A class of problems is called decidable if there is an algorithm which will give the answer to any problem of the class after a finite length of time. The purpose of this paper is to discuss the classes of problems that can be solved by infinitely long decision procedures in the following sense: An algorithm is given which, for any problem of the class, generates an infinitely long sequence of guesses. The problem will be said to be solved in (...) the limit if, after some finite point in the sequence, all the guesses are correct and the same. Functions, sets, and functionals which are decidable by such infinite algorithms will be calledlimiting recursive. These, together with classes of objects which can beidentified in the limit, are the subjects of this report.Without qualification,setwill mean set of numbers;functionwill mean number-theoretic function of 1 variable, possibly partial;functionalswill take numerical values and have any number of numerical and/or function variables, the latter ranging solely over total functions of 1 variable. Thus a function is a special case of a functional,xwill invariably stand for a numerical variable;φfor a function variable;gfor a guess ;nfor the numerical variable which indexes the guesses, referred to as thetime. (shrink)

Much international debate over access to medicines focuses on whether patent law accords with international human rights law. This article argues that this is the wrong question to ask. Following an analysis of both patent and human rights law, this article suggests that the better approach is to focus on national debates over the best calibration of patent law to achieve national objectives.

Patents and free trade make strange bedfellows. For most of their history, patents have been instruments deployed to resist trade with other countries, not to enhance it. Whether one looks at Venetian laws that punished citizens who practiced local crafts outside the city, the Mercantilist uses to which patents were put in Elizabethan England, or the cartels of the 19th and 20th centuries created on a foundation of interlocking patent rights, patents have had a distinctly protectionist function. It is thus (...) ironic that it is intellectual property rights in general, and patents in particular, that have been held up in recent years as the poster child of much that is wrong with globalization and free trade. Nowhere is this more so than in debates concerning international human rights law and patents, in particular the position that patents violate an international right to health. (shrink)

Software plays an important role in contemporary research. Aside from its use for administering traditional instruments like surveys and in data analysis, the widespread use of mobile and web apps for social, medical and lifestyle engagement has led to software becoming a research intervention in its own right. For example, it is not unusual to find apps being studied for their utility as interventions in health and social life. Since the software may persist in use beyond the life of an (...) investigation, this raises questions as to the extent of ethical duties for researchers involved in its production and/or study towards the participants involved. Key factors identified include the extent of affect created by the software, the effect it has on a participant’s life, the length of investigation, cost of maintenance and participant agency. In this article we discuss the issues raised in such situations, considering them in the context of post-research duties of care and suggesting strategies to balance the burden on researchers with the need for ongoing participant support. (shrink)

Organisations have implemented intensive home-based teleworking in response to global COVID-19 lockdowns and other pandemic-related restrictions. Financial pressures are driving organisations to continue intensive teleworking after the pandemic. Understanding employees’ teleworking inclinations post COVID-19, and how these inclinations are influenced by different factors, is important to ensure any future, more permanent changes to teleworking policies are sustainable for both employees and organisations. This study, therefore, investigated the relationships between the context of home-based teleworking during the pandemic, productivity perceptions during home-based (...) teleworking, and employees’ future teleworking inclinations beyond the pandemic. Specifically, the study examined whether pandemic-teleworking conditions related to the job, and the physical and social environments at home, influenced employees’ FTI, and if perceptions of improved or reduced productivity mediated these relationships. Data were collected during April and May 2020 with a cross-sectional online survey of teleworkers in Germany, Switzerland, the United Kingdom, and other countries during the first COVID-19 lockdowns. Reported FTI were mixed. Most participants reported wanting to telework more post-pandemic compared to before the pandemic; however, 18% wanted to telework less. Hierarchical multiple regression analysis revealed that some teleworking conditions were positively associated with FTI. Other teleworking conditions were not associated with FTI. Perceived changes in productivity mediated the relationship between work privacy fit and FTI. Findings highlight the role of work privacy fit and job demands in influencing pandemic productivity perceptions and teleworking inclinations post-pandemic. Results raise questions about the suitability and sustainability of home-based teleworking for all staff. As organisations plan to increase the proportion of teleworking post-pandemic, this study suggests there is a need to support employees who perceived their productivity to be poor while home-working during the pandemic. (shrink)

Despite the frequency of stillbirths, the subsequent implications are overlooked and underappreciated. We present findings from comprehensive, systematic literature reviews, and new analyses of published and unpublished data, to establish the effect of stillbirth on parents, families, health-care providers, and societies worldwide. Data for direct costs of this event are sparse but suggest that a stillbirth needs more resources than a livebirth, both in the perinatal period and in additional surveillance during subsequent pregnancies. Indirect and intangible costs of stillbirth are (...) extensive and are usually met by families alone. This issue is particularly onerous for those with few resources. Negative effects, particularly on parental mental health, might be moderated by empathic attitudes of care providers and tailored interventions. The value of the baby, as well as the associated costs for parents, families, care providers, communities, and society, should be considered to prevent stillbirths and reduce associated morbidity. (shrink)

© 2015 Elsevier Inc.Toxoplasma gondii is a protozoan pathogen in the phylum Apicomplexa that resides within an intracellular parasitophorous vacuole that is selectively permeable to small molecules through unidentified mechanisms. We have identified GRA17 as a Toxoplasma-secreted protein that localizes to the parasitophorous vacuole membrane and mediates passive transport of small molecules across the PVM. GRA17 is related to the putative Plasmodium translocon protein EXP2 and conserved across PV-residing Apicomplexa. The PVs of GRA17-deficient parasites have aberrant morphology, reduced permeability to (...) small molecules, and structural instability. GRA17-deficient parasites proliferate slowly and are avirulent in mice. These GRA17-deficient phenotypes are rescued by complementation with Plasmodium EXP2. GRA17 functions synergistically with a related protein, GRA23. Exogenous expression of GRA17 or GRA23 alters the membrane conductance properties of Xenopus oocytes in a manner consistent with a large non-selective pore. Thus, GRA17 and GRA23 provide a molecular basis for PVM permeability and nutrient access. (shrink)

We agree with Shors & Matzel's general hypothesis that the proposed link between NMDA-dependent LTP and memory is weak. They suggest that NMDA-dependent LTP is important to arousal or attentional processes which influence learning in an anterograde manner. However, current evidence is also consistent with the view that NMDA receptors modulate memory consolidation retroactively, as occurs in several other receptor classes.

We study how an organization’s error-management climate affects organizational members’ beliefs about other members’ willingness to report errors that they discover when chance of error detection by superiors and others is extremely low. An error-management climate, as a component of the organizational climate, is said to be “high” when errors are accepted as part of everyday life as long as they are learned from and not repeated. Alternatively, the error-management climate is said to be an “error averse” climate when discovery (...) of errors invokes the laying of blame on those admitting to or found committing errors. We examine the effects of this error-management climate in a professional services environment where uncorrected errors may have severe consequences and discovery of work errors is crucial for organizational success. We find that error-management climate affects organizational members’ beliefs about what other members will report about discovered self-made errors, with a high error-management (versus error averse) climate leading to greater reporting willingness. We also find a significant interaction with a key contextual variable, error type (conceptual or calculation), that suggests the effect is more significant for conceptual errors than calculation errors. Our findings suggest that an organization’s error-management climate is an important factor in promoting ethical behavior of employees, especially junior employees, carrying out routine tasks whose failure to report errors discovered incidental to those tasks may have severe implications for their organizations. (shrink)

The rejection of behaviorism in the 1950s and 1960s led to the view, due mainly to Noam Chomsky, that language must be studied by looking at the mind and not just at behavior. It is an understatement to say that Chomskyan linguistics dominates the field. Despite being the overwhelming majority view, it has not gone unchallenged, and the challenges have focused on different aspects of the theory. What is almost universally accepted, however, is Chomsky’s view that understanding language demands a (...) theory that posits mental states that represent rules of language. Call this claim, following Cowie (1999), Representationalism or (R). According to (R), ‘‘[e]xplaining language mastery and acquisition requires the postulation of contentful mental states and processes involving their manipulation’’ (Cowie, 1999, p. 154). Although (R) is nothing more than the general assumption on which cognitive psychology is founded applied to the case of language, even it has had its detractors. Critics have argued that linguistic competence should not in fact be thought of as based on the possession of a body of linguistic knowledge but should be thought of, rather, as a kind of skill. This is an important challenge because one might be inclined to think that no recognizable form of Chomskyan linguistics could withstand the falsification of (R). In this paper we attempt to show that in fact (R) could be false without doing much damage to Chomskyan linguistics at all. Indeed, it is possible that the Chomskyan position could be made more coherent by adopting the view we will sketch. Our claim, therefore, is that critics of (R) might be right, but that this does not obviously make them serious critics of the Chomskyan program. (shrink)

This article addresses learning in desktop virtual worlds where students role play for professional education. When students role play in such virtual worlds, they can learn some knowledge and skills that are useful in the physical world. However, existing learning theories do not provide a plausible explanation of how performing non-verbal virtual world actions (e.g. performing a virtual chest examination in a virtual hospital) can lead to the learning of the physical world equivalent. Some theories are particularly implausible because they (...) claim that students learn to perform physical world actions by acting on the virtual world in an embodied way. This is implausible because learning requires a high degree of correspondence between the learning performance and the target performance, and there is insufficient physical correspondence between the performance of a virtual world action where students click on a mouse to make the avatar take actions and the physical-world equivalent where students perform the action with their own body. In this article, we use Austin’s speech act theory to provide a more plausible theory of learning in virtual worlds. We show how non-verbal virtual-world actions performed by avatars can function as performatives and as performatives, they can correspond sufficiently to physical world actions to explain how performing non-verbal virtual-world actions can lead to physical world learning. (shrink)

A framing effect occurs when an agent's choices are not invariant under changes in the way a decision problem is presented, e.g. changes in the way options are described (violation of description invariance) or preferences are elicited (violation of procedure invariance). Here we identify those rationality violations that underlie framing effects. We attribute to the agent a sequential decision process in which a “target” proposition and several “background” propositions are considered. We suggest that the agent exhibits a framing effect if (...) and only if two conditions are met. First, different presentations of the decision problem lead the agent to consider the propositions in a different order (the empirical condition). Second, different such “decision paths” lead to different decisions on the target proposition (the logical condition). The second condition holds when the agent's initial dispositions on the propositions are “implicitly inconsistent,” which may be caused by violations of “deductive closure.” Our account is consistent with some observations made by psychologists and provides a unified framework for explaining violations of description and procedure invariance. (shrink)

In the "cratylus", Plato presents two theories about the correctness of names, I.E., Names are correct by nature and names are correct by convention. In this paper, I argue that plato holds both views because he recognizes that the word 'name' is ambiguous as between type and token. Name tokens (individual strings of marks and noises) are conventional for plato. But name types (the role played by the tokens or the concept expressed by the tokens) are not conventional for plato.

Trust can be thought of as a three place relation: A trusts B to do X. Trustworthiness has two components: competence (does the trustee have the relevant skills, knowledge and abilities to do X?) and willingness (is the trustee intending or aiming to do X?). This chapter is about the willingness component, and the different motivations that a trustee may have for fulfilling trust. The standard assumption in economics is that agents are self-regarding, maximizing their own consumption of goods and (...) services. This is too restrictive. In particular, people may be concerned with the outcomes of others, and they may be concerned to follow ethical principles. I distinguish weak trustworthiness, which places no restrictions on B’s motivation for doing X, from strong trustworthiness, where the behaviour must have a particular non-selfish motivation, in finance the fiduciary commitment to promote the interests of the truster. I discuss why strong trustworthiness may be more efficient and also normatively preferable to weak. In finance, there is asymmetric information between buyer and seller, which creates a need for trustworthy assessment of products. It also creates an ambiguity about whether the relationship is one of buyer and seller, governed by caveat emptor, or a fiduciary relationship of advisor and client. This means that there are two possible reasons why trust may be breached: because the trustee didn’t realise that the truster framed the relationship as a fiduciary one, or because the trustee did realise but actively sought to take advantage of the trust. Correspondingly, there are two possible types of agent: normal people who are not always self-regarding and who are trust responsive (if they believe that they are being trusted then they are likely to fulfill that trust), and knaves, after Hume’s character who is always motivated by his own private interest. We can increase the trustworthiness of normal people by getting them to re-frame the situation as one of trust, so they will be strongly trustworthy (i.e. change of institutional culture), and by providing non-monetary incentives (the correct choice of incentive will depend on exactly what their non-selfish motivation is). Knaves need sanctions, which can make them weakly trustworthy. However, this is a delicate balance because sanctions can crowd out normative frames. We can also increase the trustworthiness of financiers by making finance less attractive to knaves; changing the mix of types in finance could help support the necessary cultural change. (shrink)

Background Physical morbidity is rife among patients with serious mental illness. When they are involuntarily hospitalized and even treated, they may still refuse treatment for physical illness leading clinicians to wonder about the ethics of coercing such treatments. Research aim This survey study explored psychiatric caregivers’ perceptions on whether compulsory treatment of physical illness is legal and whether it is justifiable in patients with serious mental illness and under what circumstances. Research design A questionnaire that included two case vignettes of (...) an involuntarily hospitalized psychiatric patient with diabetes refusing treatment with insulin for various reasons. The cases differed in terms of diabetes severity. Participants answered questions regarding the appropriateness of involuntary treatment. Participants and research context Psychiatric medical doctors and nurses working in a mental health center. ( N = 89, 50 female, ages 26–66). Ethical considerations The study was approved by the Medical Centre Institutional Review Board (IRB) and the University Ethics Committee. The respondents’ anonymity was kept. Participation was voluntary and consent was obtained. Results The severity of the patient’s medical condition and their reason for refusing treatment were associated with participants’ willingness to give insulin despite patient objection [( F(1, 87) = 49.41, p <.01; ( F(1, 87) = 33.44, p <.01), respectively]. Participants were more inclined to support compulsory treatment if the patient’s refusal was “illness-oriented” (i.e. directly related to psychiatric illness). Participants presented diverse views regarding the perceived legality of compulsory treatment of physical illness in such situations (illegal 63.09%; legal 23.8%; 13% unsure). The majority (53.5%–55.3%) of those who thought it was illegal supported compulsory treatment in high-severity, illness-oriented refusal situations. Conclusions The severity of the medical condition and the reason for treatment refusal influence psychiatric caregivers’ willingness to provide compulsory treatment for physical illness in involuntary hospitalized psychiatric patients. Beyond the legal framework, ethical guidelines for these situations are warranted, while decisions should be made on a case-by-case basis. (shrink)

After a brief discussion of altruism, supererogation, and the duty to rescue in American and Jewish Law, this paper turns to an examination of the challenge to altruism presented by the developing field of evolutionary psychology. Evolutionary psychology is the investigation of animal behavior from the perspective of natural selection. The fundamental issue, as E.O. Wilson says, is the question, "How can altruism, which by definition reduces personal fitness, possibly evolve by natural selection?" According to a seminal article in the (...) field, "Models that attempt to explain altruistic behavior in terms of natural selection are models designed to take the altruism out of altruism." The challenge of evolutionary psychology is that it provides a "genealogy of morals" that many have found to be disturbing. From the evolutionary perspective what crucially matters is the reproductive success of the individual animal, the transmission of its genes to later generations, and this provides the measure of its individual fitness. The evolutionary psychologist's argument proceeds by the introduction of three basic concepts: kin selection , reciprocal altruism, and indirect reciprocity. Each of these concepts is critically analyzed. It is concluded that the current status of altruism and cooperation is not affected by evolutionary history. They do have a genetic basis, but then so does everything about human beings, nastiness as well as cooperation; it does not follow that motives for cooperation are always self-serving. Nach einer kurzen Erörterung von Altruismus, Supererogation und der Hilfeleistungspflicht im amerikanischen und jüdischen Recht wendet sich der Artikel einer Untersuchung der Anforderungen zu, die die Evolutionspsychologie an den Altruismus stellt. Evolutionspsychologie ist die Erforschung tierischen Verhaltens aus der Perspektive der natürlichen Auslese. Das grundlegende Problem ist, wie E.O. Wilson sagt, die Frage: "Wie kann sich Altruismus, der per definitionem die eigenen Fähigkeiten vermindert, durch natürliche Auslese entwickeln?" Nach einem bahnbrechenden Artikel sind "Modelle, die versuchen, altruistisches Verhalten in Begriffen der natürlichen Auslese zu erklären, darauf angelegt, dem Altruismus das Altruistische zu nehmen". Die Herausforderung der Evolutionspsychologie ist die von ihr bereitgestellte "Genealogie der Sitten", die von vielen als eine Beeinträchtigung empfunden wird. Vom Standpunkt der Evolution kommt es entscheidend auf den Reproduktionserfolg des einzelnen Wesens an, auf die Übertragung seiner Gene auf spätere Generationen, und das liefert den Maßstab für seine eigenen Fähigkeiten. Die Argumentation der Evolutionspsychologen fährt mit der Einführung von drei grundlegenden Begriffen fort: "kin selection" , reziproker Altruismus und indirekte Reziprozität. Jeder dieser Begriffe wird kritisch analysiert. Daraus folgt, daß der gegenwärtige Stand von Altruismus und Kooperation von der Evolutionsgeschichte nicht beeinflußt ist. Altruismus und Kooperation haben eine genetische Basis. Aber das haben alle menschlichen Eigenschaften, Bosheit genauso wie Kooperation. Daraus folgt nicht, daß die Motive für Kooperation stets dem Handelnden dienen. (shrink)

Neurons are now known to produce a variety of types of chemical transmitters. Classical transmitters are stored within synaptic vesicles which undergo synaptic exocytosis in association with presynaptic thickenings. The larger, dense‐cored secretory granules present in most neurons contain neuropeptides and mainly discharge their contents at morphologically undifferentiated (i.e.nonsynaptic) sites. The synaptic character of vesicle discharge enables transmitters to exercise a highly focal action, whereas nonsynaptic release probably relates to the slow rate of degradation of many neuropeptides and their consequent (...) widespread diffusion and sphere of action. However, one variant of the basic pattern, involving the restriction of granule discharge to areas of the terminal plasmalemma situated adjacent to the postsynaptic cells (i.e. a parasynaptic configuration), enables a degree of targeted peptide discharge to be achieved. The diversity of patterns of neural exocytosis adds a further dimension to the complexity of nervous function. (shrink)

This essay reviews John Gardner’s recent books, From Personal Life to Private Law, and Torts and Other Wrongs. Both books offer profound insights into private law’s concerns with justice and our reasons for action. The essay focuses on Gardner’s continuity thesis, and in particular on his idea that a third party may act on behalf of a wrongdoer as her delegee. Three settings are considered. First, I will discuss settings in which the state or another third party acts to remedy (...) a wrong without the wrongdoer’s consent. Second, I will review settings in which the legal remedies at issue – e.g., general damages or punitive damages – may not fit well with the idea that the state is acting on behalf of a wrongdoer. Third, I will analyze settings in which the state may be acting on behalf of right holders, yet still be concerned with the continuity thesis. Assessing each of these contexts offers further insights into the purpose of private law remedies. (shrink)

In Plato’s early dialogues, Socrates frequently asks questions of the form “What is X?” seeking definitions of the substitution instances of X (e.g., Justice, Piety, and Courage). In attempting to elucidate Socratic definition, a number of interpreters have invoked a distinction between real and nominal definition (the distinction between the definition of a thing and the definition of a word. In using that distinction, several interpreters have pointed out that, when Socrates asked his “What is X” question (e.g., “What is (...) Justice?”), he was not seeking a nominal definition (a definition of the word ‘διχαιοσύνή’), but rather a real definition (a definition of the thing, Justice). My purpose in this paper is to argue that the preceding interpretation of Socratic thought is mistaken, i.e., I shall argue that there is no real/nominal distinction to be found in the Socratic dialogues. (shrink)

In Plato’s early dialogues, Socrates frequently asks questions of the form “What is X?” seeking definitions of the substitution instances of X (e.g., Justice, Piety, and Courage). In attempting to elucidate Socratic definition, a number of interpreters have invoked a distinction between real and nominal definition (the distinction between the definition of a thing and the definition of a word. In using that distinction, several interpreters have pointed out that, when Socrates asked his “What is X” question (e.g., “What is (...) Justice?”), he was not seeking a nominal definition (a definition of the word ‘διχαιοσύνή’), but rather a real definition (a definition of the thing, Justice). My purpose in this paper is to argue that the preceding interpretation of Socratic thought is mistaken, i.e., I shall argue that there is no real/nominal distinction to be found in the Socratic dialogues. (shrink)

This essay considers the eighth century Indian Buddhist monk, Śāntideva’s strategy of using the afflictive mental states for progress towards liberation in his Introduction to the Practice of Awakening. I begin by contrasting two images from the first chapter that represent the power of bodhicitta: the fires destroying the universe at the end of time, and the mercury elixir that transmutes base metals into gold. The first of these, I argue, better illustrates the text’s predominant strategy of destroying the afflictive (...) mental states directly by their antidotes. The second, in contrast, represents an alternative strategy in which afflictive mental states like anger, craving and delusion, are manipulated for liberative gain. I offer several examples of Śāntideva’s use of the kleśas in his text, and argue that they can be understood as a continuation of the logic of skillful means, in which destructive actions, and here destructive mental states, are used to lessen suffering. Finally, I suggest that one reason Śāntideva employs the kleśas in this way is because of his realization that many practitioners early on the bodhisattva path will lack the motivation necessary to successfully pursue the difficult training of the bodhisattva. (shrink)

This is the first comprehensive translation of the expanded French version of E.F.F. Chladni's Traité d'Acoustique, using Chladni's 1802 Die Akustik for reference and clarification. Chladni's experiments and observations with sound and vibrations profoundly influenced the development of the field of Acoustics. The famous Chladni diagrams along with other observations are contained in Die Akustik, published in German in 1802 and Traité d'Acoustique, a greatly expanded version, published in French in 1809. The present translation was undertaken by Robert T. Beyer, (...) PhD (1920-2008), noted acoustician, Professor of Physics at Brown University, and Gold Medal recipient of the Acoustical Society of America. Along with many other projects completed over the course of his career, Dr. Beyer translated Von Neumann's seminal work, Mathematical Foundations of Quantum Mechanics from the original German, spent 30 years translating Russian physics treatises and journals, served as editor of the English translation of the Soviet Journal of Experimental and Theoretical Physics, and also authored Sounds of our Times: Two Hundred Years of Acoustics. Represents the first comprehensive English translation of a seminal work in acoustics Translated by a prominent acoustician, and former Gold Medal recipient of the Acoustical Society of America In addition to the classic experiments with glass plates and violin bows, covers topics in music, architecture, and anatomy of human and animal hearing Appeals to a wide audience in physics, acoustics, and history of science. (shrink)

For over thirty years, Stephen Braude has studied the paranormal in everyday life, from extrasensory perception and psychokinesis to mediumship and materialization. _The Gold Leaf Lady and Other Parapsychological Investigations_ is a highly readable and often amusing account of his most memorable encounters with such phenomena. Here Braude recounts in fascinating detail five particular cases—some that challenge our most fundamental scientific beliefs and others that expose our own credulousness. Braude begins with a south Florida woman who can make thin gold-colored (...) foil appear spontaneously on her skin. He then travels to New York and California to test psychokinetic superstars—and frauds—like Joe Nuzum, who claim to move objects using only their minds. Along the way, Braude also investigates the startling allegations of K.R., a policeman in Annapolis who believes he can transfer images from photographs onto other objects—including his own body—and Ted Serios, a deceased Chicago elevator operator who could make a variety of different images appear on Polaroid film. Ultimately, Braude considers his wife’s surprisingly fruitful experiments with astrology, which she has used to guide professional soccer teams to the top of their leagues, as well as his own personal experiences with synchronicity—a phenomenon, he argues, that may need to be explained in terms of a refined, extensive, and dramatic form of psychokinesis. Heady, provocative, and brimming with eye-opening details and suggestions, _The Gold Leaf Lady and Other Parapsychological Investigations_ will intrigue both adherents and detractors of its controversial subject matter alike. (shrink)

What is a natural kind? As we shall see, the concept of a natural kind has a long history. Many of the interesting doctrines can be detected in Aristotle, were revived by Locke and Leibniz, and have again become fashionable in recent years. Equally there has been agreement about certain paradigm examples: the kinds oak, stickleback and gold are natural kinds, and the kinds table, nation and banknote are not. Sadly agreement does not extend much further. It is impossible to (...) discover a single consistent doctrine in the literature, and different discussions focus on different doctrines without writers or readers being aware of the fact. In this paper I shall attempt to find a defensible distinction between natural and non-natural kinds. (shrink)

There is a widespread assumption that the classical work in philosophical semantics of Saul Kripke (1980) and Hilary Putnam (1975) has taught us that the essences of natural kinds of substances, such as water and gold, are discoverable only a posteriori by scientific investigation. It is such investigation, thus, that has supposedly revealed to us that it is an essential property of water that it is composed of H2O molecules. This is the way in which Scott Soames, in a recent (...) paper, makes the point in the case of water and H2O: [Here is] how a Kripkean explanation of the necessary a posteriority of [‘Water = H2O’] would go – or at any rate my version of it. The account holds that ‘water’ is a non-descriptive, directly-referential term designating a substance – where substances are taken to be physically constitutive kinds (instances of which share the same basic physical constitution). It is further assumed that a kind of this sort may have different instances in different world-states, and that if a and b are kinds with the same instances in all possible world-states, then a is b. These are clearly metaphysical assumptions, to which we add the natural corollary that for any substance, s, if, in some possible world-state, instances of s have a certain molecular structure, then instances of s have that structure in every world-state. In other words, we assume that it is an essential property of a substance that instances of it have the molecular structure they do. From this it follows that [‘Water = H2O’] is necessary if true, and that ‘H2O’– which I take to be equivalent to ‘the substance instances of which have a molecular structure with two hydrogen atoms and one oxygen atom’– is a rigid designator. Being true, [‘Water = H2O’] is, therefore, necessary. Since knowing the proposition it expresses requires knowing of a certain substance that its instances have a particular chemical structure, [‘Water = H2O’] is knowable only a posteriori. (Soames 2007: 36). (shrink)

‘Water is H2O’ is one of the most frequently cited sentences in analytic philosophy, thanks to the seminal work of Saul Kripke and Hilary Putnam in the 1970s on the semantics of natural kind terms. Both of these philosophers owe an intellectual debt to the empiricist metaphysics of John Locke's Essay Concerning Human Understanding, while disagreeing profoundly with Locke about the reality of natural kinds. Locke employs an intriguing example involving water to support his view that kinds (or ‘species’), such (...) as water and gold, are the workmanship of the human mind. This is the point of his story about a winter visitor to England from Jamaica, who is astonished to find that the water in his basin has turned solid overnight, and proceeds to call it ‘hardened water’. Locke criticizes this judgement, maintaining that it is more consonant with common sense to regard water and ice as different kinds of substance. Putnam, by implication, disagrees. Deploying his imaginary example of Twin Earth—a distant planet where a watery-looking substance, XYZ, rather than H2O, fills the oceans and rivers—he maintains that common sense supports the judgement that XYZ and H2O, despite their superficial similarity, are not the same kind of substance, precisely because their molecular compositions are different. Here it will be argued that both views are mistaken, but that, in this dispute, Locke has more right on his side than his modern opponents do. (shrink)