Alchemists' illustrations indicated through symbols the processes being attempted; but with Lavoisier's Elements (1789), the place of imagination and symbolic language in chemistry was much reduced. He sought to make chemistry akin to algebra and its illustrations merely careful depictions of apparatus. Although younger contemporaries sought, and found in electrochemistry, a dynamical approach based upon forces rather than weights, they found this very difficult to picture. Nevertheless, by looking at chemical illustrations in the eighty years after Lavoisier's revolutionary book, (...) we can learn about how reactions were carried out, and interpreted, and see that there was scope for aesthetic judgement and imagination. (shrink)

This paper examines the claim of G.W.F. Hegel that chemical thinking-the method of thinking employed in chemistry-marks a significant advance upon meCHANistic thinking-the method of thinking characteristic of physics. This is done in the context of Mancur Olson's theory of collective action and public goods. The analogy between the efficiency of a catalyst in bringing about chemical transformation and the function of leaders in free human society in developing latent groups to provide public goods is explored.

There is a persisting debate about what chemical bonds are and whether they exist. I argue that chemical bonds are real patterns of interactions between subatomic particles. This proposal resolves the problems raised in the context of existing understandings of the chemical bond and provides a novel way to defend the reality of chemical bonds.

From the perspective of successive events, chemical reactions are expressed or thought about, in terms of the cause-effect category. In this work, I will firstly discuss some aspects of causation and interaction in chemistry, argue for the interaction, and propose an alternative or complementary representation scheme called “interaction diagram”, that allows representing chemical reactions through a geometric diagram. The understanding of this diagram facilitates the analysis of reactions in terms of the interaction, or reciprocal action, among the (...) participating entities. Secondly, I will describe the model and provide examples and finally, I will discuss the scope and limitations of the current development status of the model. (shrink)

The main scientific problems of chemical bonding were solved half a century ago, but adequate philosophical understanding of chemical combination is yet to be achieved. Chemists routinely use important terms with more than one meaning. This can lead to misunderstandings. Eliminativists claim that what seems to be a baseball breaking a window is merely the action of “atoms, acting in concert.” They argue that statues, baseballs, and similar macroscopic things “do not exist.” When macroscopic objects like baseballs (...) move, exceedingly large numbers of microscopic components coordinate their activities. Understanding how this happens requires attention to the interactions that link parts into larger units. Eliminativists say that everything that truly exists has causal relationships in addition to those of its components—“nonredundant causality.” This paper holds that if a number of entities interact in such a way that the effect of that collection on test objects is different than it would have been in the absence of the interaction, then identification of that collection as a single composite agent is warranted, for purposes to which that difference is relevant. Ordinary “chemical substances” fulfill this version of the requirement of nonredundant causality. Other sorts of chemical coherences, including chemical dissipative structures, also fulfill that criterion. All these types of coherences qualify as “substances” even though they are not all “chemical substances.”. (shrink)

The main scientific problems of chemical bonding were solved half a century ago, but adequate philosophical understanding of chemical combination is yet to be achieved. Chemists routinely use important terms ("element," "atom," "molecule," "substance") with more than one meaning. This can lead to misunderstandings. Eliminativists claim that what seems to be a baseball breaking a window is merely the action of "atoms, acting in concert." They argue that statues, baseballs, and similar macroscopic things "do not exist." When (...) macroscopic objects like baseballs move, exceedingly large numbers (1025) of microscopic components coordinate their activities. Understanding how this happens requires attention to the interactions that link parts into larger units. Eliminativists say that everything that truly exists has causal relationships in addition to those of its components—"nonredundant causality." This paper holds that if a number of entities interact in such a way that the effect of that collection on test objects is different than it would have been in the absence of the interaction, then identification of that collection as a single composite agent is warranted, for purposes to which that difference is relevant. Ordinary "chemical substances" (both elementary materials such as dihydrogen and compounds such as water) fulfill this version of the requirement of nonredundant causality. Other sorts of chemical coherences, including chemical dissipative structures (e.g., flames), also fulfill that criterion. All these types of coherences qualify as "substances" (as that term is used in philosophy) even though they are not all "chemical substances.". (shrink)

Jacques Monod (1971) argued that certain molecular processes rely critically on the property of chemical arbitrariness, which he claimed allows those processes to “transcend the laws of chemistry”. It seems natural, as some philosophers have done, to interpret this in modal terms: a biological relationship is chemically arbitrary if it is possible, within the constraints of chemical “law”, for that relationship to have been otherwise than it is. But while modality is certainly important for understanding chemical (...) arbitrariness, understanding its biological role also requires an account of the concrete causal-functional features that distinguish arbitrary from non-arbitrary phenomena. In this paper I elaborate on this under-emphasised aspect by offering a general account of these features: arbitrary relations are instantiated by mechanisms that involve molecular adapters, which causally couple two properties or processes which would otherwise be uncorrelated. Additionally, adapters work by acting as intermediate rather than cooperating causes. (shrink)

Since the introduction and widespread adoption of chemical herbicides, “weed management” has become almost synonymous with “herbicide management.” Over-reliance on herbicides and herbicide-resistant crops has given rise to herbicide resistant weeds. Integrated weed management (IWM) identifies three strategies for weed management— biological-cultural, chemical-technological, mechanical-physical—and recommends combining all three to mitigate herbicide resistance. However, adoption of IWM has stalled, and research to understand the adoption of IWM practices has focused on single stakeholder groups, especially farmers. In contrast, decisions about (...) weed management often occur within a social ecosystem where multiple stakeholder groups co-create knowledge and practices. To more holistically investigate perceptions and decision-making related to herbicide resistant weed management, we conducted 23 in-depth interviews in combination with Q methodology with farmers and public-/private-sector agricultural professionals in the state of Georgia (U.S.). Our investigation focused on the management of an increasingly herbicide resistant weed, Palmer amaranth, which enabled broader conversations about agricultural systems, farmer livelihoods, and sustainability. Factor and thematic analyses allowed us to identify and characterize two distinct typologies: one primarily valued agronomic efficiency and relied upon chemical-technological management practices, while the other valued diversifying weed management strategies as the pathway to agronomic and economic success. Typologies diverged substantially in attitudes toward the three weed management strategies, the role of technology, and systems management generally. These two viewpoints have implications for how we understand underlying stakeholder motivations and choices around weed management strategies, both of which are crucial in promoting and supporting farmer use of diverse, ecologically-sound, weed management strategies. (shrink)

Nanotechnology, as with many technologies before it, places a strain on existing legislation and poses a challenge to all administrative agencies tasked with regulating technology-based products. It is easy to see how statutory schemes become outdated, as our ability to understand and affect the world progresses. In this article, we address the regulatory problems that nanotechnology posses for the Food and Drug Administration’s (FDA) classification structure for ‘‘drugs’’ and ‘‘devices.’’ The last major modification to these terms was in 1976, with (...) the enactment of the Medical Device Amendments. There are serious practical differences for a classification as a drug or device in terms of time to market and research. Drugs are classified, primarily, as acting by ‘‘chemical action.’’ We lay out some legal, philosophic, and scientific tools that serve to provide a useful, as well as legally and scientifically faithful, distinction between drugs and devices for the purpose of regulatory classification. These issues we raise are worth the consideration of anyone who is interested in the regulation of nano-products or other novel technologies. (shrink)

The strategic use of disease and poison in warfare has been subject to a longstanding and cross-cultural taboo that condemns the hostile exploitation of poisons and disease as the act of a pariah. In short, biological and chemical weapons are simply not fair game. The normative opprobrium is, however, not fixed, but context dependent and, as a social phenomenon, remains subject to erosion by social (or more specifically, antisocial) actors. The cross cultural understanding that fighting with poisons and (...) disease is reprehensible, that they are taboo, is codified through a web of interconnected measures, principal amongst these are the 1925 Geneva Protocol; the Biological Weapons Convention; and the Chemical Weapons Convention. Whilst these treaties have weathered the storm of international events reasonably well, their continued health is premised on their being ‘tended to’ in the face of contextual changes, particularly facing changes in science and technology, as well as the changed nature and character of conflict. This article looks at the potential for normative erosion of the norm against chemical and biological weapons in the face of these contextual changes and the creeping legitimization of chemical and biological weapons. (shrink)

Medical expertise plays a major role in large-scale welfare arrangements, for example, in private insurance companies. It symbolizes the objectivity and reliability of the procedures of risk selection and legitimates the acceptance and rejection of clients. To understand "reliability" in this context, this article discusses the introduction of chemical urine analysis for life insurance examination between 1880 and 1920. The article argues that reliability of urine analysis is not an intrinsic characteristic of the technology and thus cannot serve as (...) the explanation for the relevance of this technology as a means of risk selection. The construction of a "reliable technology" went hand in hand with the development of a standardized, uniform, and predictable performance of the test and an emergence of specific network—namely, a large-scale, bureaucratic insurance practice in which examination rooms of physicians became connected to the head offices of insurance companies by administrative means. During this process, the balance of power between medical examiners and insurance companies was reversed. Insurance compa nies depended on medicine for risk selection, but physicians increasingly had to act according to the rules set by life insurance companies. (shrink)

SummaryThis essay explains why and how nineteenth-century chemists sought to stabilize the melting and boiling points of organic substances as reliable characteristics of identity and purity and how, by the end of the century, they established these values as ‘Constants of Nature’. Melting and boiling points as characteristic values emerge from this study as products of laboratory standardization, developed by chemists in their struggle to classify, understand and control organic nature. A major argument here concerns the role played by the (...) introduction of organic synthesis in driving these changes. Synthetic organic chemistry vastly increased the number of known organic substances, precipitating the chemical identity crisis of my title. Successful natural product synthesis, moreover, depended on chemists’ ability to demonstrate the absolute identity of synthetic product and natural target – something late nineteenth-century chemists eventually achieved by making reliable, replicable melting and boiling point measurements. In the period before the establishment of national standards laboratories, chemists and scientific glassblowers worked together to standardize melting and boiling points as physical constants, such collaborations highlighting the essential importance of chemical glassware and glassblowing skill in the development of nineteenth-century organic chemistry. (shrink)

This paper presents a numerical study of the reaction A ↔ B in the presence of an intermediate and destabilizing step in its dynamics. After introducing a direct autocatalytic destabilizing process, namely quadratic autocatalysis ) and cubic autocatalysis ), a thermodynamic analysis of the evolution of the reaction in closed and open systems was performed. In addition, the Gibbs free energy, the thermodynamic affinity, and the entropy generation of the overall reaction were evaluated for each of the autocatalytic steps, in (...) order to analyze the behavior of these thermodynamic quantities when the system moved towards equilibrium or towards oscillatory non-equilibrium states. (shrink)

Environmental chemicals accumulate in all human bodies and have the potential to affect the health of men and women, adults, and children. This article advances “precautionary consumption”—the effort to mediate personal exposure to environmental chemicals through vigilant consumption—as a new empirical site for understanding the intersections between maternal embodiment and contemporary motherhood as a consumer project. Using in-depth interviews, I explore how a group of 25 mothers employ precautionary consumption to mediate their children’s exposure to chemicals found in food, (...) consumer products, and the home. Most of the mothers in the study situate their children’s chemical “burdens” within their own bodies and undertake the labor of precautionary consumption as part of a larger and commodity-based motherhood project. In actively expanding the sphere of responsible motherhood to include managing children’s body burdens, these mothers navigate multiple and overlapping contexts that hold women accountable for children’s futures and value the agency of the proactive consumer. Yet, as the sphere of responsible mothering expands, women without financial resources, time, and family stability are pushed to the margins of normative motherhood. (shrink)

Chemical elements are the bricks with which Chemistry is build. Their names had a history, but part of it is forgotten or barely known. In this article the forgotten, no more used, never used, and alternatively used names and symbols of the elements are reviewed, bringing to us some surprises and deeper knowledge about the richness of Chemistry. It should be stressed that chemical elements are important not only for chemists but for all people dealing with science. As (...) in any other aspect of our lives, we tend to better understand something by knowing his history. By knowing them we can have a deeply understanding of how science evolves and how it is influenced by our human aspects. (shrink)

This article states that drugs could be used to produce, if not more intelligent individuals, at least individuals with better cognitive functioning. Cognitive functioning is something that we might strive to produce through education, including of course the more general health education of the community. Enhancements are good if and only if they make people better at doing some of the things they want to do including experiencing the world through all of the senses, assimilating and processing what is experienced, (...) remembering and understanding things better, becoming more competent, and experiencing more. Beneficial neural changes have been reported for such familiar technologies as reading, education, physical exercise, and diet. Smart drugs create irresistible competitive pressures such that once they are used everyone is forced to follow in order to keep up, and this is coercive and corrosive. (shrink)

In this article I sketch G. N. Lewis’s views on chemical bonding and Linus Pauling’s attempt to preserve Lewis’s insights within a quantum‐mechanical theory of the bond. I then set out two broad conceptions of the chemical bond, the structural and the energetic views, which differ on the extent in which they preserve anything like the classical chemical bond in the modern quantum‐mechanical understanding of molecular structure. †To contact the author, please write to: Department of Philosophy, (...) Durham University, 50 Old Elvet, Durham DH1 3HN, UK; e‐mail: [email protected]. (shrink)

In his Kritik der reinen Vernunft, Kant asserts that laws of nature “carry with them an expression of necessity”. There is, however, widespread interpretive disagreement regarding the nature and source of the necessity of empirical laws of natural sciences in Kant's system. It is especially unclear how chemistry—a science without a clear, straightforward connection to the a priori principles of the understanding—could contain such genuine, empirical laws. Existing accounts of the necessity of causal laws unfortunately fail to illuminate the (...) possibility of non-physical laws. In this paper, I develop an alternative, ‘ideational’ account of natural laws, according to which ideas of reason necessitate the laws of some non-physical sciences. Chemical laws, for instance, are grounded on ideas of the elements, and the chemist aims to reduce her phenomena to these elements via experimentation. Although such ideas are beyond the possibility of experience, their postulation is necessary for the achievement of reason's theoretical ends: the unification and explanation of the cognitions of science. (shrink)

Roald Hoffmann and other theorists claim that we ought to use highly idealized chemical models (“qualitative models”) in order to increase our understanding of chemical phenomena, even though other models are available which make more highly accurate predictions. I assess this norm by examining one of the tradeoffs faced by model builders and model users—the tradeoff between precision and generality. After arguing that this tradeoff obtains in many cases, I discuss how the existence of this tradeoff can (...) help us defend Hoffmann's norm for modelling. (shrink)

The ArgumentMost historians of science share the conviction that the incorporation of the corpuscular theory into seventeenth-century chemistry was the beginning of modern chemistry. My thesis in this paper is that modern chemisty started with the concept of the chemicl compound, which emerged at the end of the seventeenth and the beginning of the eighteenth century, without any signifivant influence of the corpuscular theory. Rather the historical reconstruction of the emergence of this concept shows that it resulted from the reflection (...) on the chemical operations in the sixteenth-century metallurgy and seventeenth-century pharmacy. I argue that the reversibility of these operations and their understanding as crafts (metallurgy) or chemical arts (pharmacy) were decisive factors for the emergence of the first ideas about chemical compounds in the seventeenth-century pharmaceutical works written by pharmaceutically trained authors, influenced by the Paracelsian image of nature. There is a direct line of descent from these authors to E.F.Geoffroy (1675–1742), who integrated the first scattered ideas of chemical compound into a general concept comprising chemical artefacts as well as natural bodies. (shrink)

To construct a synthetic cell we need to understand the rules that permit life. A central idea in modern biology is that in addition to the four entities making reality, matter, energy, space and time, a fifth one, information, plays a central role. As a consequence of this central importance of the management of information, the bacterial cell is organised as a Turing machine, where the machine, with its compartments defining an inside and an outside and its metabolism, reads and (...) expresses the genetic program carried by the genome. This highly abstract organisation is implemented using concrete objects and dynamics, and this is at the cost of repeated incompatibilities (frustration), which need to be sorted out by appropriate «patches». After describing the organisation of the genome into the paleome (sustaining and propagating life) and the cenome (permitting life in context), we describe some chemical hurdles that the cell as to cope with, ending with the specific case of the methionine salvage pathway. (shrink)

Exposure of man to chemical agents can occur intentionally, as in the treatment of disease, or inadvertently because the environment contains a wide range of synthetic or naturally occurring chemicals. The alkylating agents are a diverse group of compounds (Fig. 1) and comprise a good example of such xenobiotics, since much is known about their occurrence, and their biological effects include carcinogenicity, mutagenicity, toxicity and teratogenicity.Exposure to potentially carcinogenic alkylating agents such as nitrosamines may occur occupationally, from cigarette smoke, (...) from certain foodstuffs and even endogenously through the ingestion of the appropriate precursor chemicals.1 At the other extreme, the cytotoxic effects of agents such as the chloroethylating nitrosamides or mustards have been exploited in the design of certain antitumour drugs.2 The effectiveness of antitumour agents and the other, mostly adverse, biological effects of alkylating agents have been ascribed to their ability to damage cellular macromolecules, in particular DNA. This review concentrates on investigations carried out over the past two years on the role of DNA damage in carcinogenesis, but we shall see how recent advances in this area of research have also led to a better understanding of the mechanisms of the cytotoxic effects of alkylating antitumour agents. (shrink)

Scientific textbooks are often said to deliver a stereotyped kind of knowledge, which conceals rather than reveals the real making of science. They may, however, alternatively be regarded as of peculiar interest for historians of science. An over-mechanical application of the Kuhnian concepts of ‘scientific revolution’ and ‘normal science’ can lead to the neglect of the internal dynamics of ‘normal science’. Scientific textbooks may provide a better understanding of the process of normalization in science.

By comparing chemistry to art, chemists have recently made claims to the aesthetic value, even beauty, of some of their products. This paper takes these claims seriously and turns them into a systematic investigation of the aesthetics of chemical products. I distinguish three types of chemical products - materials, molecules, and molecular models - and use a wide variety of aesthetic theories suitable for an investigation of the corresponding sorts of objects. These include aesthetics of materials, idealistic aesthetics (...) from Plato to Kant and Schopenhauer, psychological approaches of Ernst Gombrich and Rudolf Arnheim, and semiotic aesthetics of Nelson Goodman and Umberto Eco. Although the investigation does not support recent claims, I point out where aesthetics does and can play an import role in chemistry. Particularly, Eco's approach helps us understand that and how aesthetic experience can be a driving force in chemical research. (shrink)

The following is an essay review of Paul Needham's translation of Pierre Duhem's Lemixte et la combinaison chimique and a numberof other essays. In this review we describe theintent and general features of Le mixte and try to place it in the larger context of Duhem'sprogram for energetics. The long essay (Essay3) opposing Marcellin Berthelot'sthermochemistry is singled out for detailedcommentary, since it gives Duhem's reasons forendorsing Josiah Willard Gibbs's chemicalstatics. We argue that a chemical mechanics ofa Gibbsian sort, defended (...) in Le mixte and otheressays in this volume, was the inspiration for,and basis of, Duhem's energetics. Needham'swelcome translations help an English-languageaudience to better understand the basiccontours of Duhem's important, if ultimatelymisguided, project. We conclude with somecomments on the difficulties in translatingDuhem and on the quality of the translationsNeedham has provided. (shrink)

The concepts of atoms and bonds in molecules which appeared in chemistry during the nineteenth century are unavoidable to explain the structure and the reactivity of the matter at a chemical level of understanding. Although they can be criticized from a strict reductionist point of view, because neither atoms nor bonds are observable in the sense of quantum mechanics, the topological and statistical interpretative approaches of quantum chemistry (quantum theory of atoms in molecules, electron localization function and maximum (...) probability domain) provide consistent definitions which accommodate chemistry and quantum mechanics. (shrink)

In learning chemistry at the entry level, many learners labor under misconceptions about the subject matter that are so fundamental that they are typically never addressed. A fundamental misconception in chemistry appears to arise from an adding of existing phenomenal concepts to newly-acquired chemical concepts, so that beginning learners think of chemical entities as themselves having the very same ‘macro’ properties that we observe through the senses. Those who teach or practice chemistry never acquire these misconceptions because they (...) were able to naturally pick up the nature of the subject to begin with. But as a result, they remain unaware of the foundational assumptions and understanding that they operate with and that many beginning learners persistently lack. Thus, a systematic picture of the workings of chemical theory as they relate to observable phenomena needs to be elucidated so that the attention of chemical educators is drawn to the fundamental understanding of the subject that they already possess and that beginning learners of chemistry lack, so that beginning learners can be given the opportunity to gain an understanding of how chemical explanations are in general related to observable phenomena. The ‘layered’ way in which chemical and physical entities are related to each other within chemical theory can also be clarified in this way. To afford this picture, the philosophical concepts of supervenience and emergence are explained and applied to chemistry, as philosophers of chemistry have already done. The result provides a model for teaching chemistry that, if consistently applied, has the potential to greatly enhance fundamental understanding of the subject matter. (shrink)

This paper traces the principal thematic developments in Aristotle’s conception of chemical substance as they bear on the evolution of the notion into modern times. A line of speculation is indicated about the interpretation of elemental proportions clearly raised by Aristotle’s discussion but not pursued in his extant writings. Apart from its historical interest, Aristotle’s discussion of substance and mixture has been taken up in contemporary systematic philosophy (Fine 1995), where it is treated as at best only relevant to (...) ordinary, everyday views. This approach gains support from the contention that such views have been superseded by the molecular conception of chemical substance developed in 19th century science and extolled by advocates of the Kripke-Putnam conception of microessentialism (Kripke 1980, Putnam 1975). Duhem (1902), who well understood what would now be called the macroscopic theory of thermodynamics and its relevance to chemistry, had a different view, and the present discussion is much influenced by him. Certainly, Aristotle’s view stands in need of modification in the light of the understanding of mixtures provided by Gibbs’ phase rule (Gibbs 1948). But with a certain weakening, a central Aristotelian claim about mixtures still has some bearing. (shrink)

The chapter focusses on the Scottish natural philosophy of the late eighteenth century represented by John Anderson (1726–1796) and John Robison (1739–1805), which is considered a link between Newton’s natural philosophy and nineteenth-century physics in Britain (Kelvin and Maxwell). Anderson and Robison have to be seen in a tradition of Scottish Newtonians established in the seventeenth century by David Gregory and John Keill and specifically shaped in the Mid-eighteenth century through the chemical-physical work of Joseph Black and the common-sense (...) philosophy of Thomas Reid. These latter Newtonians built on Newton’s theory of matter and short-range forces as indicated in Query 31 of his Opticks (Black) but also on his Rules of Reasoning of the second edition of his Principia (Black and Reid) and in this way created the theoretical framework in which Anderson and Robison developed their natural philosophy. In the center of their natural philosophy, which was oriented on experimental investigations, were the manifold open questions of the Baconian sciences of that time - theories of heat, light, electricity, magnetism as well as the understanding of the phlogiston. The chapter thus provides insight into the specific way in which the Newtonian camp participated in early modern natural philosophical speculations about minute particles of matter, fluids, or the propagation of light and heat. (shrink)

Though complex networks have been widely applied in the research of chemistry, there is hardly any introduction about the establishment of networks using chemical bonds. In this paper, we consider chemical elements as a system linked by chemical bonds and create the undirected chemical bond network by abstracting nodes from elements and undirected edges from bonds. Connectivity, heterogeneity, small world and disassortativity of this network show the macro structural rationality of this system. The degree and k-order (...) neighbors of an element, which represent the micro topology of this network, can be used to measure its chemical reactivity and detect how many kinds of compounds it can form. The similarity between two elements is measured by the Jaccard index and the VOS mapping technique, results of which are similar to well-known similarities between elements shown by the periodic table. The establishment and topological analysis of this network provide another way to understand and study elements and bonds, and more chemical properties of elements and bonds can be studied by complex networks. (shrink)

Developments in the application of quantum mechanics to the understanding of the chemical bond are traced with a view to examining the evolving conception of the covalent bond. Beginning with the first quantum mechanical resolution of the apparent paradox in Lewis’s conception of a shared electron pair bond by Heitler and London, the ensuing account takes up the challenge molecular orbital theory seemed to pose to the classical conception of the bond. We will see that the threat of (...) delocalisation can be overstated, although it is questionable whether this should be seen as reinstating the issue of the existence of the chemical bond. More salient are some recent developments in a longstanding discussion of how to understand the causal aspects of the bonding interaction—the nature of the force involved in the covalent link—which are taken up in the latter part of the paper. (shrink)

In this book J. Allan Hobson offers a new understanding of altered states of consciousness based on knowledge of how our brain chemistry is balanced when we are...

Chemosensation and mechanosensation cover an enormous spectrum of processes by which animals use information from the environment to adapt their behavior. For pragmatic reasons, these sensory modalities are commonly investigated independently. Recent advances, however, have revealed numerous situations in which they function together to control animals’ actions. Highlighting examples from diverse vertebrates and invertebrates, we first discuss sensory receptors and neurons that have dual roles in the detection of chemical and mechanical stimuli. Next we present cases where peripheral chemosensory (...) and mechanosensory pathways are discrete but intimately packaged to permit coordinated reception of external cues. Finally, we consider how chemical and mechanical signals converge in central neural circuitry to enable multisensory integration. These insights demonstrate how investigation of the interplay between different sensory modalities is key to a more holistic and realistic understanding of sensory‐guided behaviors. (shrink)

Endocrine-disrupting chemicals have been identified as posing risks to reproductive health and may have intergenerational effects. However, responses to the potential harms they pose frequently rely on medicalised understandings of the body and normative gender identities. This article develops an intersectional feminist framework of intergenerational justice in response to the potential risks posed by endocrine-disrupting chemicals. We examine critiques of endocrine disruptors from feminist, critical disability and queer standpoints, and explore issues of race and class in exposures. We argue that (...) responding to the risks posed by endocrine disruptors such as brominated flame retardants (BFRs) and phthalates requires developing a theory of intergenerational justice that recognises relationality and transcorporeality, and that also recognises harm in terms of suffering, not in terms of difference. (shrink)

The function of metaphor in science has been labeled as decorative, persuasive, heuristic, instrumental, facilitating or obstructing. It has sometimes been regarded as inspiring, provoking, perverting or destroying rational thought. Metaphor’s positive role has been noted by philosophers, historians of chemistry, and science education researchers. It has been hailed as a descriptive and explanatory device that stimulates and shapes concept development. I discuss how metaphor functions in science generally, then refine this idea through an examination metaphor’s role in chemical (...) thinking in three contexts: the history and philosophy of chemistry, laboratory research practice, and chemical education. I aim to show how metaphor is already operative in the chemist’s use of the concept of chemical element and that this understanding characterizes chemical thinking in general. The chapter concludes with a discussion of a specifically chemical understanding of metaphor. (shrink)

Next SectionOne of the indisputable signs of the progress made in organic chemistry over the last two hundred years is the increased ability of chemists to manipulate, control, and design chemical reactions. The technological expertise manifest in contemporary synthetic organic chemistry is, at least in part, due to developments in the theory of organic chemistry. By appealing to a notable chemist's attempts to articulate and codify the heuristics of synthetic design, this paper investigates how understanding theoretical organic chemistry (...) facilitates progress in synthetic organic chemistry. The picture that emerges of how the applications of organic chemistry are grounded in its theory is contrasted with both standard and some more contemporary philosophical accounts of the applications of science. IntroductionTotal Synthesis as Applied ScienceUnderstanding Organic ChemistryThe Heuristics of Synthetic DesignAn Example: LongifoleneConclusion. (shrink)

Heisenberg’s explanation of how two coupled oscillators exchange energy represented a dramatic success for his new matrix mechanics. As matrix mechanics transmuted into wave mechanics, resulting in what Heisenberg himself described as …an extraordinary broadening and enrichment of the formalism of the quantum theory , the term resonance also experienced a corresponding evolution. Heitler and London’s seminal application of wave mechanics to explain the quantum origins of the covalent bond, combined with Pauling’s characterization of the effect, introduced resonance into the (...) chemical lexicon. As the Valence Bond approach gave way to a soon-to-be dominant Molecular Orbital method, our understanding of the term resonance, as it might apply to our understanding the chemical bond, has also changed. (shrink)

This Brief presents an historical investigation into the reaction between ferric ions and thiocyanate ions, which has been viewed in different ways throughout the last two centuries. Historically, the reaction was used in chemical analysis and to highlight the nature of chemical reactions, the laws of chemistry, models and theories of chemistry, chemical nomenclature, mathematics and data analysis, and instrumentation, which are important ingredients of what one might call the nature of chemistry. Using the history of the (...) iron thiocyanate reaction as a basis, the book’s main objective is to explore how chemistry develops its own knowledge base; how it assesses the reliability of that base; and how some important tools of the trade have been brought to bear on a chemical reaction to achieve understanding, a worthwhile goal of any historical investigation. (shrink)

Backgrounds: Transcranial direct current stimulation is a non-invasive brain stimulation technique for the treatment of several psychiatric disorders, e.g., mood disorders and schizophrenia. Therapeutic effects of tDCS are suggested to be produced by bi-directional changes in cortical activities, i.e., increased/decreased cortical excitability via anodal/cathodal stimulation. Although tDCS provides a promising approach for the treatment of psychiatric disorders, its neurobiological mechanisms remain to be explored.Objectives: To review recent findings from neurophysiological, chemical, and brain-network studies, and consider how tDCS ameliorates psychiatric (...) conditions.Findings: Enhancement of excitatory synaptic transmissions through anodal tDCS stimulation is likely to facilitate glutamate transmission and suppress gamma-aminobutyric acid transmission in the cortex. On the other hand, it positively or negatively modulates the activities of dopamine, serotonin, and acetylcholine transmissions in the central nervous system. These neural events by tDCS may change the balance between excitatory and inhibitory inputs. Specifically, multi-session tDCS is thought to promote/regulate information processing efficiency in the cerebral cortical circuit, which induces long-term potentiation by synthesizing various proteins.Conclusions: This review will help understand putative mechanisms underlying the clinical benefits of tDCS from the perspective of neurotransmitters, network dynamics, intracellular events, and related modalities of the brain function. (shrink)

In this commentary to Leal (2013), we argue that the memorization of the names and symbols of the chemical elements is necessary in the study of that topic because this task is the key for the later understanding of the Periodic Table. We can make the memorization task in an enjoyable, but effective way, using some educational games in chemistry class. Some recent puzzles, card games, mnemonics rules or games based on drawings to learn the chemical elements (...) are addressed in this paper. (shrink)

This article examines the chemistry of race at the turn of the nineteenth century. Physicians, philosophers, and intellectuals from Benjamin Rush to Everard Home defined the skin color of Africans as resulting from the changes of the body's humors. Radical physicians like Benjamin Rush believed that he could “cure” African slaves of what he identified as indicative of sickness, their skin color, as they were essentially sick white people in his mind. Overall, the study seeks to explain the medical and (...) chemical understanding of race and the potential for “curing” blackness. Often these cures were linked to balancing and unblocking the fluids. A justification for these ideas comes from cases where people seemed to have spontaneously turned black and experiments where black people were turned white. (shrink)

At the heart of chemistry lies the periodic system of chemical elements. Despite being the cornerstone of modern chemistry, the overall structure of the periodic system has never been fully understood from an atomic physics point of view. Group-theoretical models have been proposed instead, but they suffer from several limitations. Among others, the identification of the correct symmetry group and its decomposition into subgroups has remained a problem to this day. In an effort to deepen our limited understanding (...) of the periodic law, we have extended the traditional Lie algebraic framework to account for the peculiar degeneracy structure of the periodic system. Starting from the four-dimensional hidden symmetry and accidental degeneracy of the hydrogen atom, as first revealed by Fock in 1935, our research has mainly focussed on the way this SO(4) symmetry of the Coulomb potential gets broken in the periodic system as a consequence of the transformation of the hydrogenic (n, l) filling order to the Madelung (n+l, n) order due to electronic repulsions, relativistic effects and spin-orbit couplings. In this PhD dissertation, a new left-step format of the periodic table is first proposed on the basis of the Madelung rule. Following the particle physics tradition, the chemical elements are then considered as various states of some 'atomic matter', which is described by a non-compact spectrum-generating dynamical Lie group. The chemical elements are shown to form a basis for a single infinite-dimensional degeneracy space of the SO(4,2) ⊗ SU(2) group. An explanation for the period doubling is then proposed in terms of a particular symmetry breaking of the SO(4,2) group to the anti de Sitter SO(3,2) group. The Madelung rule is rationalised on the basis of nonlinear Lie algebras which reflect the screening of the Coulomb hole. This opens new perspectives for a symmetry-based understanding of how the periodic law emerges from its quantum mechanical foundations, and holds the future promise of complementing our current phenomenological approach by a direct atomic physics approach. (shrink)

This dissertation reassesses the chemical revolution that occurred in eighteenth-century France from the pharmacists' perspective. I use French pharmacy to place the event in historical context, understanding this revolution as constituted by more than simply a change in theory. The consolidation of a new scientific community of chemists, professing an importantly changed science of chemistry, is elucidated by examining the changing relationship between the communities of pharmacists and chemists across the eighteenth century. This entails an understanding of (...) the chemical revolution that takes into account social and institutional transformations as well as theoretical change, and hence incorporates the reforms brought about during and after the French Revolution. First, I examine the social rise of philosophical chemistry as a scientific pursuit increasingly independent of its practical applications, including pharmacy, and then relate this to the theoretical change brought about by Lavoisier and his oxygenic system of chemistry. Then, I consider the institutional reforms that placed Lavoisier's chemistry in French higher education. ;During the seventeenth century, chemistry was intimately entwined with pharmacy, and chemical manipulations were primarily intended to enhance the medicinal properties of a substance. An independent philosophical chemistry gained ground during the eighteenth century, and this development culminated in the work of Lavoisier who cast pharmacy out of his chemistry altogether. Fourcroy, one of Lavoisier's disciples, brought the new chemistry to the pharmacists in both his textbooks and his legislation. Under Napoleon, Fourcroy instituted a new system of education for pharmacists that placed a premium on formal scientific education. Fourcroy's successors, Vauquelin and Bouillon-Lagrange, taught the new chemistry to the elite pharmacists in the School of Pharmacy in Paris. These pharmacists also developed new analytical techniques that combined the aims of the new chemistry with traditional pharmaceutical extractive practices. The scientific pharmacist was created, who, although a respected member of the community of pharmacists, helped to define the new chemistry precisely by not being a true chemist. (shrink)

Many philosophers attribute extraordinary importance to the idea of natural kinds seemingly intimating that the very possibility of certain kinds of activity are ontologically beholden to the existence of kinds. Specifically, regarding chemistry, Brian Ellis intimated that the success of any plausible metaphysical essentialism depends upon its “reliance on examples from chemistry.” Ellis’s view is representative of a tradition in analytic philosophy that has utilized chemical examples as paradigmatic natural kinds. In this regard, Kripke and Putnam emerge as the (...) architects of an entrenched research program dedicated to the chemical tradition of natural kinds in analytic philosophy. The emergence of a critical body of literature by philosophers of chemistry and others has shattered the complacent reliance upon chemical examples as exemplary kinds. On the basis of this emerging critical literature, I will critically explore the way in which chemical practice and inquiry affects the natural kind debate. So, instead of the pretense that we simply carve nature at its joints, we need to become better grounded in the practice of science, and especially with regard to the debate about natural kinds in chemical practice. Consistent with this orientation, we need to make the practice turn, that is, eradicate the fantasy of logical reconstruction and become involved with the interpretative and historical challenges of understanding the nuances of practice. The point here is quite clear, metaphysical questions regarding natural kind should be imminent to scientific practice. Indeed, any legitimate metaphysics of natural kinds should be appropriately informed and grounded in practice and not operate on the basis of a priori sovereignty. I will insert this critical discussion within the analytical context of the notion of interpretive communities and make the case that philosophers should not assume that appeals to the purity of philosophy can substitute for the complexity and practical orientation of chemical practice. (shrink)

The status of the chemical bond has long been a controversial issue with the increasing distance between quantum chemists’ theoretical understanding of molecular stability and the ideas of experimental chemists. Some aspects of the development of the concept of a hydrogen bond are discussed with a view to assessing its import on the general question.

Although Boyle has been regarded as a champion of the seventeenth century Cartesian mechanical philosophy, I defend the position that Boyle’s views conciliate between a strictly mechanistic conception of fundamental matter and a non-reductionist conception of chemical qualities. In particular, I argue that this conciliation is evident in Boyle’s ontological distinction between fundamental corpuscles endowed with mechanistic properties and higher-level corpuscular concretions endowed with chemical properties. Some of these points have already been acknowledged by contemporary scholars, and I (...) actively engage with their ideas in this paper. However I attempt to contribute to the debate over Boyle’s mechanical philosophy by arguing that Boyle’s writings suggest an emergentist, albeit still mechanistic, notion of chemical properties. I contrast Boyle’s views against those of strict reductionist mechanical philosophers, focusing on the famous debate with Spinoza over the redintegration of niter, and argue that Boyle’s complex chemical ontology provides a more satisfactory understanding of chemical phenomena than is provided by a strictly reductionist and Cartesian mechanical philosophy. (shrink)

As an economic pillar, major resource consumer, and polluter of cities, the chemical industry determines many cities’ transformation, prosperity, and decay. It is thus a major concern for achieving the UN Sustainable Development Goals. In China, which is at the stage of accelerated industrialization that is varied across regions, the chemical industry has gradually retreated from developed cities, such as Beijing and Shanghai, in the eastern region, and has become the inevitable choice for industrialization of less-developed cities, such (...) as Xi’an, Chengdu, and Chongqing, in the western region. This study took the perspectives of chemical industrial sectors and their spatial differences to understand the changing patterns of the chemical industry and its dominant cities. It identified chemical industrial cities, examined their spatial-temporal patterns with respect to their industry scale and structure, and accounted for factors influencing the spatial evolution from coastal areas to inland regions. The results show that large CICs were mainly located in coastal port regions with balanced industrial sectors, while small CICs were mainly distributed in inland areas with abundant oil and coal resources and a single dominant industrial sector. The location factors of ports, markets, and technology play important roles in the eastern region, while resource conditions and foreign direct investment promote the chemical industry’s development in the central, western, and northeastern cities. These findings improve the understanding of CICs’ spatial transformation and shed light on the policy-making of chemical industrial development in China and other developing countries. (shrink)