Lionel Penrose (1898–1972) was an important leader during the mid-20th century decline of eugenics and the development of modern medical genetics. However, historians have paid little attention to his radical theoretical challenges to mainline eugenic concepts of mental disease. Working from a classification system developed with his colleague, E. O. Lewis, Penrose developed a statistically sophisticated and clinically grounded refutation of the popular position that low intelligence is inherently a disease state. In the early 1930s, Penrose (...) advocated dividing “mental defect” (low intelligence) into two categories: “pathological mental defect,” which is a disease state that can be traced to a distinct genetic or environmental cause, and “subcultural mental defect,” which is not an inherent disease state, but rather a statistically necessary manifestation of human variation in intelligence. I explore the historical context and theoretical import of this contribution, discussing its rejection of typological thinking and noting that it preceded Theodosius Dobzhansky’s better-known defense of human diversity. I illustrate the importance of Penrose’s contribution with a discussion of an analogous situation in contemporary medicine, the controversial practice of using human growth hormone injections to treat “idiopathic short stature” (mere diminutive height, with no distinct cause). I show how Penrose’s contributions to understanding human variation make such treatments appear quite misguided. (shrink)

Professor Sir Roger Penrose's work, spanning fifty years of science, with over five thousand pages and more than three hundred papers, has been collected together for the first time and arranged chronologically over six volumes, each with an introduction from the author. Where relevant, individual papers also come with specific introductions or notes. The first volume covers the beginnings of a career that is ground-breaking from the outset. Inspired by courses given by Dirac and Bondi, much of the early (...) published work involves linking general relativity with tensor systems. Among his early works is the seminal 1955 paper, 'A Generalized Inverse for Matrices', his previously unpublished PhD and St John's College Fellowship theses, and from 1967, his Adam's Prize-winning essay on the structure of space-time. Add to this his 1965 paper, 'Gravitational collapse and space-time singularities', and the 1967 paper that introduced a remarkable new theory, 'Twistor algebra', and this becomes a truly stellar procession of works on mathematics and cosmology. (shrink)

Professor Sir Roger Penrose's work, spanning fifty years of science, with over five thousand pages and more than three hundred papers, has been collected together for the first time and arranged chronologically over six volumes, each with an introduction from the author. Where relevant, individual papers also come with specific introductions or notes. Many important realizations concerning twistor theory occurred during the short period of this third volume, providing a new perspective on the way that mathematical features of the (...) complex geometry of twistor theory relate to actual physical fields. Following on from the nonlinear graviton construction, a twistor construction was found for (anti-)self-dual electromagnetism allowing the general (anti-)self-dual Yang-Mills field to be obtained. It became clear that some features of twistor contour integrals could be understood in terms of holomorphic sheaf cohomology. During this period, the Oxford research group founded the informal publication, Twistor Newsletter. This volume also contains the influential Weyl curvature hypothesis and new forms of Penrose tiles. (shrink)

Professor Sir Roger Penrose's work, spanning fifty years of science, with over five thousand pages and more than three hundred papers, has been collected together for the first time and arranged chronologically over six volumes, each with an introduction from the author. Where relevant, individual papers also come with specific introductions or notes. Among the new developments that occurred during this period was the introduction of a particular notion of 'quasi-local mass-momentum and angular momentum', the topic of Penrose's (...) Royal Society paper. Many encouraging results were initially obtained but, later, difficulties began to emerge and remain today. Also, an extensive paper (with Eastwood and Wells) gives a thorough account of the relation between twistor cohomology and massless fields. This volume witnesses Penrose's increasing conviction that the puzzling issue of quantum measurement could only be resolved by the appropriate unification of quantum mechanics with general relativity, where that union must involve an actual change in the rules of quantum mechanics as well as in space-time structure. Penrose's first incursions into a possible relation between consciousness and quantum state reduction are also covered here. (shrink)

Professor Sir Roger Penrose's work, spanning fifty years of science, with over five thousand pages and more than three hundred papers, has been collected together for the first time and arranged chronologically over six volumes, each with an introduction from the author. Where relevant, individual papers also come with specific introductions or notes. Publication of The Emperor's New Mind (OUP 1989) had caused considerable debate and Penrose's responses are included in this volume. Arising from this came the idea (...) that large-scale quantum coherence might exist within the conscious brain, and actual conscious experience would be associated with a reduction of the quantum state. Within this collection, Penrose also proposes that a twistor might usefully be regarded as a source (or 'charge') for a massless field of spin 3/2, suggesting that the twistor space for a Ricci-flat space-time might actually be the space of such possible sources. Towards the end of the volume, Penrose begins to develop a quite different approach to incorporating full general relativity into twistor theory. This period also sees the origin of the Diósi-Penrose proposal. (shrink)

Professor Sir Roger Penrose's work, spanning fifty years of science, with over five thousand pages and more than three hundred papers, has been collected together for the first time and arranged chronologically over six volumes, each with an introduction from the author. Where relevant, individual papers also come with specific introductions or notes. Developing ideas sketched in the first volume, twistor theory is now applied to genuine issues of physics, and there are the beginnings of twistor diagram theory (an (...) analogue of Feynman Diagrams). This collection includes joint papers with Stephen Hawking, and uncovers certain properties of black holes. The idea of cosmic censorship is also first proposed. Along completely different lines, the first methods of aperiodic tiling for the Euclidean plane that come to be known as Penrose tiles are described. This volume also contains Penrose's three prize-winning essays for the Gravity Foundation (two second places with both Ezra Newman and Steven Hawking, and a solo first place for 'The Non-linear graviton'). (shrink)

Surveys Western literature and thought to reveal the evolution of the ideals of sincerity and authenticity.

In his bestselling work of popular science, Sir Roger Penrose takes us on a fascinating roller-coaster ride through the basic principles of physics, cosmology, mathematics, and philosophy to show that human thinking can never be emulated by a machine.

Professor Sir Roger Penrose's work, spanning fifty years of science, with over five thousand pages and more than three hundred papers, has been collected together for the first time and arranged chronologically over six volumes, each with an introduction from the author. Where relevant, individual papers also come with specific introductions or notes. This sixth volume describes an actual experiment to measure the length of time that a quantum superposition might last (developing the Diósi-Penrose proposal). It also discusses (...) the significant progress made in relation to incorporating the 'googly' information for a gravitational field into the structure of a curved twistor space. Penrose also covers such things as the geometry of light rays in relation to twistor-space structures, the utility of complex numbers in drawing three-dimensional shapes, and the geometrical representation of different types of musical scales. The turn of the millennium was also an opportunity to reflect on progress in many areas up until that point. (shrink)

Professor Sir Roger Penrose is one of the truly original thinkers of our time. He has made several remarkable contributions to science, from quantum physics and theories of human consciousness to relativity theory and observations on the structure of the universe. Unusually for a scientist, some of his ideas have crossed over into the public arena. Now his work, spanning fifty years of science, with over five thousand pages and more than three hundred papers, has been collected together for (...) the first time and arranged chronologically over six volumes, each with an introduction from the author. Where relevant, individual papers also come with specific introductions or notes. (shrink)

This book, collecting his most important papers in the form in which they were originally published, can be seen as a companion to that one.

Winner of the Wolf Prize for his contribution to our understanding of the universe, Penrose takes on the question of whether artificial intelligence will ever ...

The revisionary approach to semantic paradox is commonly thought to have a somewhat uncomfortable corollary, viz. that, on pain of triviality, we cannot affirm that all valid arguments preserve truth (Beall2007, Beall2009, Field2008, Field2009). We show that the standard arguments for this conclusion all break down once (i) the structural rule of contraction is restricted and (ii) how the premises can be aggregated---so that they can be said to jointly entail a given conclusion---is appropriately understood. In addition, we briefly rehearse (...) some reasons for restricting structural contraction. (shrink)

This volume relates to natural philosophy apart from the study of living things. Topics covered include the principles of scientific inquiry, place, time, motion, the heavens, the sublunary world, meteorology and the study of materials.

Presenting a look at the human mind's capacity while criticizing artificial intelligence, the author makes suggestions about classical and quantum physics and ..

The Cambridge Histories of philosophy, extending from Thales to the seventeenth century, are not a formal series. Nevertheless, they have a distinctive character: authoritative accounts that combine general coverage of a period with the individual contributions of their authors and indicate scholarly controversies. This volume is a worthy continuation of the tradition.

A decade in the making, the _Handbook i_s the definitive contemporary exposition of interpersonal psychoanalysis. It provides an authoritative overview of development, psychopathology, and treatment as conceptualized from the interpersonal viewpoint.

The Hellenistic philosophers and schools of philosophy are emerging from the shadow of Plato and Aristotle and are increasingly studied for their intrinsic philosophical value. They are not only interesting in their own right, but also form the intellectual background of the late Roman Republic. This study gives a comprehensive and readable account of the principal doctrines of the Stoics, Epicureans and various sceptical traditions from the death of Alexander the Great in 323 B.C. to around 200 A.D. Discussions are (...) arranged topically in order to address underlying issues and to make clear what the different schools have in common and how they differ. At the same time the coherence of each system as a whole is emphasized. (shrink)

“Curry’s paradox”, as the term is used by philosophers today, refers to a wide variety of paradoxes of self-reference or circularity that trace their modern ancestry to Curry (1942b) and Löb (1955). The common characteristic of these so-called Curry paradoxes is the way they exploit a notion of implication, entailment or consequence, either in the form of a connective or in the form of a predicate. Curry’s paradox arises in a number of different domains. Like Russell’s paradox, it can take (...) the form of a paradox of set theory or the theory of properties. But it can also take the form of a semantic paradox, closely akin to the Liar paradox. Curry’s paradox differs from both Russell’s paradox and the Liar paradox in that it doesn’t essentially involve the notion of negation. Common truth-theoretic versions involve a sentence that says of itself that if it is true then an arbitrarily chosen claim is true, or—to use a more sinister instance—says of itself that if it is true then every falsity is true. The paradox is that the existence of such a sentence appears to imply the truth of the arbitrarily chosen claim, or—in the more sinister instance—of every falsity. In this entry, we show how the various Curry paradoxes can be constructed, examine the space of available solutions, and explain some ways Curry’s paradox is significant and poses distinctive challenges. (shrink)

For many decades, the proponents of `artificial intelligence' have maintained that computers will soon be able to do everything that a human can do. In his bestselling work of popular science, Sir Roger Penrose takes us on a fascinating roller-coaster ride through the basic principles of physics, cosmology, mathematics, and philosophy to show that human thinking can never be emulated by a machine.

This book is a fascinating and accessible summary of Roger Penrose's current thinking on those areas of physics in which he feels there are major...

Two currently much discussed views about truth, truth pluralism and truth relativism, are found in Sellars’s writings. I show that his motivations for adoping these views are interestingly different from those shared by most of their recent advocates. First, I explain how Sellars comes to embrace a version of truth pluralism. I argue that his version overcomes a difficulty confronting pluralists, albeit at a serious cost. Then I argue that Sellars’s truth pluralism isn’t motivated by his interest in domains of (...) discourse beyond the “matter-of-factual.” Rather, the key to his truth pluralism, his analysis of truth as “semantical assertibility,” is motivated by the same consideration that leads him to adopt truth relativism. This is his interest in applying semantic notions to discourse that embodies conceptual structures other than ours. Despite their common motivation, I conclude that Sellars’s relativism is independent of, and indeed stands in tension with, the analysis of truth that underlies his pluralism. (shrink)

Although general equilibrium theory originated in the late nineteenth century, modern elaboration and development of the theory began only in the 1930s and 1940s. This book focuses on the version of the theory developed in the second half of the twentieth century, referred to by Lionel McKenzie as the classical general equilibrium theory. McKenzie offers detailed and rigorous treatment of the classical model, giving step-by-step proofs of the basic theorems. In many cases he elaborates on the individual steps to (...) give a fuller understanding of the underlying principles. His goal is to provide readers with a true mastery of the methodology so that they can derive new results that will further enrich their thinking about general equilibrium theory. Special attention is given to the McKenzie model, in which it is not assumed that the number of firms is given but rather that technologies or activities are available to any agents who can supply the resources they require. The McKenzie model is used to establish the turnpike theorems of optimal and competitive capital accumulation. (shrink)

Chacun d'entre nous fait partie du monde, certes. Mais, au-delà de son évidence, quelle est la signification d'une telle formule? Comment faisons-nous partie du monde? Comment sommes-nous reliés à tout ce qui n'est pas nous : les autres, le reste de la nature, le cosmos? Lionel Naccache répond à cette énigme intemporelle à partir d'une approche mathématique fondée sur la distinction entre ensembles discrets et ensembles continus : alors qu'un élément, qui fait partie d'un ensemble discret, reste séparé des (...) autres éléments par des frontières tranchées, ces frontières disparaissent dans un ensemble continu. La question devient alors : sommes-nous reliés au reste du monde par des liens continus ou par des liens discrets? Muni de cette boussole, Lionel Naccache nous propose une odyssée passionnante et pleine de gai savoir éclectique qui nous entraîne de la psychologie de la subjectivité vers les sciences du cerveau et de la conscience, les origines et l'évolution des idées mathématiques et la philosophie politique. Au bout du voyage, Lionel Naccache formule une nouvelle éthique pour le XXIe siècle"--Page 4 of cover. (shrink)

Two texts that raise problems for Alexander of Aphrodisias' theory of universals are examined. "De anima" 90.2-8 appears to suggest that universals are dependent on thought for their existence; this raises questions about the status both of universals and of forms. It is suggested that the passage is best interpreted as indicating that universals are dependent on thought only for their being recognised as universals. The last sentence of "Quaestio" 1.11 seems to assert that if the universal did not exist (...) no individual would exist, thereby contradicting Alexander's position elsewhere. This seems to be a slip resulting from the fact that species with only one member are the exception rather than the rule. (shrink)

ABSTRACT:‘Race’ has long searched for a stable, suitable idea, with no consensus on a master meaning in sight. What I call deflationary pluralism about the existence of race recognizes that various meanings may be true as far as they go but avoids murky disputes over whether there are races in some sense. Once we have rejected the notion that racial essences yield innate cognitive differences, there is little point to arguing over the race idea. In its place, I propose the (...) idea of socioancestry, which jettisons racial thinking yet recognizes the social dynamics of color. For example, Black Americans, many of whom have traceable non-African ancestry, constitute an Africa-identified, socioancestrally black subgroup. ‘Race’ talk is not needed to sustain legitimate color-conscious approaches to social identity and social justice. Long-standing fixation on the race idea has obscured the simple truth that visible continental ancestry is the root of the social reality of color consciousness. (shrink)

This book provides a collection of sources, many of them fragmentary and previously scattered and hard to access, for the development of Peripatetic philosophy in the later Hellenistic period and the early Roman Empire. It also supplies the background against which the first commentator on Aristotle from whom extensive material survives, Alexander of Aphrodisias (fl. c. AD 200), developed his interpretations which continue to be influential even today. Many of the passages are here translated into English for the first time, (...) including the whole of the summary of Peripatetic ethics attributed to 'Arius Didymus'. (shrink)

Deflationists about truth seek to undermine debates about the nature of truth by arguing that the truth predicate is merely a device that allows us to express a certain kind of generality. I argue that a parallel approach is available in the case of logical consequence. Just as deflationism about truth offers an alternative to accounts of truth's nature in terms of correspondence or justification, deflationism about consequence promises an alternative to model-theoretic or proof-theoretic accounts of consequence's nature. I then (...) argue, against considerations put forward by Field and Beall, that Curry's paradox no more rules out deflationism about consequence than the liar paradox rules out deflationism about truth. (shrink)

This remarkable history tells the story of the independent city-republic of Basel in the nineteenth century, and of four major thinkers who shaped its intellectual history: the historian Jacob Burckhardt, the philologist and anthropologist Johann Jacob Bachofen, the theologian Franz Overbeck, and the philosopher Friedrich Nietzsche. "Remarkable and exceptionally readable... There is wit, wisdom and an immense erudition on every page."—Jonathan Steinberg, Times Literary Supplement "Gossman's book, a product of many years of active contemplation, is a tour de force. It (...) is at once an intellectual history, a cultural history of Basel and Europe, and an important contribution to the study of nineteenth-century historiography. Written with a grace and elegance that many aspire to, few seldom achieve, this is model scholarship."—John R. Hinde, American Historical Review. (shrink)

The following is an edited version of Roger Penrose's lecture at the Fifth Mind and Brain Symposium at the Institute of Psychiatry, London, on 29 October 1994, introducing the themes of his recent book Shadows of the Mind. The talk begins by outlining some options for the modelling of the relationship between consciousness and computation, and provides evidence for a model in which it is not possible even in principle to simulate mathematical understanding computationally. It is argued that mathematical (...) understanding is on a continuum with consciousness in general, and that non-computability is a feature of all consciousness. The talk then goes on to outline some of the problems of the relationship between quantum and classical physics and proposes a new theory of `objective reduction' by quantum gravity to bridge the explanatory gap. The talk concludes by examining cytoskeletal microtubules as a possible site for quantum-coherent events in the brain. It is suggested that this might be the physical basis of conscious events. (shrink)

First series: exposition -- Second series: media -- Third series: publication -- Fourth series: controversy -- Fifth series: institutions -- Sixth series: archaeology -- Sites of the Conte.