Princeton University Press, 1974. This book is out of print, but can be downloaded as a pdf file (5 MB).

There was a long tradition in philosophy according to which good reasoning had to be deductively valid. However, that tradition began to be questioned in the 1960’s, and is now thoroughly discredited. What caused its downfall was the recognition that many familiar kinds of reasoning are not deductively valid, but clearly confer justification on their conclusions. Here are some simple examples.

Princeton University Press, 984. This book is out of print, but can be downloaded as a pdf file (3.9 MB).

An argument is self-defeating when it contains defeaters for some of its own defeasible lines. It is shown that the obvious rules for defeat among arguments do not handle self-defeating arguments correctly. It turns out that they constitute a pervasive phenomenon that threatens to cripple defeasible reasoning, leading to almost all defeasible reasoning being defeated by unexpected interactions with self-defeating arguments. This leads to some important changes in the general theory of defeasible reasoning.

In a number of recent papers I have been developing the theory of "nomic probability," which is supposed to be the kind of probability involved in statistical laws of nature. One of the main principles of this theory is an acceptance rule explicitly designed to handle the lottery paradox. This paper shows that the rule can also handle the paradox of the preface. The solution proceeds in part by pointing out a surprising connection between the paradox of the preface and (...) the gambler's fallacy. (shrink)

Presenting an analytical and critical study of the contemporary adult educator, Paulo Freire, this book deals with all aspects of his thought, placing at the centre of consideration his educational philosophy.

For this second edition, the editors have returned to Austin's original lecture notes, amending the printed text where it seemed necessary.

Hermann Weyl, one of the twentieth century's greatest mathematicians, was unusual in possessing acute literary and philosophical sensibilities—sensibilities to which he gave full expression in his writings. In this paper I use quotations from these writings to provide a sketch of Weyl's philosophical orientation, following which I attempt to elucidate his views on the mathematical continuum, bringing out the central role he assigned to intuition.

Georges Sorel's reputation as a proponent of violence has helped to link his ideas to fascist and totalitarian thought. Much of the literature on Sorel as developed this theme, at the expense of what Sorel himself stated as his primary purpose, "the discovery of the historical genesis of morals." How, Sorel asked, in the light of the development of modern industry and the vast powers of the modern state the individual can possess a sense of self-worth and at the same (...) time help to sustain a cultural vitality similar to the great societies of antiquity? How is it possible to avoid the utter resignation and nihilistic relativism of modern existence? In his writings Sorel outlined a sociology of virtue that combined the importance of family love as the basis of community feelings with acceptance of the basis of individual vitality as constant industrial struggle against nature. Sorel's solution is different from Marx's: in place of the ida of transcended alienation, Sorel envisions an agonal striving against nature's unceasing resistance to our efforts. The Feuerbachian unity of nature that, for Marx, had been alienated under capitalism, Sorel regarded as being inherently fragmented by scientific procedures themselves, as well as by the industrial processes that correspond to those scientific procedures. For Sorel, the struggle against nature is the struggle that enables man to overcome himself, to strive against his own inclination to passivity, sloth, and licentiousness. The Marxist concept of totality so necessary to the vision of a communist society is rejected, in favor of a pragmatic, pluralist view of nature that parallels the social pluralism of a regime of workers' syndicates. The primary function of Sorel's famous "myth of the general strike" is to link the workers' constant struggles against capitalist employers to the never-ending struggle against nature. The feelings engendered by such a strubble constitute the true core of socialism; without such feelings, socialism is doomed to the same decay that Sorel and Marx foresaw for capitalist civilization. This title is part of UC Press's Voices Revived program, which commemorates University of California Press’s mission to seek out and cultivate the brightest minds and give them voice, reach, and impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1981. (shrink)

IN THEIR WELL-KNOWN PAPER, Kochen and Specker (1967) introduce the concept of partial Boolean algebra (pBa) and show that certain (finitely generated) partial Boolean algebras arising in quantum theory fail to possess morphisms to any Boolean algebra (we call such pBa's intractable in the sequel). In this note we begin by discussing partial..

Reliabilist theories propose to analyse epistemic justification in terms of reliability. This paper argues that if we pay attention to the details of probability theory we find that there is no concept of reliability that can possibly play the role required by reliabilist theories. A distinction is drawn between the general reliability of a process and the single case reliability of an individual belief, And it is argued that neither notion can serve the reliabilist adequately.

It’s morning. You sit down at your desk, cup of coffee in hand, and prepare to begin your day. First, you turn on your computer. Once it is running, you check your e-mail. Having decided it is all spam, you trash it. You close the window on your e-mail program, but leave the program running so that it will periodically check the mail server to see whether you have new mail. If it finds new mail it will alert you by (...) playing a musical tone. Next you start your word processor. You have in mind to write a paper in moral philosophy about whether people who send spam deserve capital punishment. So you open a new window and type several paragraphs of text into it. You like what you wrote, so you save it, creating a file. Later, you have more thoughts about spam and capital punishment, so you open the file again and make some changes. Then it is time to go to class. You turn off your word processor, but leave your computer running so that your email program can collect your e-mail. This mundane sequence of events can seem philosophically puzzling when we think about it carefully. While in your word processor, you opened several windows, entered text into them, and created files. What sorts of things are these files, windows, and text? It might seem that windows are easy to understand. You can, after all, see windows. That is the whole point of them. You see a window by seeing a pattern on the surface of your monitor. Isn’t the window identical with that physical pattern? But that is too quick. First, you can turn your monitor off. The window is still open. You can type text into it, and if you turn the monitor back on you can verify that you made that change. Second, you can drag another window in front of the original window. The original window disappears from view, but it still exists. Things may be happening in it that you cannot see. For example, if it is an e-mail window, new messages may be listed in it as they are 1 downloaded.. (shrink)

It has long been claimed that Homo sapiens is the only species that has language, but only recently has it been recognized that humans also have an unusual pattern of growth and development. Social mammals have two stages of pre-adult development: infancy and juvenility. Humans have two additional prolonged and pronounced life history stages: childhood, an interval of four years extending between infancy and the juvenile period that follows, and adolescence, a stage of about eight years that stretches from juvenility (...) to adulthood. We begin by reviewing the primary biological and linguistic changes occurring in each of the four pre-adult ontogenetic stages in human life history. Then we attempt to trace the evolution of childhood and juvenility in our hominin ancestors. We propose that several different forms of selection applied in infancy and childhood; and that, in adolescence, elaborated vocal behaviors played a role in courtship and intrasexual competition, enhancing fitness and ultimately integrating performative and pragmatic skills with linguistic knowledge in a broad faculty of language. A theoretical consequence of our proposal is that fossil evidence of the uniquely human stages may be used, with other findings, to date the emergence of language. If important aspects of language cannot appear until sexual maturity, as we propose, then a second consequence is that the development of language requires the whole of modern human ontogeny. Our life history model thus offers new ways of investigating, and thinking about, the evolution, development, and ultimately the nature of human language. (shrink)

subsets X of A for which ∃x (x ∈ A). The set of functions from A to B is denoted by BA.

Perkins, John L The atrocity of September 11 led me to become an atheist. A boundary had been crossed, I thought, and religions could no longer be regarded as benign. As the buildings crashed to the ground in New York, this conclusion seemed obvious. Yet a decade and a half later, it seems remarkable how few people have been able to reach the same conclusion.

This new edition of the classic Contemporary Theories of Knowledge has been significantly updated to include analyses of the recent literature in epistemology.

Probability is sometimes regarded as a universal panacea for epistemology. It has been supposed that the rationality of belief is almost entirely a matter of probabilities. Unfortunately, those philosophers who have thought about this most extensively have tended to be probability theorists first, and epistemologists only secondarily. In my estimation, this has tended to make them insensitive to the complexities exhibited by epistemic justification. In this paper I propose to turn the tables. I begin by laying out some rather simple (...) and uncontroversial features of the structure of epistemic justification, and then go on to ask what we can conclude about the connection between epistemology and probability in the light of those features. My conclusion is that probability plays no central role in epistemology. This is not to say that probability plays no role at all. In the course of the investigation, I defend a pair of probabilistic acceptance rules which enable us, under some circumstances, to arrive at justified belief on the basis of high probability. But these rules are of quite limited scope. The effect of there being such rules is merely that probability provides one source for justified belief, on a par with perception, memory, etc. There is no way probability can provide a universal cure for all our epistemological ills. (shrink)

Perkins, John L With his regular programmes on radio and television, newspaper columns and commentary, Waleed Aly has become Australia's favourite Muslim celebrity. He is intelligent, articulate and provides incisive analysis of political and social issues. Given this, it might have been expected that he could have applied the same quality of analysis in his book, People Like Us: How Arrogance is Dividing Islam and the West (2007); however this is not the case.

From unemployment to Brexit to climate change, capitalism is in trouble and ill-prepared to cope with the challenges of the coming decades. How did we get here? While contemporary economists and policymakers tend to ignore the political and social dimensions of capitalism, some of the great economists of the past - Adam Smith, Friedrich List, John Maynard Keynes, Joseph Schumpeter, Karl Polanyi and Albert Hirschman - did not make the same mistake. Leveraging their insights, sociologists John L. Campbell (...) and John A. Hall trace the historical development of capitalism as a social, political, and economic system throughout the twentieth and early twenty-first centuries. They draw comparisons across eras and around the globe to show that there is no inevitable logic of capitalism. Rather, capitalism's performance depends on the strength of nation-states, the social cohesion of capitalist societies, and the stability of the international system - three things that are in short supply today. (shrink)

The strategy of this paper is to throw light on rational cognition and epistemic justification by examining irrationality. Epistemic irrationality is possible because we are reflexive cognizers, able to reason about and redirect some aspects of our own cognition. One consequence of this is that one cannot give a theory of epistemic rationality or epistemic justification without simultaneously giving a theory of practical rationality. A further consequence is that practical irrationality can affect our epistemic cognition. I argue that practical irrationality (...) derives from a general difficulty we have in overriding built-in shortcut modules aimed at making cognition more efficient, and all epistemic irrationality can be traced to this same source. A consequence of this account is that a theory of rationality is a descriptive theory, describing contingent features of a cognitive architecture, and it forms the core of a general theory of “voluntary” cognition — those aspects of cognition that are under voluntary control. It also follows that most of the so-called “rules for rationality” that philosophers have proposed are really just rules describing default (non- reflexive) cognition. It can be perfectly rational for a reflexive cognizer to break these rules. The “normativity” of rationality is a reflection of a built-in feature of reflexive cognition — when we detect violations of rationality, we have a tendency to desire to correct them. This is just another part of the descriptive theory of rationality. Although theories of rationality are descriptive, the structure of reflexive cognition gives philosophers, as human cognizers, privileged access to certain aspects of rational cognition. Philosophical theories of rationality are really scientific theories, based on inference to the best explanation, that take contingent introspective data as the evidence to be explained. (shrink)

This essay presents analogies between the development of historical writing and of physical science during the early modern period. Its necessarily spotty coverage runs from the mid sixteenth century to the beginning of the eighteenth. The analogies include arising from practical concerns; preferring material documents and experimental inquiries over texts; making use of mathematical auxiliary sciences; distinguishing between primary and secondary elements; establishing new fundamental principles; undermining the traditional world system; and devising methods to control rapidly multiplying knowledge. A history (...) of learning that meets today's standards of historical scholarship should identify and exploit such parallels, not only because of scholarly interest and responsibility, but also because an understanding of the historical importance of linkages between distant branches of learning may help redress the increasing imbalance in resources among the natural sciences, the social sciences, and the humanities in our higher schools and universities. (shrink)

Axioms for the continuum, or smooth real line R. These include the usual axioms for a commutative ring with unit expressed in terms of two operations + and i , and two distinguished elements 0 ≠ 1. In addition we stipulate that R is a local ring, i.e., the following axiom: ∃y x i y = 1 ∨ ∃y (1 – x) i y = 1. Axioms for the strict order relation < on R. These are: 1. a < b (...) and b < c implies a < c. 2. ¬(a < a) 3. a < b implies a + c < b + c for any c. ≤ 4. a < b and 0 < c implies acbc.. (shrink)

This essay is an attempt to sketch the evolution of type theory from its beginnings early in the last century to the present day. Central to the development of the type concept has been its close relationship with set theory to begin with and later its even more intimate relationship with category theory. Since it is effectively impossible to describe these relationships (especially in regard to the latter) with any pretensions to completeness within the space of a comparatively short article, (...) I have elected to offer detailed technical presentations of just a few important instances. (shrink)

It has long been asserted that the evolutionary path to spoken language was paved by manual–gestural behaviors, a claim that has been revitalized in response to recent research on mirror neurons. Renewed interest in the relationship between manual and vocal behavior draws attention to its development. Here, the pointing and vocalization of 16.5-month-old infants are reported as a function of the context in which they occurred. When infants operated in a referential mode, the frequency of simultaneous vocalization and pointing exceeded (...) the frequency of vocalization-only and pointing-only responses by a wide margin. In a non-communicative context, combinatorial effects persisted, but in weaker form. Manual–vocal signals thus appear to express the operation of an integrated system, arguably adaptive in the young from evolutionary times to the present. It was speculated, based on reported evidence, that manual behavior increases the frequency and complexity of vocal behaviors in modern infants. There may be merit in the claim that manual behavior facilitated the evolution of language because it helped make available, early in development, behaviors that under selection pressures in later ontogenetic stages elaborated into speech. (shrink)

This book is written for those who are in sympathy with its spirit. This spirit is different from the one which informs the vast stream of European and American civilization in which all of us stand. That spirit expresses itself in an onwards movement, in building ever larger and more complicated structures; the other in striving in clarity and perspicuity in no matter what structure. The first tries to grasp the world by way of its periphery—in its variety; the second (...) at its centre—in its essence. And so the first adds one construction to another, moving on and up, as it were, from one thing to the next, while the other remains where it is and what it tries to grasp is always the same. (shrink)

Pollock describes an exciting theory of rationality and its partial implementation in OSCAR, a computer system whose descendants will literally be persons.