We examine how degrees of computably enumerable equivalence relations under computable reduction break down into isomorphism classes. Two ceers are isomorphic if there is a computable permutation of ω which reduces one to the other. As a method of focusing on nontrivial differences in isomorphism classes, we give special attention to weakly precomplete ceers. For any degree, we consider the number of isomorphism types contained in the degree and the number of isomorphism types of weakly precomplete ceers contained in the (...) degree. We show that the number of isomorphism types must be 1 or ω, and it is 1 if and only if the ceer is self-full and has no computable classes. On the other hand, we show that the number of isomorphism types of weakly precomplete ceers contained in the degree can be any member of $[0,\omega ]$. In fact, for any $n \in [0,\omega ]$, there is a degree d and weakly precomplete ceers ${E_1}, \ldots,{E_n}$ in d so that any ceer R in d is isomorphic to ${E_i} \oplus D$ for some $i \le n$ and D a ceer with domain either finite or ω comprised of finitely many computable classes. Thus, up to a trivial equivalence, the degree d splits into exactly n classes.We conclude by answering some lingering open questions from the literature: Gao and Gerdes [11] define the collection of essentially FC ceers to be those which are reducible to a ceer all of whose classes are finite. They show that the index set of essentially FC ceers is ${\rm{\Pi }}_3^0$-hard, though the definition is ${\rm{\Sigma }}_4^0$. We close the gap by showing that the index set is ${\rm{\Sigma }}_4^0$-complete. They also use index sets to show that there is a ceer all of whose classes are computable, but which is not essentially FC, and they ask for an explicit construction, which we provide.Andrews and Sorbi [4] examined strong minimal covers of downwards-closed sets of degrees of ceers. We show that if $\left$ is a uniform c.e. sequence of non universal ceers, then $\left\{ {{ \oplus _{i \le j}}{E_i}|j \in \omega } \right\}$ has infinitely many incomparable strong minimal covers, which we use to answer some open questions from [4].Lastly, we show that there exists an infinite antichain of weakly precomplete ceers. (shrink)

Descartes claimed that the Cogito is ‘so firm and sure that all the most extravagant suppositions of the sceptics were incapable of shaking it’. This paper aims to demonstrate that this claim is false by presenting a sceptical scenario for the Cogito. It is argued that the story ‘The Circular Ruins’ by J. L. Borges illustrates that one can doubt one’s own existence and that pace Descartes (and many others) the claim ‘I am, I exist, is necessarily true whenever it (...) is put forward by me or conceived in my mind’ is false. (shrink)

In the following pages we propose a theory on cognitive systems and the common strategies of perception, which are at the basis of their function. We demonstrate that these strategies are easily seen to be in place in known cognitive systems such as vision and language. Furthermore we show that taking these strategies into consideration implies a new outlook on immune function calling for a new appraisal of the immune system as a cognitive system.

How far should our realism extend? For many years philosophers of mathematics and philosophers of ethics have worked independently to address the question of how best to understand the entities apparently referred to by mathematical and ethical talk. But the similarities between their endeavours are not often emphasised. This book provides that emphasis. In particular, it focuses on two types of argumentative strategies that have been deployed in both areas. The first—debunking arguments—aims to put pressure on realism by emphasising the (...) seeming redundancy of mathematical or moral entities when it comes to explaining our judgements. In the moral realm this challenge has been made by Gilbert Harman and Sharon Street; in the mathematical realm it is known as the 'Benacerraf-Field' problem. The second strategy—indispensability arguments—aims to provide support for realism by emphasising the seeming intellectual indispensability of mathematical or moral entities, for example when constructing good explanatory theories. This strategy is associated with Quine and Putnam in mathematics and with Nicholas Sturgeon and David Enoch in ethics. Explanation in Ethics and Mathematics addresses these issues through an explicitly comparative methodology which we call the 'companions in illumination' approach. By considering how argumentative strategies in the philosophy of mathematics might apply to the philosophy of ethics, and vice versa, the papers collected here break new ground in both areas. For good measure, two further companions for illumination are also broached: the philosophy of chance and the philosophy of religion. Collectively, these comparisons light up new questions, arguments, and problems of interest to scholars interested in realism in any area. (shrink)

We show that the theory of the partial order of computably enumerable equivalence relations (ceers) under computable reduction is 1-equivalent to true arithmetic. We show the same result for the structure comprised of the dark ceers and the structure comprised of the light ceers. We also show the same for the structure of L-degrees in the dark, light, or complete structure. In each case, we show that there is an interpretable copy of (N, +, \times) .

Assuming the existence of a supercompact cardinal and a weakly compact cardinal above it, we provide a generic extension where there are no Aronszajn trees of height ω 2 or ω 3 . On the other hand we show that some large cardinal assumptions are necessary for such a consistency result.

We discuss the problem of finding forcing posets which introduce closed unbounded subsets to a given stationary set.

Commentators provide two different accounts of desires in Kant: “feeling-based” accounts stress their connection with feelings, while “action-based” accounts view them as causes of action. I argue that “feeling-based” accounts blur the feeling-desire distinction, while the “action-based” accounts conflict with Kantian desires that do not cause action. On my alternative, Kantian desires are dispositions to action normally directed at producing future objects, and so they differ from the feelings they are connected to, which refer to the way we are affected (...) by objects. This account preserves the feeling-desire distinction, is compatible with desires that do not cause action, and anticipates holistic theories of desire that combine dispositional, hedonic, and evaluative components. (shrink)

The current study aims to examine how the intense emotions experienced by different Israeli groups during the 2006 Second Lebanon War affected their perceptions of risk. Two weeks after the end of the war, a questionnaire was distributed among 205 people. Some were from the north and had been directly affected by the rocket attacks; others were from the center of Israel. The questionnaires, based on Lerner et al., measured emotions and perceived risk. The results show significant differences between those (...) living in the north and those in the center of Israel. As expected, people living in the north reported more emotional difficulties during the war, greater perceived risk, and more pessimism in comparison to the center group. Moreover, the results point to significant differences between Israeli Jews and Israeli Arabs regarding emotions and perceived risk. In addition, the study results show a positive relation between anger and perceived risk. (shrink)

We present a theoretical model and corresponding research design (Bronfenbrenner & Ceci 1994) that could yield stronger evidence for (or perhaps against) Howe et al.'s conclusions. The model assesses levels of heritability (h²) under different amounts of training and practice, thus providing estimates of the independent contribution of “innate talent” to the quality of development outcomes. The design can also reveal the extent to which this independent contribution varies systematically as a function of other influential factors identified by Howe et (...) al. (shrink)

This study investigates the ontological status of some physical and cosmological theories that are not based on empirical observation and probably cannot be tested empirically. It is suggested that these theories exist only in our consciousness and are no more than Kantian ideas. Indeed, these theories imply paradoxes as was predicted by Kant regarding ideas of pure reason.

Name der Zeitschrift: Naharaim Jahrgang: 8 Heft: 2 Seiten: 210-226.

A forcing poset of size 221 which adds no new reals is described and shown to provide a Δ22 definable well-order of the reals . The encoding of this well-order is obtained by playing with products of Aronszajn trees: some products are special while other are Suslin trees. The paper also deals with the Magidor–Malitz logic: it is consistent that this logic is highly noncompact.

Monists, pluralists, and particularists disagree about the structure of the best explanation of the rightness (wrongness) of actions. In this paper I argue that the availability of good moral advice gives us reason to prefer particularist theories and pluralist theories to monist theories. First, I identify two distinct roles of moral theorizing—explaining the rightness (wrongness) of actions, and providing moral advice—and I explain how these two roles are related. Next, I explain what monists, pluralists, and particularists disagree about. Finally, I (...) argue that particularists and pluralists are better situated than monists to explain why it is a good idea to think before we act, and that this gives us reason to favor particularism and pluralism over monism. (shrink)

What makes some acts morally right and others morally wrong? Traditionally, philosophers have thought that in order to answer this question we must find and formulate exceptionless moral principles—principles that capture all and only morally right actions. Utilitarianism and Kantianism are paradigmatic examples of such attempts. In recent years, however, there has been a growing interest in a novel approach—Particularism—although its precise content is still a matter of controversy. In this paper I develop and motivate a new formulation of particularism (...) as a research program and I show that my formulation is not vulnerable to the most common objections to particularism. Moreover, I argue that the particularist research program shows enough promise to warrant further exploration. (shrink)

It is known that every non-universal self-full degree in the structure of the degrees of computably enumerable equivalence relations (ceers) under computable reducibility has exactly one strong minimal cover. This leaves little room for embedding wide partial orders as initial segments using self-full degrees. We show that considerably more can be done by staying entirely inside the collection of non-self-full degrees. We show that the poset can be embedded as an initial segment of the degrees of ceers with infinitely many (...) classes. A further refinement of the proof shows that one can also embed the free distributive lattice generated by the lower semilattice as an initial segment of the degrees of ceers with infinitely many classes. (shrink)

The lambda model of Feldman & Levin for intentional hand movement is compared with a hemispheric motor model (IIMM). Both models imply similar conclusions independently. This increases the validity of both models.

Until recent times, the collection of Salomon Maimons early works written in Hebrew, Hesheq Shelomo, was not included into the scientific circulation. An article of professor Gideon Freudenthal on the formation of the young Maimon, filled this lacuna, proving the importance of the analysis of philosophers early works for the comprehension of his literary heritage in general. Freudenthal had studied and published Maimons introduction to Hesheq Shelomo, and then one of the collections treatises, Maаse Livnat ha-Sаppir, consecrated to the ideas (...) and notions of kabbalah. In his analysis Freudenthal had focused on Maimons rational interpretation of kabbalah. The present article represents an attempt to expand Freudenthals research, adding an analysis of another aspect of young Maimons thought. We will try to show that kabbalah, generally understood by early Maimon as ancient Jewish knowledge, had, according to the thinker, to complete philosophy and mitigate arising in it problems. In his early works Maimon was not only criticizing widely occurring profane kabbalah, but also Maimonides philosophy. According to Maimon, it is not possible to understand the true kabbalah without philosophy, but philosophical knowledge is not complete and often erroneous without kabbalah: the true kabbalah rectifies and adjusts it. The critic of Aristotelianism and its derivate, proposed by Maimon in his early works, can add clarity to the understanding of the development of his philosophical thought in the late period. (shrink)

"Nietzsche Trauma and Overcoming " shows that Nietzsche suffered from Post-Traumatic Stress Disorder, and most probably was a victim of childhood sex abuse. I bring convincing evidence from his texts to support these claims, along with a discussion of corroborating psychological findings on these issues. I show that he teaches coping with pain and suffering, based on his life experience, with lessons from the school of war, the wisdom of reinterpretation, and artistic activity. His three themes of the Superman, Eternal (...) Recurrence, and the Will to Power, the heart of his philosophy and psychology, are understood in a new light, in relation to his personal suffering and overcoming. The book criticizes the attempts to diagnose Nietzsche as suffering from various psychiatric disorders, psychoanalyze him as a fatherless child grown old, and outing him as a closet homosexual. These approaches lead to a dead-end. Firstly, it is impossible to prove that someone is a paragon of mental health, not a covert homosexual, and unmoved by a parent’s death. Secondly, these speculations explain only a small part of Nietzsche’s personal statements, found in his writings. Thirdly, and most importantly, they do not change our understanding of his ideas and how they were arrived at; they do not increase our appreciation of him; and do not leave us with any lessons for life (the goal of any good writing according to Nietzsche). (shrink)

This article describes the tripartite structure, a formative style used in the redaction of some sugyot in Tractate Eruvin. The attitude to the tripartite structure is portrayed here as reflected by commentators and researchers who mentioned this pattern, whether directly or indirectly. The purpose of the article is to present several select examples of the tripartite structure in some sugyot in Tractate Eruvin. This will have the significant effect of illuminating different literary forms worthy of exploration, such as the tripartite (...) structure here, as well as in other Talmudic sugyot whose focus is mainly halakhic. Sometimes the form utilized has a considerable effect on redaction of the contents, for example for understanding the sugya or solving various difficulties that it contains. These patterns are also evident in other additional sugyot and they constitute an important research foundation for examining their application in additional sugyot in the different tractates. (shrink)

Moral philosophers are, among other things, in the business of constructing moral theories. And moral theories are, among other things, supposed to explain moral phenomena. Consequently, one’s views about the nature of moral explanation will influence the kinds of moral theories one is willing to countenance. Many moral philosophers are (explicitly or implicitly) committed to a deductive model of explanation. As I see it, this commitment lies at the heart of the current debate between moral particularists and moral generalists. In (...) this paper I argue that we have good reasons to give up this commitment. In fact, I show that an examination of the literature on scientific explanation reveals that we are used to, and comfortable with, non-deductive explanations in almost all areas of inquiry. As a result, I argue that we have reason to believe that moral explanations need not be grounded in exceptionless moral principles. (shrink)

We investigate the form of mathematical structuralism that acknowledges the existence of structures and their distinctive structural elements. This form of structuralism has been subject to criticisms recently, and our view is that the problems raised are resolved by proper, mathematics-free theoretical foundations. Starting with an axiomatic theory of abstract objects, we identify a mathematical structure as an abstract object encoding the truths of a mathematical theory. From such foundations, we derive consequences that address the main questions and issues that (...) have arisen. Namely, elements of different structures are different. A structure and its elements ontologically depend on each other. There are no haecceities and each element of a structure must be discernible within the theory. These consequences are not developed piecemeal but rather follow from our definitions of basic structuralist concepts. (shrink)

Descartes claimed that the Cogito is ‘so firm and sure that all the most extravagant suppositions of the sceptics were incapable of shaking it’. This paper aims to demonstrate that this claim is false by presenting a sceptical scenario for the Cogito. It is argued that the story ‘The Circular Ruins’ by J. L. Borges illustrates that one can doubt one’s own existence and that pace Descartes (and many others) the claim ‘I am, I exist, is necessarily true whenever it (...) is put forward by me or conceived in my mind’ is false. (shrink)

This article deals with a tripartite structure applied to a Tannaitic source. This structure is designed in the form of a difficulty and a short resolution, bringing one example for each of the three parts of the Tannaitic source. The uniform formative-stylistic phrasing gives the discussion of the Tannaitic source's three parts a tripartite form. The Tannaitic source utilises a chaining of examples from the first to the second part and from the second to the third part.

The paper identifies a distinctive feature of friendship. Friendship, it is argued, is a relationship between two people in which each participant values the other and successfully communicates this fact to the other. This feature of friendship, it is claimed, explains why friendship plays a key role in human happiness, why it is praised by philosophers, poets, and novelists, and why we all seek friends. Although the characterization of friendship proposed here differs from other views in the literature, it is (...) shown that it accommodates key insights of other writers on the topic. Thus, in accordance with the Aristotelian strategy the paper employs, it is shown that the account on offer preserves the received opinions on friendship. (shrink)

We address the following questions in this paper: (1) Which set or number existence axioms are needed to prove the theorems of ‘ordinary’ mathematics? (2) How should Frege’s theory of numbers be adapted so that it works in a modal setting, so that the fact that equivalence classes of equinumerous properties vary from world to world won’t give rise to different numbers at different worlds? (3) Can one reconstruct Frege’s theory of numbers in a non-modal setting without mathematical primitives such (...) as “the number of Fs” ( $$\#F$$ ) or mathematical axioms such as Hume’s Principle? Our answer to question (1) is ‘None’. Our answer to question (2) begins by defining ‘x numbers G’ as: x encodes all and only the properties F such that being-actually-F is equinumerous to G with respect to discernible objects. We answer (3) by showing that the mere existence of discernible objects allows one to reconstruct Frege’s derivation of the Dedekind-Peano axioms in a non-modal setting. (shrink)

Commentators disagree about Kant’s view on the proper treatment of emotions. In contrast to a tendency in this literature to treat them uniformly, I argue that, according to Kant, feelings (but not affects) require cultivation, and inclinations – although they can and perhaps may be cultivated – generally require discipline. The appropriate treatment for emotions depends on their susceptibility to rational constraint and on the threat they pose to rational deliberation. Although I read Kant as recommending that we cultivate certain (...) emotions, I argue that my reading is not vulnerable to Thomason’s recent pertinent objections to such readings. (shrink)

We present two experiments that cast doubt on existing evidence suggesting that it is impossible to suspend belief in a comprehended proposition. In Experiment 1, we found that interrupting the encoding of a statement's veracity decreased memory for the statement's falsity when the false version of the statement was uninformative, but not when the false version was informative. This suggests that statements that are informative when false are not represented as if they were true. In Experiment 2, participants made faster (...) lexical decisions to words implied by preceding statements when they were told that the statements were true than when the veracity of the statements was unknown or when the statements were false. The findings suggest that comprehending a statement may not require believing it, and that it may be possible to suspend belief in comprehended propositions. (shrink)

Any model of ZFC + GCH has a generic extension (made with a poset of size ℵ 2 ) in which the following hold: MA + 2 ℵ 0 = ℵ 2 +there exists a Δ 2 1 -well ordering of the reals. The proof consists in iterating posets designed to change at will the guessing properties of ladder systems on ω 1 . Therefore, the study of such ladders is a main concern of this article.

In this essay I offer a new particularist reading of Aristotle’s Nicomachean Ethics. I argue that the interpretation I present not only helps us to resolve some puzzles about Aristotle’s goals and methods, but it also gives rise to a novel account of morality—an account that is both interesting and plausible in its own right. The goal of this paper is, in part, exegetical—that is, to figure out how to best understand the text of the Nicomachean Ethics. But this paper (...) also aims to contribute to the current exciting and controversial debate over particularism. By taking the first steps towards a comprehensive particularist reading of Aristotle’s Ethics I hope to demonstrate that some of the mistrust of particularism is misplaces and that what is, perhaps, the most influential moral theory in the history of philosophy is, arguably, a particularist moral theory. (shrink)

Many of us read Peter Singer ’ s work on our obligations to those in desperate need with our students. Famously, Singer argues that we have a moral obligation to give a significant portion of our assets to famine relief. If my own experience is not atypical, it is quite common for students, upon grasping the implications of Singer ’ s argument, to ask whether Singer gives to famine relief. In response it might be tempting to remind students of the (...) ad hominem fallacy of attacking the person advancing an argument rather than the argument itself. In this paper I argue that the “ ad hominem reply ” to students ’ request for information about Singer is misguided. First I show that biographical facts about the person advancing an argument can constitute indirect evidence for the soundness / unsoundness of the argument. Second, I argue that such facts are relevant because they may reveal that one can discard the argument without thereby incurring moral responsibility for failing to act on its conclusion even if the argument is sound. (shrink)

According to Alix Cohen, Kant defines emotions as ‘feelings’. Although I find her account of Kantian feelings compelling, I provide three reasons to doubt that it is an account of emotions: (1) it is unclear why Cohen identifies emotions with Kantian feelings; (2) some Kantian feelings are not emotions; (3) some Kantian desires may be emotions. I propose, however, that with some qualifications Cohen’s account may be upheld, provided its extra-textual assumptions about emotions are explicated. Against her claim that Kantian (...) feelings have a derived intentionality, I argue that the text is compatible with their being intrinsically intentional. (shrink)