated approximately ten years earlier. In attempting to revise the book for the second edition (1950), I found it was impossible to do justice to the subject by minor additions, deletions, and modifications. It was necessary to write a new and much larger book. (shrink)