Modest pessimism about philosophical progress is the view that while philosophy may sometimes make some progress, philosophy has made, and can be expected to make, only very little progress (where the extent of philosophical progress is typically judged against progress in the hard sciences). The paper argues against recent attempts to defend this view on the basis of the pervasiveness of disagreement within philosophy. The argument from disagreement for modest pessimism assumes a teleological conception of progress, according to which the (...) attainment of true answers to the big philosophical questions, or knowledge of them, is the primary goal of philosophy. The paper argues that this assumption involves a misconception of the goal of philosophy: if philosophy has a primary goal, its goal is the understanding of philosophical problems rather than knowledge of answers to philosophical questions. Moreover, it is argued that if the primary goal of philosophy is such understanding, then widespread disagreement within philosophy does not indicate that philosophy makes little progress. (shrink)

According to doxastic accounts of trust, trusting a person to \(\varPhi \) involves, among other things, holding a belief about the trusted person: either the belief that the trusted person is trustworthy or the belief that she actually will \(\varPhi \) . In recent years, several philosophers have argued against doxastic accounts of trust. They have claimed that the phenomenology of trust suggests that rather than such a belief, trust involves some kind of non-doxastic mental attitude towards the trusted person, (...) or a non-doxastic disposition to rely upon her. This paper offers a new account of reasons for trust and employs the account to defend a doxastic account of trust. The paper argues that reasons for trust are preemptive reasons for action or belief. Thus the Razian concept of preemptive reasons, which arguably plays a key role in our understanding of relations of authority, is also central to our understanding of relations of trust. Furthermore, the paper argues that acceptance of a preemptive account of reasons for trust supports the adoption of a doxastic account of trust, for acceptance of such an account both neutralizes central objections to doxastic accounts of trust and provides independent reasons supporting a doxastic account. (shrink)

The paper discusses Linda Zagzebski's account of epistemic authority. Building on Joseph Raz's account of political authority, Zagzebski argues that the basic contours of epistemic authority match those Raz ascribes to political authority. This, it is argued, is a mistake. Zagzebski is correct in identifying the pre-emptive nature of reasons provided by an authority as central to our understanding of epistemic authority. However, Zagzebski ignores important differences between practical and epistemic authority. As a result, her attempt to explain the rationality (...) of belief on authority by applying an analogue of Raz's Normal Justification Thesis to the domain of belief fails. A successful explanation of the rationality of belief on authority will need to be attuned to the differences between political and epistemic authorities. (shrink)

On many science-related policy questions, the public is unable to make informed decisions, because of its inability to make use of knowledge obtained by scientists. Philip Kitcher and James Fishkin have both suggested therefore that on certain science-related issues, public policy should not be decided on by actual democratic vote, but should instead conform to the public’s counterfactual informed democratic decision. Indeed, this suggestion underlies Kitcher’s specification of an ideal of a well-ordered science. This article argues that this suggestion misconstrues (...) the normative significance of CIDDs. At most, CIDDs might have epistemic significance, but no authority or legitimizing force. (shrink)

What should the goals of scientific inquiry be? What questions should scientists investigate, and how should our resources be distributed between different lines of investigation? Philip Kitcher has suggested that we should answer these questions by appealing to an ideal based on the consideration of hypothetical democratic deliberations under ideal circumstances. The paper argues that we have no reason to adopt this ideal. The paper examines both traditional arguments for democracy and Kitcher's own reasons for adopting this ideal, as presented (...) in Kitcher (2001) and in Kitcher (2011b), and argues that none of these supports adoption of Kitcher's proposed ideal. (shrink)

To a large extent, the evidential base of claims in the philosophy of science has switched from thought experiments to case studies. We argue that abandoning thought experiments was a wrong turn, since they can effectively complement case studies. We make our argument via an analogy with the relationship between experiments and observations within science. Just as experiments and ‘natural’ observations can together evidence claims in science, each mitigating the downsides of the other, so too can thought experiments and case (...) studies be mutually supporting. After presenting the main argument, we look at potential concerns about thought experiments, suggesting that a judiciously applied mixed-methods approach can overcome them. (shrink)

Science and fiction seem to lie at opposite ends of the cognitive-epistemic spectrum. The former is typically seen as the study of hard, real-world facts in a rigorous manner. The latter is treated as an instrument of play and recreation, dealing in figments of the imagination. Initial appearances notwithstanding, several central features of scientific modeling in fact suggest a close connection with the imagination and recent philosophers have developed detailed accounts of models that treat them, in one way or another, (...) as akin to fictions. This chapter will critically discuss the fictions approach as an epistemology of scientific modeling. (shrink)

Thought experiments play a role in science and in some central parts of contemporary philosophy. They used to play a larger role in philosophy of science, but have been largely abandoned as part of the field’s “practice turn”. This chapter discusses possible roles for thought experimentation within a practice-oriented philosophy of science. Some of these roles are uncontroversial, such as exemplification and aiding discovery. A more controversial role is the reliance on thought experiments to justify philosophical claims. It is proposed (...) that if we adopt an underlying empiricist view of concepts, then thought experiments can be seen as affording us contact with scientific practice, despite their seemingly a priori character. The advantages and drawbacks of thought experiments are discussed via comparison with case studies, on the one, and simulations on the other hand. The chapter closes with some remarks on how to combine thought experiments with other methods. (shrink)

We argue that the aesthetic domain falls inside the scope of rationality, but does so in its own way. Aesthetic judgment is a stance neither on whether a proposition is to be believed nor on whether an action is to be done, but on whether an object is to be appreciated. Aesthetic judgment is simply appreciation. Correlatively, reasons supporting theoretical, practical and aesthetic judgments operate in fundamentally different ways. The irreducibility of the aesthetic domain is due to the fact that (...) aesthetic judgment is a sensory-affective disclosure of, and responsiveness to, merit: it is a feeling that presents an object, and is responsive to it, as worthy of being liked. Aesthetic judgment is thus shown to be, on the hand, first personal and non-transferable; and, on the other hand, a presentation of reality. We thereby capture what is right in both subjectivist and objectivist conceptions of aesthetic judgment. (shrink)

The aim of the paper is to reassess the prospects of a widely neglected affective conception of the aesthetic evaluation and appreciation of art. On the proposed picture, the aesthetic evaluation and appreciation of art are non-contingently constituted by a particular kind of pleasure. Artworks that are valuable qua artworks merit, deserve, and call for a certain pleasure, the same pleasure that reveals (or at least purports to reveal) them to be valuable in the way that they are, and constitutes (...) their aesthetic evaluation and appreciation. This is why and how art is non-contingently related to pleasure. Call this, the Affective View. While I don’t advance conclusive arguments for the Affective View in this paper, I aim to reassess its prospects by (1) undermining central objections against it, (2) dissociating it from hedonism about the value of artworks (the view that this value is grounded in, and explained by, its possessors’ power to please), and (3) introducing some observations on the practice of art in support of it. Given that the objections I discuss miss their target, and given the observations in support of it, I conclude that the Affective View is worth serious reconsideration. (shrink)

According to tradition, aesthetic value is non-contingently connected to a certain feeling of liking or pleasure. Is that true? Two answers are on offer in the field of aesthetics today: 1. The Hedonist answers: Yes, aesthetic value is non-contingently connected to pleasure insofar as this value is constituted and explained by the power of its possessors to please (under standard conditions). 2. The Non-Affectivist answers: No. At best, pleasure is contingently related to aesthetic value. The aim of this paper is (...) to point to a blind spot in the dialectic between these two standard positions by defending a third neglected answer to the question above, the answer of the Value-Meriting-Pleasure [VMP] advocate. According to this answer, a certain kind of (cognitive and responsive) pleasure is connected to aesthetic value non-contingently, but also non-hedonically. VMP is the view that objects of aesthetic value are non-contingently related to pleasure insofar as they merit a certain kind of pleasure. But, pace the hedonist, those objects are valuable (those that are to be engaged with etc.) neither on account of their capacity to give pleasure nor on account of the hedonic value of the attitude they merit. (shrink)

What is the source of aesthetic knowledge? Empirical knowledge, it is generally held, bottoms out in perception. Such knowledge can be transmitted to others through testimony, preserved by memory, and amplified via inference. But perception is where the rubber hits the road. What about aesthetic knowledge? Does it too bottom out in perception? Most say “yes”. But this is wrong. When it comes to aesthetic knowledge, it is appreciation, not perception, where the rubber hits the road. The ultimate source of (...) aesthetic knowledge is feeling. In this essay, we articulate and defend the very idea of affective knowledge and reveal aesthetic knowledge to be a species of the genus. We then show how the view resolves a thorny problem that has bedeviled aesthetic epistemologists: how to reconcile the seemingly direct character of aesthetic knowledge with the possibility of acquiring such knowledge from criticism. One learns from criticism, we argue, when it guides one’s engagement with an object so that one can appreciate it in virtue of those of its features that render it worthy of appreciation. (shrink)

There is a debate about whether particular properties are for Aristotle non-recurrent and trope-like individuals or recurrent universals. I argue that Physics I.7 provides evidence that he took non-substantial particulars to be neither; they are instead non-recurrent modes. Physics I.7 also helps show why this matters. Particular properties must be individual modes in order for Aristotle to preserve three key philosophical commitments: that objects of ordinary experience are primary substances, that primary substances undergo genuine change, and that primary substances are (...) ontologically fundamental. (shrink)

Recently, various philosophers have argued that we can obtain knowledge via the imagination. In particular, it has been suggested that we can come to know concrete, empirical matters of everyday significance by appropriately imagining relevant scenarios. Arguments for this thesis come in two main varieties: black box reliability arguments and constraints-based arguments. We suggest that both strategies are unsuccessful. Against black-box arguments, we point to evidence from empirical psychology, question a central case-study, and raise concerns about a (claimed) evolutionary rationale (...) for the imagination's reliability. Against the constraints-based account, we argue that to the extent that it works, this does not give rise to knowledge that is distinctively from the imagination. We conclude by suggesting that the imagination's role in raising possibilities, traditionally seen as part of the context of discovery, can in fact play a role in justification, including as a bulwark against certain sorts of skepticism. (shrink)

Evolutionary debunking arguments appeal to selective etiologies of human morality in an attempt to undermine moral realism. But is morality actually the product of evolution by natural selection? Although debunking arguments have attracted considerable attention in recent years, little of it has been devoted to whether the underlying evolutionary assumptions are credible. In this paper, we take a closer look at the evolutionary hypotheses put forward by two leading debunkers, namely Sharon Street and Richard Joyce. We raise a battery of (...) considerations, both empirical and theoretical, that combine to cast doubt on the plausibility of both hypotheses. We also suggest that it is unlikely that there is in the vicinity a plausible alternative hypothesis suitable for the debunker’s cause. (shrink)

I distinguish three theses associated with the new mechanistic philosophy – concerning causation, explanation and scientific methodology. Advocates of each thesis are identified and relationships among them are outlined. I then look at some recent work on natural selection and mechanisms. There, attention to different kinds of New Mechanism significantly affects of what is at stake.

Until very recently, there has been no discussion of aesthetic agency. This is likely because aesthetics has traditionally focused not on action, but on appreciation, while the standard approach identifies ‘agency’ with the will, and, more specifically, with the capacity for intentional action. In this paper, I argue, first, that this identification is unfortunate since it fails to do justice to the fact that we standardly attribute beliefs, emotions, desires, and other conative and affective attitudes that aren’t formed ‘at will,’ (...) including aesthetic appreciation, to people’s agency. Fortunately, we need not abide by this Practical Approach, but can develop an alternative: the Authority Approach to rational agency, which does justice to the widespread practice of rationally assessing, reactively responding to, and holding people responsible for non-voluntary attitudes. This is very good news for aesthetics since, I argue additionally, any account of aesthetic agency that accepts the Practical Approach, and focuses on aesthetic actions fails to provide a genuine notion of aesthetic agency. For we have no handle on what counts as aesthetic actions independently of these actions’ relation to appreciation: actions are “aesthetic” only derivatively insofar as they center around those that merit (dis)appreciation. For this reason, we have genuine aesthetic agency only if we can exercise agency in acts of the rational-affective capacity for appreciation, which differs from the will. The Authority Approach allows us to explain how we exercise agency in aesthetic appreciations, thus equipping us with a genuine conception of aesthetic agency. (shrink)

The Hodgkin–Huxley (HH) model of the action potential is a theoretical pillar of modern neurobiology. In a number of recent publications, Carl Craver ([2006], [2007], [2008]) has argued that the model is explanatorily deficient because it does not reveal enough about underlying molecular mechanisms. I offer an alternative picture of the HH model, according to which it deliberately abstracts from molecular specifics. By doing so, the model explains whole-cell behaviour as the product of a mass of underlying low-level events. The (...) issue goes beyond cellular neurobiology, for the strategy of abstraction exhibited in the HH case is found in a range of biological contexts. I discuss why it has been largely neglected by advocates of the mechanist approach to explanation. 1 Introduction2 A Primer on the HH Model2.1 The basic qualitative picture2.2 The quantitative model3 Interlude: What Did Hodgkin and Huxley Think?4 Craver’s View4.1 Mechanistic explanation4.2 Sketches4.3 Craver's view: The HH model as a mechanism sketch5 An Alternative View of the HH Model5.1 Another look at the equations5.2 The discrete-gating picture5.3 The road paved by Hodgkin and Huxley5.4 Summary and comparison to Craver6 Conclusion: The HH Model and Mechanistic Explanation6.1 Sketches and abstractions6.2 Why has aggregative abstraction been overlooked? (shrink)

Many biological investigations are organized around a small group of species, often referred to as ‘model organisms’, such as the fruit fly Drosophila melanogaster. The terms ‘model’ and ‘modelling’ also occur in biology in association with mathematical and mechanistic theorizing, as in the Lotka–Volterra model of predator-prey dynamics. What is the relation between theoretical models and model organisms? Are these models in the same sense? We offer an account on which the two practices are shown to have different epistemic characters. (...) Theoretical modelling is grounded in explicit and known analogies between model and target. By contrast, inferences from model organisms are empirical extrapolations. Often such extrapolation is based on shared ancestry, sometimes in conjunction with other empirical information. One implication is that such inferences are unique to biology, whereas theoretical models are common across many disciplines. We close by discussing the diversity of uses to which model organisms are put, suggesting how these relate to our overall account. 1 Introduction2 Volterra and Theoretical Modelling3 Drosophila as a Model Organism4 Generalizing from Work on Model Organisms5 Phylogenetic Inference and Model Organisms6 Further Roles of Model Organisms6.1 Preparative experimentation6.2 Model organisms as paradigms6.3 Model organisms as theoretical models6.4 Inspiration for engineers6.5 Anchoring a research community7 Conclusion. (shrink)

A long debate in aesthetics concerns the reasoned nature of criticism. The main questions in the debate are whether criticism is based on (normative) reasons, whether critics communicate reasons for their audience’s responses, and if so, how to understand these critical reasons. I argue that a great obstacle to making any progress in this debate is the deeply engrained assumption, shared by all sides of the debate, that reasons can only be either theoretical reasons (i.e., those that explain what to (...) believe or what propositions are true) or practical reasons (i.e., those that explain what is to be done or what actions are good/required/called for/otherwise worthy of doing). My aims are (1) to put pressure on this assumption that, if there are critical reasons, they must be either theoretical or practical (the EITHER/OR assumption), and (2) to suggest that, if there are critical reasons, the most central among them are neither theoretical nor practical (NEITHER/NOR). (shrink)

This paper derives from a broader project dealing with the notion of causal order. I use this term to signify two kinds of parts-whole dependence: Orderly systems have rich, decomposable, internal structure; specifically, parts play differential roles, and interactions are primarily local. Disorderly systems, in contrast, have a homogeneous internal structure, such that differences among parts and organizational features are less important. Orderliness, I suggest, marks one key difference between individuals and collectives. My focus here will be the connection between (...) order and robustness, i.e. functional resilience in the face of internal or environmental perturbations. I distinguish three varieties of robustness. Ordered robustness is grounded in the system’s specific organizational pattern. In contrast, disorderly robustness stems from the aggregate outcome of many similar parts. In between, we find semi-ordered robustness, wherein a messy ensemble of elements is subjected to a selection or stabilization mechanism. I give brief characterizations of each category, discuss examples and remark on the connection between the order/disorder axis and the notions of individual versus collective. (shrink)

Moral realism is often taken to have common sense and initial appearances on its side. Indeed, by some lights, common sense and initial appearances underlie all the central positive arguments for moral realism. We offer a kind of debunking argument, taking aim at realism’s common sense standing. Our argument differs from familiar debunking moves both in its empirical assumptions and in how it targets the realist position. We argue that if natural selection explains the objective phenomenology of moral deliberation and (...) judgement, then this undermines arguments from that phenomenology. This results in a simpler, and in some ways more direct, challenge to realism. It is also less vulnerable to the main objections that have been leveled against such arguments. If accepted, our conclusion should make a real difference to the dialectic in this area. It means that neither realism nor its denial is the default, to-be-refuted, position. (shrink)

Some philosophers of science – the present author included – appeal to fiction as an interpretation of the practice of modeling. This raises the specter of an incompatibility with realism, since fiction-making is essentially non-truth-regulated. I argue that the prima facie conflict can be resolved in two ways, each involving a distinct notion of fiction and a corresponding formulation of realism. The main goal of the paper is to describe these two packages. Toward the end I comment on how to (...) choose among them. (shrink)

The main claim of the paper is that, on Kant's account, aesthetic pleasure is an exercise of rational agency insofar as, when proper, it has the following two features: (1) It is an affective responsiveness to the question: “what is to be felt disinterestedly”? As such, it involves consciousness of its ground (the reasons for having it) and thus of itself as properly responsive to its object. (2) Its actuality depends on endorsement: actually feeling it involves its endorsement as an (...) attitude to have. I claim that seeing that nature of aesthetic pleasure requires that we divest ourselves of the following dilemma: either feelings are the non-cognitive, passive ways through which we are affected by objects; or they are cognitive states by virtue of the theoretical beliefs they necessarily involve. On my reading of Kant, this dilemma is false. Aesthetic pleasure is neither passive, nor theoretically cognitive, and yet, it is an exercise of rational agency by virtue of belonging to a domain of rationality that is largely overlooked in the history of philosophy, but that deserves, I argue following Kant, our close attention: aesthetic rationality. In the first section, I explain this nature of aesthetic pleasure, and in the second section, I respond to a charge of “over-intellectualism.". (shrink)

The main task of the paper is to explore Kant’s understanding of what unites the three kinds of judgment that he regards as the signature judgments of the three fundamental faculties of the mind--theoretical, practical and aesthetic judgments--in a way that preserves their fundamental differences. I argue that these are differences in kind not only in degree; or, in the terms I motivate in the paper, differences in form. Thus, I aim to show that (1) the Romantic unity of knowing, (...) doing, and enjoying is not only inspired by Kant, but is in Kant’s own writings, and that (2) Kant understands this unity as a unity within a categorical variety: for him, theoretical judgment, practical judgment, and aesthetic judgment are the paradigmatic judgments of three formally different and irreducible rational capacities. I argue that a chief component in understanding the unity in this multiplicity is the imagination. This is because lawfulness turns out to be an essential mark of the “high” or “rational” aspects of the mind. But, for Kant, human beings can be lawful, and thus rational, in and of their world, only insofar as they are also imaginative. It is the imagination that allows us to be rational in our empirical world: to be rational animals. (shrink)

Many have expected that understanding the evolution of norms should, in some way, bear on our first-order normative outlook: How norms evolve should shape which norms we accept. But recent philosophy has not done much to shore up this expectation. Most existing discussions of evolution and norms either jump headlong into the is/ought gap or else target meta-ethical issues, such as the objectivity of norms. My aim in this paper is to sketch a different way in which evolutionary considerations can (...) feed into normative thinking—focusing on stability. I will discuss two forms of argument that utilize information about social stability drawn from evolutionary models, and employs it to assess claims in political philosophy. One such argument treats stability as feature of social states that may be taken into account alongside other features. The other uses stability as a constraint on the realization of social ideals, via a version of the ought-implies-can maxim. These forms of argument are not new; indeed they have a history going back at least to early modern philosophy. But their marriage with evolutionary information is relatively recent, has a significantly novel character, and has received little attention in recent moral and political philosophy. (shrink)

While I welcome Mohan Matthen’s insistence that art is connected to aesthetic pleasure, I worry about his commitment to viewing pleasure as prior to, and constitutive of, the value of art. I raise my reservations by (i) dispelling his criticism of the reversed explanatory direction, and (ii) showing problems for his commitment. As an alternative, I offer an account of pleasure that explains it in terms of the independent value of art—an account that is free of the problems Matthen raises (...) against this explanatory approach. (shrink)

Friedrich Schlegel’s remarks about poetry and reality are notoriously baffling. They are often regarded as outlandish, or “poetically exaggerated” statements, since they are taken to suggest that there is no difference between poetry and reality or to express the view that there is no way out of linguistic and poetic constructions (Bowie). I take all these responses to be mistaken, and argue that Schlegel’s remarks are philosophical observations about a genuine confusion in theoretical approaches to the distinction between fiction and (...) reality. The confusion at stake involves the assumption that this distinction is and must be fixed independently of the ordinary practices of using these terms to mean certain things in specific situations. And this assumption itself is grounded fundamentally in a confused picture about the way language works. I argue that this confused understanding of the distinction between fiction and reality is not an object of the past, but a picture that is still shaping a central strand in the contemporary debate in philosophical aesthetics about our emotional responses to fiction. And while I do not use Schlegel’s approach to argue against this contemporary view directly, I suggest that his philosophical method includes the resources for unraveling a central confusion in this contemporary debate. (shrink)

The aim of this paper is to elucidate what Kant describes as the "free lawfulness of the imagination" in judgments of beauty in aesthetic terms, as called for by the distinctive nature of beauty. I argue that the aesthetic activity of the imagination differs from the theoretical activity of the imagination, and that the difference between the two has an aesthetic ground in terms of the special form of beautiful objects and the special value of beauty. In contrast to the (...) theoretical activity of the imagination, the aesthetic activity of the imagination must be free of concepts and laws but nonetheless lawful otherwise it would not be able to unify the forms of beautiful objects, to attribute necessity to them, and by so doing to be adequate to the value of those objects as beautiful objects. On that basis, I aim to show that Kant's theory is not committed to the absurd view that some scholars have attributed to him: the view that everything we judge must be judged to be beautiful. (shrink)

According to [Bayesian] models” in cognitive neuroscience, says a recent textbook, “the human mind behaves like a capable data scientist”. Do they? That is to say, do such model show we are rational? I argue that Bayesian models of cognition, perhaps surprisingly, do not and indeed cannot, show that we are Bayesian-rational. The key reason is that such models appeal to approximations, a fact that carries significant implications. After outlining the argument, I critique two responses, seen in recent cognitive neuroscience. (...) One says that the mind can be seen as approximately Bayes-rational, while the other reconceives norms of rationality. (shrink)

The study of biological altruism is a cornerstone of modern evolutionary biology. Associated with foundational issues about natural selection, it is often supposed that explaining altruism is key to understanding social behavior more generally. Typically, biological altruism is defined in purely effects-based, behavioral terms – as an interaction in which one organism contributes fitness to another, at its own expense. Crucially, such a definition isn’t meant to rest on psychological or intentional assumptions. We show that, appearances and official definitions notwithstanding, (...) the notion biological altruism carries a vestige of the psychological, intentional concept familiar to us from the human domain. In particular, definitions of altruism from Hamilton onwards presuppose an actor\recipient distinction – a distinction, so we argue, that has questionable biological grounding. We arrive at this conclusion step-by-step, first looking at several simple, “austere” definitions and their problems, and then critiquing the actor\recipient distinction directly. If successful, our arguments suggest that the category of biological altruism requires a significant rethink. (shrink)

Evolutionary debunking arguments (EDAs) have attracted extensive attention in meta-ethics, as they pose an important challenge to moral realism. Mogensen (2015) suggests that EDAs contain a fallacy, by confusing two distinct forms of biological explanation – ultimate and proximate. If correct, the point is of considerable importance: evolutionary genealogies of human morality are simply irrelevant for debunking. But we argue that the actual situation is subtler: while ultimate claims do not strictly entail proximate ones, there are important evidential connections between (...) the two. Attending to these connections clears ground for a new and improved EDA. However, it also brings into view some possible problems with EDAs that have been largely neglected so far. (shrink)

In "Torts, Egalitarianism and Distributive Justice" , Tsachi Keren-Paz presents impressingly detailed analysis that bolsters the case in favour of incremental tort law reform. However, although this book's greatest strength is the depth of analysis offered, at the same time supporters of radical law reform proposals may interpret the complexity of the solution that is offered as conclusive proof that tort law can only take adequate account of egalitarian aims at an unacceptably high cost.

This document presents a Gentzen-style deductive calculus and proves that it is complete with respect to a 3-valued semantics for a language with quantifiers. The semantics resembles the strong Kleene semantics with respect to conjunction, disjunction and negation. The completeness proof for the sentential fragment fills in the details of a proof sketched in Arnon Avron (2003). The extension to quantifiers is original but uses standard techniques.