It is shown that, according to NF, many of the assertions of ordinal arithmetic involving the T-function which is peculiar to NF turn out to be equivalent to the truth-in-certain-permutation-models of assertions which have perfectly sensible ZF-style meanings, such as: the existence of wellfounded sets of great size or rank, or the nonexistence of small counterexamples to the wellfoundedness of ∈. Everything here holds also for NFU if the permutations are taken to fix all urelemente.

Recent longitudinal observations show that human menstrual cycles, sleep‐wake cycles and manic‐depressive cycles can become synchronized with lunar cycles, but do so in uniquely complex and heterogeneous ways that are unlikely to have been detected by past studies. Past studies’ negative results have given rise to a scientific consensus that human biology and behavior are unaffected by lunar cycles. The recent observations show that synchrony can be temporary, and can occur with more than one type of lunar cycle, more than (...) one phase of a lunar cycle and more than one resonant frequency of a lunar cycle. Given the variability of human responses to lunar cycles, aggregate analyses used in almost all previous studies would likely have cancelled out individuals’ responses and led to false negative results. In light of these observations, the question of lunar influence should be investigated further, with longitudinal observations and case‐by‐case analyses of individuals’ data. (shrink)

A version of the Erdös-Rado theorem on partitions of the unordered n-tuples from uncountable sets is proved, without using the axiom of choice. The case with exponent 1 is just the Sierpinski-Hartogs' result that $\aleph (\alpha)\leq 2^{2^{2^{\alpha}}}$.

The phrase ‘The iterative conception of sets’ conjures up a picture of a particular settheoretic universe – the cumulative hierarchy – and the constant conjunction of phrasewith-picture is so reliable that people tend to think that the cumulative hierarchy is all there is to the iterative conception of sets: if you conceive sets iteratively, then the result is the cumulative hierarchy. In this paper, I shall be arguing that this is a mistake: the iterative conception of set is a good (...) one, for all the usual reasons. However, the cumulative hierarchy is merely one way among many of working out this conception, and arguments in favour of an iterative conception have been mistaken for arguments in favour of this one special instance of it. (This may be the point to get out of the way the observation that although philosophers of mathematics write of the iterative conception of set, what they really mean – in the terminology of modern computer science at least – is the recursive conception of sets. Nevertheless, having got that quibble off my chest, I shall continue to write of the iterative conception like everyone else.). (shrink)

We shed light on an old problem by showing that the logic LP cannot define a binary connective $\odot$ obeying detachment in the sense that every valuation satisfying $\varphi$ and $(\varphi\odot\psi)$ also satisfies $\psi$ , except trivially. We derive this as a corollary of a more general result concerning variable sharing.

Sharvy’s puzzle concerns a situation in which common knowledge of two parties is obtained by repeated observation each of the other, no fixed point being reached in finite time. Can a fixed point be reached?

Let ZFB be ZF + "every set is the same size as a wellfounded set". Then the following are true. Every sentence true in every (Rieger-Bernays) permutation model of a model of ZF is a theorem of ZFB. (i.e.. ZFB is the theory of Rieger-Bernays permutation models of models of ZF) ZF and ZFAFA are both extensions of ZFB conservative for stratified formulæ. The class of models of ZFB is closed under creation of Rieger-Bernays permutation models.

We consider the quantifier hierarchy of Takahashi [1972] and show how it gives rise to reflection theorems for some large cardinals in ZF, a new natural subtheory of Zermelo's set theory, a potentially useful new reduction of the consistency problem for Quine's NF, and a sharpening of another reduction of this problem due to Boffa.

Many mathematical objects arise from equivalence classes and invite implementation as those classes. Set-existence principles that would enable this are incompatible with ZFC's unrestricted aussonderung but there are set theories which admit more instances than does ZF. NF provides equivalence classes for stratified relations only. Church's construction provides equivalence classes for “low” sets, and thus, for example, a set of all ordinals. However, that set has an ordinal in turn which is not a member of the set constructed; so no (...) set of all ordinals is obtained thereby. This “recurrence problem” is discussed. (shrink)

Many mathematical objects arise from equivalence classes and invite implementation as those classes. Set-existence principles that would enable this are incompatible with ZFC's unrestricted _aussonderung_ but there are set theories which admit more instances than does ZF. NF provides equivalence classes for stratified relations only. Church's construction provides equivalence classes for "low" sets, and thus, for example, a set of all ordinals. However, that set has an ordinal in turn which is not a member of the set constructed; so no (...) set of _all_ ordinals is obtained thereby. This "recurrence problem" is discussed. (shrink)

In general little thought is given to the general question of how to implement mathematical objects in set theory. It is clear that—at various times in the past—people have gone to considerable lengths to devise implementations with nice properties. There is a litera- ture on the evolution of the Wiener-Kuratowski ordered pair, and a discussion by Quine of the merits of an ordered-pair implemen- tation that makes every set an ordered pair. The implementation of ordinals as Von Neumann ordinals is (...) so attractive that it is uni- versally used in all set theories which have enough replacement to prove Mostowski’s collapse lemma. I have frequently complained in the past about the widespread habit of referring to implementations of pairs (ordinals etc) as definitions of pairs (etc). My point here is a different one: generally little attention has been paid to the question of what makes an implementation a good implementation. In most cases of interest the merits of the candidates are uncontroversial. What I want to examine here is an example where there are com- peting implementations for ordered pairs, and—although it is clear to the cognoscenti and also (with a bit of arm-waving) plausible to the logician in the street that some of the impossible candidates are impossible, nobody has ever given a satisfactory explanation of why this is so. (shrink)

As such this book fills a void in the philosophical literature and presents a challenge to every would-be (anti-)reductionist.

It is shown in ZF (without choice) that if there is a finite-to-one map P(X) → X, then X is finite.

We present an order-theoretic analysis of set-theoretic paradoxes. This analysis will show that a large variety of purely set-theoretic paradoxes (including the various Russell paradoxes as well as all the familiar implementations of the paradoxes of Mirimanoff and Burali-Forti) are all instances of a single limitative phenomenon.

Sharvy’s puzzle concerns a situation in which common knowledge of two parties is obtained by repeated observation each of the other, no fixed point being reached in finite time. Can a fixed point be reached?

We identify complete fragments of the simple theory of types with infinity and Quine’s new foundations set theory. We show that TSTI decides every sentence ϕ in the language of type theory that is in one of the following forms: ϕ=∀x1r1⋯∀xkrk∃y1s1⋯∃ylslθ where the superscripts denote the types of the variables, s1>⋯>sl, and θ is quantifier-free, ϕ=∀x1r1⋯∀xkrk∃y1s⋯∃ylsθ where the superscripts denote the types of the variables and θ is quantifier-free. This shows that NF decides every stratified sentence ϕ in the language (...) of set theory that is in one of the following forms: ϕ=∀x1⋯∀xk∃y1⋯∃ylθ where θ is quantifier-free and ϕ admits a stratification that assigns distinct values to all of the variables y1,…,yl, ϕ=∀x1⋯∀xk∃y1⋯∃ylθ where θ is quantifier-free and ϕ admits a stratification that assigns the same value to all of the variables y1,…,yl. (shrink)

A.P. Martinich's interpretation that in Leviathan Thomas Hobbes believed that the laws of nature are the commands of God and that he did not rely on the Bible to prove this has been criticized by Greg Forster in this journal (2003). Forster uses these criticisms to develop his own view that Hobbes was insincere when he professed religious beliefs. We argue that Forster misrepresents Martinich's view, is mistaken about what evidence is relevant to interpreting whether Hobbes (...) was sincere or not, and is mistaken about some of Hobbes's central doctrines. Forster's criticisms are worth discussing at length for at least three reasons. He takes the debate about Hobbes's sincerity to a new level of sophistication; his misinterpretations of Hobbes may become accepted as correct; and his criticisms raise issues about the proper method of interpreting historical texts. (shrink)

The subtlety of the novel lies in its unrelieved tension of flesh and spirit, exclusion and invitation, the social self and the deeper impersonal self. At one extreme are the caricatures caught in the social grid - the Turtons and Burtons. At the other are the characters who slip out of the meshes of social responsibility through despair or obliviousness. We move from the elaborate rituals of Anglo-Indian to Mau, where the only aspects of life we are shown are ecstasy (...) and neglect. Where does the mind rest? The difficulty with looking at reality directly is that reality will tend to dissolve: "not now, not here, not to be apprehended except when it is unattainable." Transcendence dehumanizes, the deeper self is a source rather than a habitation, we cannot see the unseen. We only glimpse it through paradox, violence, or farce; and each of these contributes something to Forster's conception of character. Martin Price, Thomas E. Donnelly Professor of English at Yale University, is author of To the Palace of Wisdom and the recently reprinted Swift's Rhetorical Art, editor and coeditor of the Oxford Anthology of English Literature, and coeditor of Poetry Past and Present. He is currently working on a book on character in the novel. (shrink)

Scientific discovery is often regarded as romantic and creative - and hence unanalyzable - whereas the everyday process of verifying discoveries is sober and more suited to analysis. Yet this fascinating exploration of how scientific work proceeds argues that however sudden the moment of discovery may seem, the discovery process can be described and modeled. Using the methods and concepts of contemporary information-processing psychology (or cognitive science) the authors develop a series of artificial-intelligence programs that can simulate the human thought (...) processes used to discover scientific laws. The programs - BACON, DALTON, GLAUBER, and STAHL - are all largely data-driven, that is, when presented with series of chemical or physical measurements they search for uniformities and linking elements, generating and checking hypotheses and creating new concepts as they go along. "Scientific Discovery examines the nature of scientific research and reviews the arguments for and against a normative theory of discovery; describes the evolution of the BACON programs, which discover quantitative empirical laws and invent new concepts; presents programs that discover laws in qualitative and quantitative data; and ties the results together, suggesting how a combined and extended program might find research problems, invent new instruments, and invent appropriate problem representations. Numerous prominent historical examples of discoveries from physics and chemistry are used as tests for the programs and anchor the discussion concretely in the history of science. Pat Langley is an Associate Professor in the Department of Information and Computer Science at the University of California, Irvine.Herbert Simon is a Professor in the Departments of Psychology, Computer Science, and Philosophy at Carnegie-Mellon University. Gary L. Bradshaw is an Assistant Professor in the Department of Psychology and Institute of Cognitive Science at the University of Colorado, Boulder. Jan M. Zytkow is an Associate Professor in the Computer Science Department at Wichita State University. (shrink)

v. 1. Editorial introduction -- v. 2. The English and Latin texts (i) -- v. 3. The English and Latin texts (ii).

The newly updated Right and Wrong 2nd Edition is an accessible introduction to the major traditions in western philosophical ethics, written in a lively and engaging style. It is designed for entry-level ethics courses and includes real-life ethical scenarios chosen to appeal directly to students. Greatly expanded and improved, this successful text introduces students to the major ethical traditions, and provides a simple methodology for resolving ethical dilemmas Treats teleological and deontological approaches to ethics as the two most important traditions, (...) but now includes chapters on virtue ethics and the ethics of care The very accessible writing style speaks directly to students’ own experience Draws examples from three types of real-life ethical scenarios submitted by students: academic dishonesty, partying, and personal relationships Provides a concise treatment of this notoriously complex subject, perfect for entry-level ethics and applied ethics courses. (shrink)

When making decisions, humans can observe many kinds of information about others' activities, but their effects on performance are not well understood. We investigated social learning strategies using a simple problem-solving task in which participants search a complex space, and each can view and imitate others' solutions. Results showed that participants combined multiple sources of information to guide learning, including payoffs of peers' solutions, popularity of solution elements among peers, similarity of peers' solutions to their own, and relative payoffs from (...) individual exploration. Furthermore, performance was positively associated with imitation rates at both the individual and group levels. When peers' payoffs were hidden, popularity and similarity biases reversed, participants searched more broadly and randomly, and both quality and equity of exploration suffered. We conclude that when peers' solutions can be effectively compared, imitation does not simply permit scrounging, but it can also facilitate propagation of good solutions for further cumulative exploration. (shrink)

It is somewhat misleading to think of the Franciscans as forming a “school” in ethics, since there was a fair bit of diversity among Franciscans. Nonetheless, one can identify certain characteristic tendencies of Franciscan moral thought, and certain “celebrity” Franciscans whose views in ethics and moral psychology are particularly noteworthy. I shall first offer an overview of the general character of Franciscan moral thought in the late thirteenth and early fourteenth centuries and then turn to a more detailed examination of (...) the thought of John Duns Scotus (1265/66-1308) and William Ockham (c. 1288-1347) on three central matters of debate: the nature of the virtues, the relationship between intellect and will, and the relationship between moral requirements and the divine will. (shrink)

In this book Thomas Wren uncovers and assesses the largely hidden philosophical assumptions about human motivation that have shaped contemporary psychological ...

The relativist strain in Rorty’s work should be distinguished from the Davidsonian strain. The latter may be exploited in support of Rorty’s critique of philosophy but it is at odds with his use of “solidarity” and “ethnocentrism”as explanatory concepts. Once this is recognized, there remains in Rorty’s work a consistent challenge to the search for general philosophical theories of truth, objectivity, and rationality (of which relativism itself is an example). On this reading, however, Rorty’s pragmatism is not a theory that (...) offers answers to questions about the authority of beliefs and practices but rather a critical tool used to open detailed, concrete, and critical investigation into particular questions about the establishment and viability of the beliefs and practices we have. (shrink)