Paneth’s epistemology of chemical elements in light of Kant’s Opus postumum

Friedrich Paneth’s conception of “chemical element” has functioned as the official definition adopted by the International Union of Pure and Applied Chemistry since 1923. Paneth maintains a distinction between empirical and “transcendental” concepts of element; furthermore, chemical science requires fluctuation between the two. The origin of the empirical-transcendental split is found in Immanuel Kant’s classic Critique of Pure Reason (1781/1787). The present paper examines Paneth’s foundational concept of element in light of Kant’s attempt, late in life, to revoke key distinctions made in his Critique, including that of regulative and constitutive functions of reason. In a section of his Opus postumum devoted to the “Transition from the Metaphysical Foundations of Natural Science to Physics,” Kant bends his philosophical system to address the newly emerging sciences of matter of his time. Specifically, he tried, without success, to develop the transcendental ground for microscale motions of bodies encountered in physical, electrical and chemical processes. Paneth’s discussion of chemical element does not take the Opus postumum into account, which is why it begins with a rejection of Kant’s rejection (in his earlier writings) of chemistry’s status as science. I make the case that Paneth’s definition of element effectively maintains something very like Kant’s critical separation of regulative and constitutive principles, while a advancing the concept of chemical science.     

Linking chemistry with physics: arguments and counterarguments

The many-faced relationship between chemistry and physics is one of the most discussed topics in the philosophy of chemistry. In his recent book Reducing Chemistry to Physics. Limits, Models, Consequences, Hinne Hettema (Reducing chemistry to physics. Limits, models, consequences, Rijksuniversiteit Groningen, Groningen, 2012) conceives this relationship as a reduction link, and devotes his work to defend this position on the basis of a “naturalized” concept of reduction. In the present paper I critically review three kinds of issues stemming from Hettema’s argumentation: philosophical, scientific and methodological.     

Proposed terminology of ‘lato sensu metrology’ for scientific methodology

Currently, there are two international scientific vocabularies devoted to properties: one dealing on quantities and the other one dealing on nominal properties. In this article, I am proposing the two mentioned vocabularies be merged in order to make available most of the basic concepts, terms, and definitions needed in observational and experimental scientific methodology in a single vocabulary. In addition, I propose the provisional use of the term “lato sensu metrology” to describe the new vocabulary.     

Liquid crystal chemistry and poetry

This paper comments on a recent article “Revolutionary poetry and liquid crystal chemistry: Herman Gorter, Ada Prins and the interface between literature and science” by Hub Zwart (Foundations of Chemistry, published online: 10 July 2020), in which the author explores the influence of the liquid crystal research of Ada Prins on the epic poem Pan written by her long-time lover Herman Gorter. The present paper reviews the basic science of liquid crystals and explains the connections between the work of Prins and its influence on the poem. Other examples of the use of “liquid crystal” as a literary device are identified from renaissance poetry, and the uses of the metaphor in these poems are analysed from a scientific perspective. From these examples it is suggested that creative concepts from poetry may contain elements of substance that appear in hitherto unrecognised scientific realities.

     

The ‘Sceptical Chemist’– Fundamental concepts in the history of the scientific process of chemical education

The 17th century was witness to scientific chemistry’s emergence from the odd experiments of alchemy. We cannot ascertain its precise date of birth, we can, however, its precise date of christening: in 1661 “The Sceptical Chymist”, the first classical work in the history of chemistry was published by Robert Boyle. Boyle called his chemistry »sceptical« because he had made up his mind to leave aside all mystical explanations and occult attributes as the holy shrine of ignorance. Since those days concepts and theories have been constantly refined under the eyes of the »sceptical chemist« in dialogue with nature. In terms of methodology and concepts the path of recognition was laid down in advance by a contemporary of R. Boyle. It has led in a spiro-cyclical style right up to the end of the 20th century: the principle of the sciences of the 17th century mutated from “corso/ricorso” of then to the “recycling” of today. This principle is discussed.     

Chemistry and the problem of pluralism in science: an analysis concerning philosophical and scientific disagreements

Chemistry, especially its historical practice, has in the philosophy of science in recent decades attracted more and more attention, influencing the turn from the vision of science as a timeless logic-centred system of statements towards the history- and practice-centred approach. The problem of pluralism in science has become a popular topic in that context. Hasok Chang’s “active normative epistemic pluralism” manifested in his book (2012) Is water H₂O? Evidence, realism and pluralism, pursuing an integrated study of history and philosophy of science, has provoked quite a widespread debate. It provides a good opportunity to discuss the topical philosophical issue of the nature of disagreements. The differences among disagreements in different domains have been pointed out in the disagreement literature. It has been noticed that in mathematics and science consensus is established more clearly than in philosophy where it remains largely unachievable (Kornblith in Disagreement, Oxford University Press, Oxford, pp. 29–52, 2010). However, this conclusion is derived in the context of traditional logic-centred view of science. The aim of this paper is to consider the different nature of disagreements in science and in philosophy in the context of the history- and practice-centred approach. The analysis is focused on the critique of the received view of the Chemical Revolution which played quite a central role in Chang’s becoming a pluralist about science. Unlike Chang, however, a modified Kuhnian paradigm-conception of science and scientific revolutions is defended.     

Quantum effects in semiclassical treatment of molecular reactions

By the use of the known Coulomb wavefunctions, “quantal” Coulomb streamlines are defined for the eikonal of the system. Comparisons of such streamlines with the classical Coulomb trajectories are made. Use of such “quantum” Coulomb streamlines is proposed for reaction systems containing the Coulomb interaction U. The derived equations of motion are of particular use for cases where the residual potential V₁ (V₁ = V ? U) has either no classical forbidden region or has relatively small effects on trajectories.     

Ill‐defined chemical concepts: The problem of quantification

From time to time, ill‐defined concepts leads to never‐ending discussions in the chemical literature. “Is there a quadruple bond in the C₂ molecule? What about the boron–boron triple bond? Can we uniquely define concepts like aromaticity or bond order at all?” With this tutorial review I would like to point out that some of the contemporary publications in chemistry are characterized by a confusion of ideas and concepts, and in part ill definitions. And, that exactly those ill‐defined concepts lead to never ending controversies in the literature. Examples of well‐ and ill‐defined concepts in chemistry are discussed.     

On the “New possibility of chemical bonding”: Anti-resonance phenomena

A chemical bond in the absence of a local minimum in the potential surface has been obtained recently by Pollak, Manz, Meyer and Römelt for the I-HI complex. We associate this “new chemical bond” with Simon's proof that a discrete spectrum can be obtained even for a quantum Hamiltonian for which the volume |(P, q)|P² + V(q) ? El is infinite and therefore an infinite number of classical trajectories lead to dissociation (an “anti-resonance” phenomenon). A simple model Hamiltonian which yields for any given E an infinite number of classical dissociative trajectories and also has a discrete spectrum in quantum mechanics, is presented.     

Theoretical temperature dependence of relaxation rate between widely spaced levels,due to gas or liquid fluctuations

In describing relaxation of a small system whose quantum level spacing ?_μ1, exceeds k_BT, one must treat the heat bath quantally even when it is a “classical” fluid. A simple gas model illustrates this, with possible implications for liquids.     

The terms “tochnost’” and “pravil’nost’” as applied to the results of chemical analysis

In this paper, attention is given to the inadequacy of the Russian translation of the term “accuracy” as “pravil’nost’” in publications of the IUPAC recommendations for the presentation of the results of chemical analysis and vocabularies of analytical terms. The essence of the concepts tochnost’ and pravil’nost’ in Russian measurement terminology is considered in historical context, and the evolution of the concepts accuracy in the terminological standards on analytical chemistry (IUPAC Recommendations), metrology, and statistics is traced. It is demonstrated that the one-to-one correspondence between the terms “accuracy” and “tochnost’” and “trueness” and “pravil’nost’,” respectively, which occurs in the present-day standardized terminologies, should also be followed in analytical chemistry     

“Demonstration” vs. “designation” of measurement competence: the need to link accreditation to metrology

Formal acceptance of the results of chemical laboratories is increasingly organized through a) accreditation of measuring laboratories nationally and b) mutual recognition of accreditation internationally (through formal Multilateral Recognition Agreements, MRAs). However, real comparability of results of measurements is realized by using common (internationally agreed) measurement scales which make these results traceable to this scale, i.e. “traceable” to the same (internationally agreed) value of the unit of that scale. In addition, the criterion against which the evaluation is done, should be “external” to the measurement laboratories which are being evaluated. This is realized in IRMM’s International Measurement Evaluation Programme (IMEP) where evaluation is performed against values which are anchored using “metrology”, the science of measurement with its own rules, which offers a sound foundation for measurement in all scientific disciplines. It is argued in this paper that the demonstration of measurement capability against values on such scales provides a result-oriented rather than a procedure-oriented evaluation. Thus, competence can be “demonstrated” rather than just “designated” and this can be shown to both customers and regulators. It inspires more confidence.     

Induced crystallization of poly(ethylene terephthalate) on small metallic nucleating particles

The induction period for the onset of crystallization was determined in poly(ethylene terephthalate) in the presence and absence of small metallic particles. Two kinds of substrates were used: single microcrystals “transplanted” from the water-soluble inorganic polymer (NaPO₃)_x and powders of the same metals (Au, Pt, and Ir). The nucleating activity ? of the substrates was determined on the basis of classical nucleation theory. Values of ? obtained for PET are compared with the corresponding values in the (NaPO₃)_x melt and with theoretical concepts.     

Structure and molecular motion of poly(ethylene oxide) chains adsorbed on a silica-tethered poly(methyl methacrylate) by the spin label method

The spin-label method was used to study the structure and molecular motion of poly(ethylene oxide) (PEO) chains adsorbed on a silica-tethered poly(methyl methacrylate) (PMMA). Spin-labelled PEO with a narrow molecular weight distribution, having number averaged molecular weight (M _N)=6.0×10³, was adsorbed on the surface of the silica-tethered PMMA with various grafting ratios in carbon tetrachloride solution at 35?°C. ESR spectra were measured at various temperatures after the samples were completely dried. The ESR spectra are composed of two spectra arising from spin-labels attached to “train” and “tail” segments, which are strongly and weakly interacted with the silica surface, respectively. The fractional amount of the “tail” segments increases extremely with the grafting ratio of PMMA. Molecular mobility of the PEO chains estimated from the temperature dependence of the ESR spectra also decreases significantly with the grafting ratio of PMMA. Structure and molecular motion of the PMMA chains tethered on the silica were also studied using the spin-labelled PMMA. Consequently, parts of the PEO segments penetrate into the PMMA chains and is adsorbed on the silica surface (“train” segments), whereas parts of the PMMA segments protrude from the surface. The other PEO segments are entangled with the tethered PMMA chains (“tail” segments).     

A MASSive Laboratory Tour. An Interactive Mass Spectrometry Outreach Activity for Children

It is imperative to fascinate young children at an early stage in their education for the analytical sciences. The exposure of the public to mass spectrometry presently increases rapidly through the common media. Outreach activities can take advantage of this exposure and employ mass spectrometry as an exquisite example of an analytical science in which children can be fascinated. The presented teaching modules introduce children to mass spectrometry and give them the opportunity to experience a modern research laboratory. The modules are highly adaptable and can be applied to young children from the age of 6 to 14 y. In an interactive tour, the students explore three major scientific concepts related to mass spectrometry; the building blocks of matter, charged particle manipulation by electrostatic fields, and analyte identification by mass analysis. Also, the students carry out a mass spectrometry experiment and learn to interpret the resulting mass spectra. The multistage, inquiry-based tour contains flexible methods, which teach the students current-day research techniques and possible applications to real research topics. Besides the scientific concepts, laboratory safety and hygiene are stressed and the students are enthused for the analytical sciences by participating in “hands-on” work. The presented modules have repeatedly been successfully employed during laboratory open days. They are also found to be extremely suitable for (early) high school science classes during laboratory visit-focused field trips.

Biomedical applications of X-ray absorption and vibrational spectroscopic microscopies in obtaining structural information from complex systems

Protein crystallography and NMR spectroscopy took decades to emerge as routine techniques in structural biology. X-ray absorption spectroscopy now has reached a similar stage of maturity for obtaining complementary local structural information around metals in metalloproteins. However, the relatively recent emergence of X-ray and vibrational spectroscopic microprobes that build on these techniques has enabled the structural information obtained from the “mature” techniques on isolated biomolecules to be translated into in situ structural information from inhomogeneous complex systems, such as whole cells and tissues.     

Hydrotropes

The concepts “hydrotrope” and “hydrotropy” are reviewed with a strong focus on the literature from recent years. The action and physical–chemical behavior of hydrotropes are discussed in relation to co-solubilizers and surfactants. A definition of a hydrotrope is formulated, and it is demonstrated that the unique behavior of a hydrotrope, which distinguishes this class of substances from both co-solubilizers and regular surfactants, is that the aggregation is weak without a hydrophobic solute, but there is a pronounced aggregation in the presence of a hydrophobic solute.