I apply James Woodward’s interventionist theory of causation to organic chemistry, modelling three different ways that chemists are able to manipulate the reaction conditions in order to control the outcome of a reaction. These consist in manipulations to the reaction kinetics, thermodynamics, and whether the kinetics or thermodynamics predominates. It is possible to construct interventionist causal models of all of these kinds of manipulation, and therefore to account for them using Woodward’s theory. However, I show that there is an alternate, (...) more illuminating way of thinking about the third kind of reaction control, according to which chemists are thought of as manipulating which causal system is instantiated. I show that our ability to manipulate which system is instantiated is an important part of our ability to control the world, as is therefore especially relevant to interventionism. Thus, considering examples from organic chemistry leads to the identification of an important extension to Woodward’s theory. Finally, this investigation into reaction control in organic chemistry also has a more general implication: it suggests that interventionism results in a version of pragmatism about causation. (shrink)

Travelling waves crossing the nervous networks at mesoscopic/macroscopic scales have been correlated with different brain functions, from long-term memory to visual stimuli. Here we investigate a feasible relationship between wave generation/propagation in recurrent nervous networks and a physical/chemical model, namely the Belousov–Zhabotinsky reaction. Since BZ’s nonlinear, chaotic chemical process generates concentric/intersecting waves that closely resemble the diffusive nonlinear/chaotic oscillatory patterns crossing the nervous tissue, we aimed to investigate whether wave propagation of brain oscillations could be described in terms (...) of BZ features. We compared experimentally detected oscillations during the spontaneous activity of the brain with BZ-like concentric waves simulated by a recently introduced artificial network. The observed overlap and agreement between simulated and measured oscillatory patterns suggests that changes in cortical areas’ neural activity might be described in terms of a recognizable diffusion pattern. We describe biological plausibility, benefits and limits of our approach and discuss the relationship among BZ-like networks, Pandemonium-like architectures and the spontaneous activity of the brain. ER -. (shrink)

In contrast to the conventional homogeneous kinetics, there is no conception of a simple reaction in the solid-state reaction kinetics. The geometric-probabilistic phenomenology currently in use is not adequate for describing the interplay between the chemical mechanism and the observed kinetic behaviour. An attempt is made to formulate a conception of simple reaction in the solid state as a basis for constructing kinetic models of involved reactions.

In his celebrated historic-epistemological work Identité et réalité, Émile Meyerson claimed that the scientific conservation principles were first suggested and accepted for philosophical reasons, and only afterwards were submitted to experimental tests. One of the instances he discussed in his book is the principle of mass conservation in chemical reactions. Meyerson pointed out that several authors, from Antiquity to Kant, accepted the idea of quantitative conservation of matter; and Lavoisier himself was strongly influenced by a priori ideas, using (...) this principle instead of attempting to test it. This paper will review Meyerson’s claim and historic evidence, focusing especially the late nineteenth and early twentieth century, when the principle of mass conservation was tested in highly accurate experiments. Instead of confirming the principle, some of those experiments led to the detection of anomalies. Hans Landolt, for instance, noticed that there were some small violations of the principle. He observed mass variations of about 10−6 in chemical reactions produced in hermetically sealed glass tubes. Since Landolt was a famous chemist, his results produced a strong response. Several researchers repeated his experiments, with different results. Landolt himself improved his experiments, with a balance that could detect mass changes of 10−7. After changes of the experimental procedure, the chemical reactions did not show significant mass changes. There was not, however, any “crucial experiment” “proving” that mass was conserved. The observed anomalies were set aside mainly by theoretical reasons, after the discovery of radioactivity and the development of the theory of relativity. (shrink)

The project of chemistry to classify substances and develop techniques for their transformation into other substances rests on assumptions about the means by which compounds are constituted and reconstituted. Robert Boyle not only proposed empirical tests for a metaphysics of material corpuscules, but also a principle for designing experimental procedures in line with that metaphysics. Later chemists added activity concepts to the repertoire. The logic of activity explanations in modern times involves hierarchies of activity concepts, transitions between levels through non-dispositional (...) groundings. Such hierarchies terminate in powerful particulars, such as elementary charged particles. Do these have a fundamental place in the most recent accounts of molecular architecture, stabilities and transformations? However, a close study of the contemporary chemistry of substances transforming reactions discloses a hybrid metaphysics, making use of both the Boylean corpuscles and Faradayan fields. This is illustrated by an analysis of the metaphysics inherent in John Polanyi’s use of “chemoluminescence” to follow the formation of products in chemical reactions. A brief sketch of a resolution of the tension between the two metaphysical schemes is drawn from Niels Bohr’s radical metaphysics extended from the quantum realm proper to chemistry (and perhaps beyond). (shrink)

The concept of extent of reaction was discussed many times in physical chemistry journals and books. This contribution strongly suggests the use of the extent of reaction as standard basic tool in teaching stoichiometry. The same idea was suggested several times in the past without success because the concept of extent of reaction is still not presented in the first-year general chemistry textbooks. It is also remarked that the concept of extent of reaction represents a simple example of the way (...) of attaining a mathematization of chemistry, that is chemistry thought and made with the mathematical way of thinking, i.e. using variables, symbols and functions. Presenting the concept of the extent of reaction within the general chemistry curriculum will support successive physical chemistry courses, as these courses make extensive use of this powerful concept when teaching thermodynamics and kinetics of chemical reactions. (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)

There are inherent difficulties in a subject like chemistry particularly the notion of a chemical reaction. In this paper the difficulties are discussed from a teaching and learning perspective and from a history of chemistry perspective. Three teaching/learning studies of the incompleteness of the iron thiocyanate reaction in chemical equilibrium are reviewed and it is shown that a recent historical study of the iron thiocyanate reaction has the potential to challenge the interpretation of the incompleteness of the reaction. (...) This establishes a controversial context where students can be introduced to epistemic thinking, that is, how to interrogate chemistry data and form a conclusion which resonates with what we know about the nature of science. A curriculum suggestion for pre-service chemistry teachers is provided. (shrink)

ABSTRACT Between 1920 and 1922, the University of Bristol biochemist, Maximilian Nierenstein, published four papers in a series exploring the structure of catechin in the Journal of the Chemical Society. The Society then abruptly refused to accept any more of his papers on catechin, or any other subject. It provided him with no reasons for the embargo until 1925. It then transpired that Nierenstein was boycotted because it was deemed that he had not responded adequately to criticisms of his (...) work made by his rival in catechin research, the German natural products chemist, Karl Freudenberg. It was not until 1929 that, as a result of a petition by a group of his former Bristol pupils and friends, that Nierenstein was again permitted to publish in the Society’s journal. The paper explores the Chemical Society’s treatment of Nierenstein in detail, sheds new light on his career and his reaction to the Society’s unprecedented boycott, examines some of the structural chemistry involved in the disputes, and discusses whether Nierenstein’s research deserves the label of ‘bad science’. (shrink)

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)

Prokaryotes growing at high temperatures have a high proportion of charged residues in their proteins to stabilize their 3D structure. By mining 175 disparate bacterial and archaeal proteomes we found that, against the general trend for charged residues, the frequency of aspartic acid residues decreases strongly as natural growth temperature increases. In search of the explanation, we hypothesized that the reason for such unusual correlation is the deleterious consequences of spontaneous chemical transformations of aspartate at high temperatures. Our subsequent (...) statistical analysis supported this hypothesis. This finding reveals that organisms have likely adapted to high temperatures by minimizing the harmful consequences of spontaneous chemical transformations. (shrink)

Kant conceives of chemical dissolutions as involving the infinite division and subsequent blending of solvent and solute. In the resulting continuous solution, every subvolume contains a uniform proportion of each reactant. Erich Adickes argues that this account stands in tension with other aspects of Kant’s Critical philosophy and his views on infinity. I argue that although careful analysis of Kant’s conception of dissolution addresses Adickes’ objections, the infinite division inherent to the process is beyond our human cognition, for Kant. (...) Nevertheless, such infinite division may be considered as an idea of reason to make comprehensible chemical reactions, revealing reason to play a pivotal role in the foundations of chemistry. (shrink)

This book examines the way in which Robert Boyle seeks to accommodate his complex chemical philosophy within the framework of a mechanistic theory of matter. More specifically, the book proposes that Boyle regards chemical qualities as properties that emerged from the mechanistic structure of chymical atoms. Within Boyle’s chemical ontology, chymical atoms are structured concretions of particles that Boyle regards as chemically elementary entities, that is, as chemical wholes that resist experimental analysis. Although this interpretation of (...) Boyle’s chemical philosophy has already been suggested by other Boyle scholars, the present book provides a sustained philosophical argument to demonstrate that, for Boyle, chemical properties are dispositional, relational, emergent, and supervenient properties. This argument is strengthened by a detailed mereological analysis of Boylean chymical atoms that establishes the kind of theory of wholes and parts that is most consistent with an emergentist conception of chemical properties. The emergentist position that is being attributed to Boyle supports his view that chemical reactions resist direct explanation in terms of the mechanistic properties of fundamental particles, as well as his position regarding the scientific autonomy of chymistry from mechanics and physics. (shrink)

In this essay, the first statistical and stochastic treatments of chemical dynamics are analyzed and discussed, in particular the diffusive description of chemical reactions. The first part of the paper introduces the historical and methodological basis of the theories about stochastic processes and diffusion as well as their lesser-known applications in chemical kinetics, which were advanced by Jens Anton Christiansen (1888–1969). In the second, part we will focus our attention on the early works of Oskar Benjamin (...) Klein (1894–1977) and Hendrik Anton Kramers (1894–1952) on electrolytes and the latter’s more mature work, which completes and gives a firm theoretical background to Christiansen’s description. (shrink)

Patterns resulting from the sole interplay between reaction and diffusion are probably involved in certain stages of morphogenesis in biological systems, as initially proposed by Alan Turing. Self-organization phenomena of this type can only develop in nonlinear systems (i.e. involving positive and negative feedback loops) maintained far from equilibrium. We present Turing patterns experimentally observed in a chemical system. An oscillating chemical reaction, the CIMA reaction, is operated in an open spatial reactor designed in order to obtain a (...) pure reaction-diffusion system. The two types of Turing patterns observed, hexagonal arrays of spots and parallel stripes, are characterized by an intrinsic wavelength. We identify the origin of the necessary difference of diffusivity between activator and inhibitor. We also describe a pattern growth mechanism by spot splitting that recalls cell division. (shrink)

This chapter contains sections titled: Toxic Chemicals in the Arctic Stratospheric Ozone Loss and Global Warming References and Further Reading.

In these five chapters we introduce, with significant details, the core fundamental notions of (1) deformability, (2) sound and hearing, (3) permeability and porosity, (4) viscosity, (5) immiscibility, (6) wettability, (7) gravity and geodesy, and (8) heat and thermodynamics. We then illustrate, with applications across disciplines, the importance of these notions in our lives and in understanding the world around us. These applications include the description of skyquakes and limnic eruptions, the origin of hydrocarbon accumulations underground, the description of the (...) interiors of our Moon and of Jupiter's core, the differences between near- and far-side of our Moon, vortices in oceans, gravity anomalies of Antarctica and Mars, lateral and vertical plate motions, the absence of induced earthquakes in the Bakken shale play, self-cleaning surfaces including oil spills, human thermoregulation, thermal diagnostics and therapies, bone and muscles losses during space travels, and nuclear fusion by gravitational confinement. (shrink)

The ArgumentThe overall portrayal of early modern experimentation as a new method of securing assent within a philosophical discourse sketched in many of the recent studies on the historical origin of experimentation is questioned by the analysis of the experimental practice of chemistry at the Paris Academy. Chemical experimentation at the Paris Academy in the late seventeenth and early eighteenth century originated in a different tradition than the philosophical. It continued and developed the material culture of the chemical (...) work shops of the sixteenth and seventeenth centuries, and explored epistemic objects which had rather loose connections to philosophy. On the other hand, I argue against the classical dichotomy between the work of the mind that of the hand, and for an epistemology of experimentation that acknowledges that experimental manipulation goes hand in hand with reflexion. In particuler, I argue against the view that chemists at the Paris Academy were “pragmatists” who merely gathered experimental facts and classified substances and operations without perplexing themselves over general conceptions. I claim that the chemists at the Paris Academy constructed a general conception framework which shaped the significance of their experiments. This conception that I call conception of the chemical combination, compound and reaction was rather quickly reified into an experimental fact. Despite its generality it was a genuine chemical conception rather independent of philosophy. (shrink)

Panenmentalist possibilities are individual pure possibilities existing independently of any mind, actual reality, and possible-world conception. These possibilities are a priori accessible to our intellect and imagination. In this paper, I attempt to shed some panenmentalist light on the discovery of chemical branched chain reactions and its implications on biology and cancer research. I also examine the case of the Belousov–Zhabotinsky reaction which, at first, was believed to be impossible. Finally, I proceed to examine through a panenmentalist lens (...) Szilard’s discovery of the possibility of physical chain reactions and Mullis’s discovery of a polymerase chain reaction. All these major actual discoveries clearly depend on the discovery of the relevant panenmentalist possibilities and the ways in which they relate to one another. (shrink)

Summary The purpose of this work is to translate some of Robert Boyle's chemical experiments into the terms of modern chemistry. Most of the reactions involve sensible qualities, since there are on it considerable helpful tracking descriptions like heating, hissing, colour changing, etc. For a long time in the history of science, this procedure was seen as an exercise in anachronism which should be avoided at all costs. Recently many scholars have demonstrated that chemical translation can assist (...) with historical work instead of causing confusion, and it may be very useful as a tool for the history of chemistry and for reproducing past chemical experiments. (shrink)

Philosophers have long debated ‘substrate’ and ‘bundle’ theories as to how properties hold together in objects ― but have neglected to consider that every chemical entity is defined by closure of relationships among components ― here designated ‘Closure Louis de Broglie.’ That type of closure underlies the coherence of spectroscopic and chemical properties of chemical substances, and is importantly implicated in the stability and definition of entities of many other types, including those usually involved in philosophic discourse (...) ― such as roses, statues, and tennis balls. Characteristics of composites are often presumed to ‘supervene on’ properties of components. This assumption does not apply when cooperative interactions among components are significant. Once correlations dominate, then adequate descriptions must involve different entities and relationships than those that are involved in ‘fundamental-level’ description of similar but uncorrelated systems. That is to say, descriptions must involve different semantics than would be appropriate if cooperative interactions were insignificant. This is termed ‘Closure Henri Poincaré. Networks of chemical reactions that have certain types of closure of processes display properties that make other more-complex coherences possible. This is termed ‘Closure Jacques Cauvin.’ Each of these three modes of closure provides a sufficient basis for warranted recognition of causal interaction, thus each of them has epistemological significance. Other modes of epistemologically-important closure probably exist. It is important to recognize that causal efficacy generally depends on closure of relationships of constituents. (shrink)

In the characterization of the ArCl2 'van der Waals complex', a recognizable pattern of well-defined peaks is observed in the microwave absorption spectrum. In the control of chaos in a chemical oscillatory reaction the power spectrum progressively becomes simpler, at length yielding a single peak. Since both of these cases generate coherences that are centers of agency, they should be considered to produce new chemical entities. Applicability of this ontological approach to coherences of wider societal interest is suggested.

SummaryThe convening of the first three Solvay Chemistry Conferences in Brussels from 1922–1928 marked an important turning point for the discipline of chemistry. Whereas much of nineteenth-century chemical endeavour had focused on compositional and functional analysis of chemical compounds, many leaders in chemistry were turning to questions of molecular dynamics by the early twentieth century. Two competing schools of chemical dynamics, which were represented at the Solvay Conferences, were a predominantly English group (Lowry, Lapworth, Robinson, Ingold) who (...) worked out electron and ionic interpretations of organic reaction mechanisms, and a French group (Perrin, Job) who developed a generalized radiation hypothesis of reaction activation. While differences in conceptual and stylistic approach separated the two schools, they agreed on the need to apply contemporary physical theory to old chemical problems, and to develop a theoretical chemistry complementary to theoretical physics. (shrink)

We argue for an account of chemical reactivities as chancy propensities, in accordance with the ‘complex nexus of chance’ defended by one of us in the past (Suárez, 2017, 2020). Reactivities are typically quantified as proportions, and an expression such as “A + B → C” does not entail that under the right conditions some amounts of A and B react to give the amount of C that theoretically would correspond to the stoichiometry of the reaction. Instead, what is (...) produced is a fraction α < 1 of this theoretical amount, and the corresponding percentage is usually known as the yield, which expresses the relative preponderance of its reaction. This is then routinely tested in a laboratory against the observed actual yields for the different reactions. Thus, on our account, reactivities ambiguously refer to three quantities at once. They first refer to the underlying propensities effectively acting in the reaction mechanisms, and which in ‘chemical chemistry’ (Schummer, 1998) are commonly represented by means of Lewis structures. Besides, reactivities represent the probabilities that these propensities give rise to, for any amount of the reactants to combine as prescribed. This last notion is hence best understood as a single case chance and corresponds to a theoretical stoichiometric yield. Finally, reactivities represent the actual yields observed in experimental runs, which account for and provide the requisite evidence for / against both the mechanisms and single case chances ascribed. (shrink)

When “general physiology” emerged as a basic field of research within biology in the early nineteenth century, Henri Ducrotay de Blainville (1777–1850) on the one hand and Johannes Peter Müller (1801–1858) on the other appealed to chemical analysis to account for the properties and operations of organisms that were observed to differ from what was found in inorganic compounds. Their aim was to establish laws of vital organization that would be based on organic chemical processes, but would also (...) be of use to explain morphological and functional differences among life forms. The intent of this paper is to specify for each of these leading physiologists the different presuppositions that provided theoretical frameworks for their interpretation of what they conceived of as laws of organization underpinning the dynamics of vital phenomena. Blainville presumed that the properties of organic compounds depended on the chemical properties of their constitutive molecules, but combined according to patterns of functional development, and that the latter could only be inferred from an empirical survey of modes of organization across the spectrum of life forms. For Müller, while all vital processes involved chemical reactions, in the formative and functional operations of organisms, these reactions would result from the action of life forces that were responsible for the production of organic combinations and thus for vital and animal functions. As both physiologists set significant methodological patterns for their many disciples and followers, their respective quasi-reductionist and anti-reductionist positions need to be accounted for. (shrink)

This paper outlines a phenomenological approach for describing physiological reactions occurring immediately after vital threats. This exemplified by data taken from previous studies relative to chemical intoxications of rats by a neurotoxical drug. The survival rate of the animals and the variations of their cerebral acetylcholinesterese activity are both reported as a function of the drug concentration, and with respect to their age. The collecting of the results may be described as the cusp, a bifurcation set of Thom's (...) Catastrophe Theory.The young animals react by a vital burst which modifies the shape of the cusp. A new fold or pocket takes place, changing it to the butterfly bifurcation set. This pocket supports the survival attractor concept, which appears reactional, transitory and variable in its intensity. (shrink)

A novel non-classical mereological concept built up by blending the Metaphysics of Xavier Zubiri and the Quantum Theory of Atoms in Molecules of R. F. W. Bader is proposed. It is argued that this philosophical concept is necessary to properly account for what happens in a chemical reaction. From the topology of the gradient of the laplacian of the electronic charge density, \\) within the QTAIM framework, different “atomic graphs” are found for each atom depending on the molecular context, (...) reflecting how the whole molecule affects each atom. In this way, the whole molecular system imposes certain geometry onto each atom, and every atom exhibits different ontological modality. On the Metaphysical side, for X. Zubiri real things are system of different notes. The physical essence is the subsystem of essential notes with a coherence unity. Every note is grounded on the essence. The unity of the system is present somehow in every note-of beforehand, and every essential note-of turns towards the other. The essence determines the position of each note within the system, and hence is the grounding for modality of the notes. By conflating both “theories” and taking the atoms as essential notes, we propose the concept of “Molecule in atoms-of” or “atoms-of in Molecules”. Within the course of a chemical reaction the atoms-of modified their “of” as required by the new molecular unity being formed, and eventually change their modality. The validity to the Zubiri’s statements, is attained by evaluating necessity and possibility in a set-up of finite accessible “possible worlds”. (shrink)

Reaction-diffusion systems which have reaction term satisfying f(-q) = -f(q) tend strongly to form striped patterns. Haken’s slaving principle is used to derive differential equations for unstable mode amplitudes close to the Turing instability. This connects a dynamical symmetry to pattern selection, with possible relevance to biological and chemical pattern-forming phenomena.

Is chemistry primarily about things or about processes, about chemical substances or about chemical reactions? Is a chemical reaction defined by the change of certain substances, or are substances defined by their characteristic chemical reactions? What appears to be a play on words to the modern scientist, is actually one of the most fundamental ontological question since antiquity, prompted by the most radical change – the chemical change or the ‘coming-to-be and passing-away’ as (...) Aristotle’s treatise on theoretical chemistry came to be known. The question has bothered philosophers ever since, who were not satisfied with the much too simplistic answer of atomism, according to which the basic elements of nature are atoms. (shrink)

The paper is aimed at defining reduction, oxidation, and redox reactions based both on the oxidation number and charge changes in reacting species. It is rationalized that the processes of oxidation and reduction, usually occurring simultaneously, can occur also as independent processes. It is explained that in balancing chemical equations of redox reactions the “gain” or “loss” of electrons should be understood as changes in oxidation number. A formal expressions “+n e−” and “−n e−” represent in reality (...) a decrease and increase in oxidation number by n units, respectively. (shrink)

This work utilizes examples from chemical sciences to present fundamentals of dialectics and synergetics. The laws of dialectics remain appropriate at the level of atoms, at the level of molecules, at the level of the reactions, and at the level of ideas. The law of the unity and conflict of opposites is seen, for instance, in the relationships between the ionization energy and electron affinity of atoms, between the forward and back reactions, as well as in the (...) differentiation and integration between the various areas of chemistry. The law of the passage of quantitative changes into qualitative changes describes the transformation properties of the compounds when the number and arrangement of atoms in the molecule undergoes changes. According to this law, the development is accompanied by breaks and jumps. This paper suggests equations for the description of these relationships. The law of the negation of the negation is manifested in the Periodic Law, in the evolution of ideas about the mutual transformation of chemical elements, in the development the concept of triads of elements, etc. Small changes in the conventional Periodic Table on the basis of previously rejected versions allow reflecting secondary and additional periodicity. Synergetics, similarly to dialectics, is dedicated to the studies of general laws of evolution. Synergetics includes highly advanced and specified ideas of dialectics. The cornerstone of synergetics is the principles of self-organization and nonlinearity. Mathematical development of these concepts was substantially facilitated by considering oscillating chemical reactions as an example. These reactions are quite complex and therefore provide adequate models for self-organization. Oscillations may exist only upon execution of specific thermodynamic, mathematical, and chemical conditions. Mechanisms of several oscillatory reactions are briefly reviewed. The construction of novel biomimetic or smart materials based on oscillating reactions is described. (shrink)

We present a novel approach to represent ecological systems using reaction networks, and show how a particular framework called chemical organization theory sheds new light on the longstanding complexity–stability debate. Namely, COT provides a novel conceptual landscape plenty of analytic tools to explore the interplay between structure and stability of ecological systems. Given a large set of species and their interactions, COT identifies, in a computationally feasible way, each and every sub-collection of species that is closed and self-maintaining. These (...) sub-collections, called organizations, correspond to the groups of species that can survive together in the long-term. Thus, the set of organizations contains all the stable regimes that can possibly happen in the dynamics of the ecological system. From here, we propose to conceive the notion of stability from the properties of the organizations, and thus apply the vast knowledge on the stability of reaction networks to the complexity–stability debate. As an example of the potential of COT to introduce new mathematical tools, we show that the set of organizations can be equipped with suitable joint and meet operators, and that for certain ecological systems the organizational structure is a non-boolean lattice, providing in this way an unexpected connection between logico-algebraic structures, popular in the foundations of quantum theory, and ecology. (shrink)

We present a novel approach to represent ecological systems using reaction networks, and show how a particular framework called chemical organization theory sheds new light on the longstanding complexity–stability debate. Namely, COT provides a novel conceptual landscape plenty of analytic tools to explore the interplay between structure and stability of ecological systems. Given a large set of species and their interactions, COT identifies, in a computationally feasible way, each and every sub-collection of species that is closed and self-maintaining. These (...) sub-collections, called organizations, correspond to the groups of species that can survive together in the long-term. Thus, the set of organizations contains all the stable regimes that can possibly happen in the dynamics of the ecological system. From here, we propose to conceive the notion of stability from the properties of the organizations, and thus apply the vast knowledge on the stability of reaction networks to the complexity–stability debate. As an example of the potential of COT to introduce new mathematical tools, we show that the set of organizations can be equipped with suitable joint and meet operators, and that for certain ecological systems the organizational structure is a non-boolean lattice, providing in this way an unexpected connection between logico-algebraic structures, popular in the foundations of quantum theory, and ecology. (shrink)

Henry Eyring's absolute rate theory explains the size of chemical reaction rate constants in terms of thermodynamics, statistical mechanics, and quantum chemistry. In addition it uses a number of unique concepts such as the 'transition state'. A key feature of the theory is that the explanation it provides relies on the comparison of reaction rate constant expressions derived from these individual theories. In this paper, the example is used to develop a naturalized notion of reduction and the unity of (...) science. This characterization provides the necessary clues to the sort of inter-theoretic linkages that are present in the theory of reaction rates. The overall theory is then further characterized as a theory network, establishing connections between non-reductive notions of inter-theory connections. This characterization also sheds new light on the unity of science. (shrink)

This paper considers the nature of a curriculum as presented in formal curriculum documents, and the inherent difficulties of representing formal disciplinary knowledge in a prescription for teaching and learning. The general points are illustrated by examining aspects of a specific example, taken from the chemistry subject content included in the science programmes of study that are part of the National Curriculum in England. In particular, it is suggested that some statements in the official curriculum document are problematic if we (...) expect a curriculum to represent canonical disciplinary knowledge in an unambiguous and authentic manner. The paper examines the example of the requirement for English school children to be taught that chemical reactions take place in only three different ways and considers how this might be interpreted in terms of canonical chemistry and within the wider context of other curriculum statements, in order to make sense of neutralisation and precipitation reactions. It is argued that although target knowledge that is set out as the focus of teaching and learning cannot be identical to disciplinary knowledge, the English National Curriculum offers a representation of chemistry which distorts and confuses canonical ideas. It is suggested that the process of representing the disciplinary knowledge of chemistry as curriculum specifications is worthy of more scholarly attention. (shrink)