Euclidean geometry, as presented by Euclid, consists of straightedge-and-compass constructions and rigorous reasoning about the results of those constructions. We show that Euclidean geometry can be developed using only intuitionistic logic. This involves finding “uniform” constructions where normally a case distinction is used. For example, in finding a perpendicular to line L through point p, one usually uses two different constructions, “erecting” a perpendicular when p is on L, and “dropping” a perpendicular when p is not on L, but in (...) constructive geometry, it must be done without a case distinction. Classically, the models of Euclidean geometry are planes over Euclidean fields. We prove a similar theorem for constructive Euclidean geometry, by showing how to define addition and multiplication without a case distinction about the sign of the arguments. With intuitionistic logic, there are two possible definitions of Euclidean fields, which turn out to correspond to different versions of the parallel postulate.We consider three versions of Euclid’s parallel postulate. The two most important are Euclid’s own formulation in his Postulate 5, which says that under certain conditions two lines meet, and Playfair’s axiom, which says there cannot be two distinct parallels to line L through the same point p. These differ in that Euclid 5 makes an existence assertion, while Playfair’s axiom does not. The third variant, which we call the strong parallel postulate, isolates the existence assertion from the geometry: it amounts to Playfair’s axiom plus the principle that two distinct lines that are not parallel do intersect. The first main result of this paper is that Euclid 5 suffices to define coordinates, addition, multiplication, and square roots geometrically.We completely settle the questions about implications between the three versions of the parallel postulate. The strong parallel postulate easily implies Euclid 5, and Euclid 5 also implies the strong parallel postulate, as a corollary of coordinatization and definability of arithmetic. We show that Playfair does not imply Euclid 5, and we also give some other independence results. Our independence proofs are given without discussing the exact choice of the other axioms of geometry; all we need is that one can interpret the geometric axioms in Euclidean field theory. The independence proofs use Kripke models of Euclidean field theories based on carefully constructed rings of real-valued functions. “Field elements” in these models are real-valued functions. (shrink)

This article answers two questions (posed in the literature), each concerning the guaranteed existence of proofs free of double negation. A proof is free of double negation if none of its deduced steps contains a term of the formn(n(t)) for some term t, where n denotes negation. The first question asks for conditions on the hypotheses that, if satisfied, guarantee the existence of a double-negation-free proof when the conclusion is free of double negation. The second question asks about the existence (...) of an axiom system for classical propositional calculus whose use, for theorems with a conclusion free of double negation, guarantees the existence of a double-negation-free proof. After giving conditions that answer the first question, we answer the second question by focusing on the Lukasiewicz three-axiom system. We then extend our studies to infinite-valued sentential calculus and to intuitionistic logic and generalize the notion of being double-negation free. The double-negation proofs of interest rely exclusively on the inference rule condensed detachment, a rule that combines modus ponens with an appropriately general rule of substitution. The automated reasoning program Otter played an indispensable role in this study. (shrink)

We use Herbrand’s theorem to give a new proof that Euclid’s parallel axiom is not derivable from the other axioms of first-order Euclidean geometry. Previous proofs involve constructing models of non-Euclidean geometry. This proof uses a very old and basic theorem of logic together with some simple properties of ruler-and-compass constructions to give a short, simple, and intuitively appealing proof.

The pain -- I thought church would be different -- The pain goes so deep -- Where does all this pain come from? -- Nobody sees me -- I feel beat up in church -- I live in shame all the time -- I feel used -- I can't forgive -- The hope -- Will I ever get past the pain? -- Why do I feel so unsafe in church? -- I can't keep up with all the rules -- What's (...) wrong with these people? -- I just need to be perfect -- The church doesn't seem to care -- How do I find a good church? -- Hope beyond the pain -- Demonic lies and doctrines -- Learning to live in the kingdom of light. (shrink)

In this multiple case study, the authors compare the instruction of two high school civics teachers during the 2012 Presidential Election. Both were highly-qualified practitioners who worked in schools with one-to-one laptop initiatives, creating an environment in which access to digital technology ceased to be an issue. Although both teachers regularly used technology in their classrooms, the authors describe stark differences in the complexity and authenticity of their instruction, which the authors attribute to the teachers’ technological pedagogical content knowledge (TPCK). (...) The authors conclude by discussing implications for better understanding TPCK within civics instruction, specifically in classrooms with one-to-one laptop access. (shrink)

This book defends a form of ethical intuitionism, according to which (i) there are objective moral truths; (ii) we know some of these truths through a kind of immediate, intellectual awareness, or "intuition"; and (iii) our knowledge of moral truths gives us reasons for action independent of our desires. The author rebuts all the major objections to this theory and shows that the alternative theories about the nature of ethics all face grave difficulties.

The first edition of The Scientific Background to Modern Philosophy took the dialogue of science and philosophy from Aristotle through to Newton. This second edition adds eight chapters, taking the dialogue through the Enlightenment and up to Darwin. This anthology is an attempt to help bridge the gap between the history of science and the history of philosophy.

Part I: The representation of life -- Can life be given a real definition? -- The representation of the living individual -- The representation of the life-form itself -- Part II: Naive action theory -- Types of practical explanation -- Naive explanation of action -- Action and time -- Part III: Practical generality -- Two tendencies in practical philosophy -- Practices and dispositions as sources of the goodness of individual actions -- Practice and disposition as sources of individual action.

Virtually all philosophers agree that for a belief to be epistemically justified, it must satisfy certain conditions. Perhaps it must be supported by evidence. Or perhaps it must be reliably formed. Or perhaps there are some other "good-making" features it must have. But does a belief's justification also require some sort of awareness of its good-making features? The answer to this question has been hotly contested in contemporary epistemology, creating a deep divide among its practitioners. Internalists, who tend to focus (...) on scientific or theoretical beliefs as the ideal, insist that such awareness is required for justification. Externalists, who think children's ordinary beliefs in obvious facts are paradigm cases of justified belief, say it isn't required. Michael Bergmann's book offers a decisive refutation of internalism and a sustained defense of externalism. (shrink)

Externalist theories of justification create the possibility of cases in which everything appears to one relevantly similar with respect to two propositions, yet one proposition is justified while the other is not. Internalists find this difficult to accept, because it seems irrational in such a case to affirm one proposition and not the other. The underlying internalist intuition supports a specific internalist theory, Phenomenal Conservatism, on which epistemic justification is conferred by appearances.

At the University of Sheffield during 2011 and 2012, a leading group of philosophers, psychologists, and others gathered to explore the nature and significance of implicit bias. The two volumes of Implicit Bias and Philosophy emerge from these workshops. Each volume philosophically examines core areas of psychological research on implicit bias as well as the ramifications of implicit bias for core areas of philosophy. Volume I: Metaphysics and Epistemology is comprised of two parts: “The Nature of Implicit Attitudes, Implicit Bias, (...) and Stereotype Threat,” and “Skepticism, Social Knowledge, and Rationality.” The first part contains chapters examining the relationship between implicit attitudes and “dual process” models of the mind; the role of affect in the formation and change of implicit associations; the unity (or disunity) of implicit attitudes; whether implicit biases are mental states at all; and whether performances on stereotype-relevant tasks are automatic and unconscious or intentional and strategic. The second part contains chapters examining implicit bias and skepticism; the effects of implicit bias on scientific research; the accessibility of social stereotypes in epistemic environments; the effects of implicit bias on the self-perception of members of stigmatized social groups as rational agents; the role of gender stereotypes in philosophy; and the role of heuristics in biased reasoning. (shrink)

Causation: A Realist Approach Traditional empiricist accounts of causation and laws of nature have been reductionist in the sense of entailing that given a complete specification of the non-causal properties of and relations among particulars, it is therefore logically determined both what laws there are and what events are causally related. It is argued here, however, that reductionist accounts of causation and of laws of nature are exposed to decisive objections, and thus that the time has come for empiricists to (...) break with that tradition. -/- The basic goal of this book, therefore, is to set out and defend realistic accounts of those concepts. In the case of causal relations, for example, Tooley maintains that causation is basically a matter of theoretical relations between states of affairs that underlie and explain relative frequencies. He also argues that such an approach avoids the objections that tell against reductionist accounts and that it does so without making causal relations epistemologically inaccessible. (shrink)

In this engaging and spirited text, Michael Lynch argues that truth does matter, in both our personal and political lives. He explains that the growing cynicism over truth stems in large part from our confusion over what truth is.

Dignity plays a central role in current thinking about law and human rights, but there is sharp disagreement about its meaning. Combining conceptual precision with a broad historical background, Michael Rosen puts these controversies in context and offers a novel, constructive proposal. “Penetrating and sprightly...Rosen rightly emphasizes the centrality of Catholicism in the modern history of human dignity. His command of the history is impressive...Rosen is a wonderful guide to the recent German constitutional thinking about human dignity...[Rosen] is in (...) general an urbane and witty companion, achieving his aim of accessibly written philosophy.” —Samuel Moyn, The Nation “[An] elegant, interesting and lucid exploration of the concept of dignity...Drawing on classical, liberal and Catholic traditions, Rosen hopes to rehabilitate dignity to its rightful place near the centre of moral thought...Rosen's admirable book deserves wide attention from political theorists, jurisprudes and political philosophers.” —Simon Blackburn, Times Higher Education “Dignity deserves to be widely read, not only for its intrinsic interest, but also as a corrective to the habit of discussing such topics in abstraction from their social context. Whether or not one agrees with Rosen's arguments, there can be no doubt he has widened our horizons.” —Rae Langton, Times Literary Supplement. (shrink)

edition (unseen), $12.95. traditions, bringing into being new modes of understanding. Paper Anthropology, and particularly ethnography, is torn between two quests, one to capture the diversity of social life and the other to discover universal principles structuring that diversity. Jackson examines these quests within the context of ethnographic fieldwork, focusing on the relationship between ethnographers and the people they study. He is concerned with defining the anthropological project as something more than the projection of the anthropologist's traditions and concerns onto (...) an alien culture. Rather, he would have the project open a genuine dialogue between people from different cultures or Annotation copyrighted by Book News, Inc., Portland, OR. (shrink)

Michael G. Titelbaum presents a new Bayesian framework for modeling rational degrees of belief—the first of its kind to represent rational requirements on agents who undergo certainty loss.

Under the assumption that all "rules" are recursive (ECT) the statement $\operatorname{Cont}(N^N,N)$ that all functions from N N to N are continuous becomes equivalent to a statement KLS in the language of arithmetic about "effective operations". Our main result is that KLS is underivable in intuitionistic Zermelo-Fraenkel set theory + ECT. Similar results apply for functions from R to R and from 2 N to N. Such results were known for weaker theories, e.g. HA and HAS. We extend not only (...) the theorem but the method, fp-realizability, to intuitionistic ZF. (shrink)

In this paper, I propose a new way of defining sport that I call a ‘core-periphery’ model. According to a core-periphery model, sport comes in degrees – what I refer to as ‘sport-likeness’ – and the aim of the philosopher of sport is to chart those dimensions along which an activity can be more or less a sport. By introducing the concept of sport-likeness, the core-periphery model complicates the picture of what is or is not a sport and encourages philosophers (...) interested in defining sport to engage with the social sciences in exploring the extension of the term sport in common usage. In this paper I present the results of a small survey about attitudes to sport, and use it to illustrate how a core-periphery definition of sport would proceed. (shrink)

While philosophers hold that it is patently absurd to blame robots or hold them morally responsible [1], a series of recent empirical studies suggest that people do ascribe blame to AI systems and robots in certain contexts [2]. This is disconcerting: Blame might be shifted from the owners, users or designers of AI systems to the systems themselves, leading to the diminished accountability of the responsible human agents [3]. In this paper, we explore one of the potential underlying reasons for (...) robot blame, namely the folk's willingness to ascribe inculpating mental states or "mens rea" to robots. In a vignette-based experiment (N=513), we presented participants with a situation in which an agent knowingly runs the risk of bringing about substantial harm. We manipulated agent type (human v. group agent v. AI-driven robot) and outcome (neutral v. bad), and measured both moral judgment (wrongness of the action and blameworthiness of the agent) and mental states attributed to the agent (recklessness and the desire to inflict harm). We found that (i) judgments of wrongness and blame were relatively similar across agent types, possibly because (ii) attributions of mental states were, as suspected, similar across agent types. This raised the question - also explored in the experiment - whether people attribute knowledge and desire to robots in a merely metaphorical way (e.g., the robot "knew" rather than really knew). However, (iii), according to our data people were unwilling to downgrade to mens rea in a merely metaphorical sense when given the chance. Finally, (iv), we report a surprising and novel finding, which we call the inverse outcome effect on robot blame: People were less willing to blame artificial agents for bad outcomes than for neutral outcomes. This suggests that they are implicitly aware of the dangers of overattributing blame to robots when harm comes to pass, such as inappropriately letting the responsible human agent off the moral hook. (shrink)

In previous work I have argued against internalism by means of a dilemma intended to force all internalists to accept one of two undesirable options: either their internalism is unmotivated or it is saddled with vicious regress problems. Recently it has been argued that Phenomenal Conservatism—a theory of justification according to which justification depends on seemings—is a kind of internalism that can escape this dilemma. In this paper, I argue that Phenomenal Conservatism cannot escape my dilemma for internalism. In order (...) to do this, it is helpful to get clear on what Phenomenal Conservatism is saying, and for that reason I begin, in section I, by examining in some detail what seemings are. I then argue, in the remainder of the paper, that, whichever horn of the dilemma for internalism they take, Phenomenal Conservatives are in trouble. (shrink)

This volume presents a selection of the most influential recent discussions of the crucial metaphysical questions: what is it for one event to cause another? The subject of causation bears on many topics, such as time, explanation, mental states, the laws of nature, and the philosphy of science.

Can an ugly experiment be a good experiment? Philosophers have identified many beautiful experiments and explored ways in which their beauty might be connected to their epistemic value. In contrast, the present chapter seeks out (and celebrates) ugly experiments. Among the ugliest are those being designed by AI algorithms. Interestingly, in the contexts where such experiments tend to be deployed, low aesthetic value correlates with high epistemic value. In other words, ugly experiments can be good. Given this, we should conclude (...) that beauty is not generally necessary or sufficient for epistemic value, and increasing beauty will not generally tend to increase epistemic value. (shrink)

Radical skepticism endorses the extreme claim that large swaths of our ordinary beliefs, such as those produced by perception or memory, are irrational. The best arguments for such skepticism are, in their essentials, as familiar as a popular science fiction movie and yet even seasoned epistemologists continue to find them strangely seductive. Moreover, although most contemporary philosophers dismiss radical skepticism, they cannot agree on how best to respond to the challenge it presents. In the tradition of the 18th century Scottish (...) philosopher, Thomas Reid, Radical Skepticism and Epistemic Intuition joins this discussion by taking up four main tasks. First, it identifies the strongest arguments for radical skepticism, namely, underdetermination arguments, which emphasize the gap between our evidence and our ordinary beliefs based on that evidence. Second, it rejects all inferential or argument-based responses to radical skepticism, which aim to lay out good noncircular reasoning from the evidence on which we base our ordinary beliefs to the conclusion that those beliefs are probably true. Third, it develops a commonsense noninferential response to radical skepticism with two distinctive features: it consciously and extensively relies on epistemic intuitions, which are seemings about epistemic goods, such as knowledge and rationality, and it can be endorsed without difficulty by both internalists and externalists in epistemology. Fourth, and finally, it defends this commonsense epistemic-intuition-based response to radical skepticism against a variety of objections, including those connected with underdetermination worries, epistemic circularity, disagreement problems, experimental philosophy, and concerns about whether it engages skepticism in a sufficiently serious way. (shrink)