Michela Massimi has written a book broad in scope and ambition but full of wonderful details. It moves from technical philosophical discussions of conditionals to detailed case studies of work in child literacy. From perspectival art to dark matter. From Borges to blown glass – and much else in between. It is impossible not to be impressed. -/- Massimi's book is a detailed elaboration and defence of a position, perspectival realism, she has been developing over several years. Perspectival realism offers (...) a new twist on realism debates in science. Standard scientific realist views focus on the products of science. They are concerned with questions like whether our current scientific theories are approximately true or our best models accurate. Massimi's perspectival realism, in contrast, focuses on the process of scientific investigation. She is interested in the question of how scientific communities come to produce reliable knowledge. Massimi addresses that question by offering the reader several detailed case studies. The centrepiece of the book is a long and multi-part discussion in Chapter 4 in which she describes the development of models in nuclear physics, climate science, and developmental psychology. The central message of each case study is the same: scientific knowledge emerges through the interaction of diverse scientific communities. For example, crucial to the development of models explaining nuclear stability was prior work done by petrologists, vulcanologists, meteorologists, and others in establishing a consistent pattern of isotopic abundances through a variety of environments. It was this knowledge which in conjunction with other accepted physical constraints, like Pauli's exclusion principle, that led to the development of a series of nuclear models, culminating in Goeppert Mayer and Jensen's Nobel Prize-winning shell model. (shrink)

Mechanisms occurring at the atomic level are now known to drive processes essential for life, as revealed by quantum effects on biochemical reactions. Some macroscopic characteristics of organisms may thus show an atomic imprint, which may be transferred across organisms and affect their evolution. This possibility is considered here for the first time, with the aim of elucidating the appearance of an animal innovation with an unclear evolutionary origin: migratory behaviour. This trait may be mediated by a radical pair (RP) (...) mechanism in the retinal flavoprotein cryptochrome, providing essential magnetic orientation for migration. Isotopes may affect the performance of quantum processes through their nuclear spin. Here, we consider a simple model and then apply the standard open quantum system approach to the spin dynamics of cryptochrome RP. We changed the spin quantum number (I) and g‐factor of hydrogen and nitrogen isotopes to investigate their effect on RP's yield and magnetic sensitivity. Strong differences arose between isotopes with I = 1 and I = 1/2 in their contribution to cryptochrome magnetic sensitivity, particularly regarding Earth's magnetic field strengths (25–65 µT). In most cases, isotopic substitution improved RP's magnetic sensitivity. Migratory behaviour may thus have been favoured in animals with certain isotopic compositions of cryptochrome. (shrink)

The mechanistic significance of a kinetic isotope effect on a cytochrome P‐450catalyzed reaction depends, fundamentally, on the nature of the interaction of the substrate with the active site of the enzyme as well as on the nature of the chemistry of the reaction catalyzed. Consequently, kinetic isotope effects can be used to extract information on the topology of the enzyme and the mechanism of substrate oxidation. Kinetic isotope effect studies are sometimes accompanied by ‘metabolic switching’ or a change in metabolic (...) pathway, catalyzed either by the same enzyme or by a different enzyme. For the specific case where ‘metabolic switching’ gives rise to a change in regional specificity for the cytochrome P‐450 catalyzed metabolism of a compound, this change can be explained in terms of the topological constraints on substrate binding imposed by the active site of the enzyme. (shrink)

Stable heavy isotopes co‐exist with their lighter counterparts in all elements commonly found in biology. These heavy isotopes represent a low natural abundance in isotopic composition but impose great retardation effects in chemical reactions because of kinetic isotopic effects (KIEs). Previous isotope analyses have recorded pervasive enrichment or depletion of heavy isotopes in various organisms, strongly supporting the capability of biological systems to distinguish different isotopes. This capability has recently been found to lead to general decline of heavy (...) isotopes in metabolites during yeast aging. Conversely, supplementing heavy isotopes in growth medium promotes longevity. Whether this observation prevails in other organisms is not known, but it potentially bears promise in promoting human longevity. (shrink)

The precise position of a spectral line emitted by an atomic system depends on the mass of the atomic nucleus and is therefore different for isotopes belonging to the same element. The possible presence of an isotope effect followed from Bohr's atomic theory of 1913, but it took several years before it was confirmed experimentally. Its early history involves the childhood not only of the quantum atom, but also of the concept of isotopy. Bohr's prediction of the isotope effect was (...) apparently at odds with early attempts to distinguish between isotopes by means of their optical spectra. However, in 1920 the effect was discovered in HCl molecules, which gave rise to a fruitful development in molecular spectroscopy. The first detection of an atomic isotope effect was no less important, as it was by this means that the heavy hydrogen isotope deuterium was discovered in 1932. The early development of isotope spectroscopy led to successes as well as problems. At the end of the paper I briefly comment on the relationship between theory, experiment and prediction in this area of spectral physics. (shrink)

A sample from the Ubatuba fragment collected in Brazil in 1957 was tested with the intent of examining the isotope ratios of its primary element, magnesium, and the trace elements strontium, barium, copper, and zinc. As background, the history of chemical testing of the Ubatuba fragments during the 1960s-1980s at multiple labs with varying capabilities is reviewed and then the remainder of the paper examines recent tests completed in 2017 and 2018 that for the first time used HR-ICPMS techniques to (...) look at the isotopic ratios of the minor constituents as well as the primary magnesium makeup of the sample. The magnesium isotope ratios were found to fall within terrestrial limits while the results on the isotope ratios of the trace elements was inconclusive. Recommendations are made for improving the process of examining the trace elements. Keywords: Ubatuba, isotope, magnesium, HR-ICPMS, UFO. (shrink)

Several authors have investigated the question of whether canonical logic-based accounts of belief revision, and especially the theory of AGM revision operators, are compatible with the dynamics of Bayesian conditioning. Here we show that Leitgeb's stability rule for acceptance, which has been offered as a possible solution to the Lottery paradox, allows to bridge AGM revision and Bayesian update: using the stability rule, we prove that AGM revision operators emerge from Bayesian conditioning by an application of the principle (...) of maximum entropy. In situations of information loss, or whenever the agent relies on a qualitative description of her information state - such as a plausibility ranking over hypotheses, or a belief set - the dynamics of AGM belief revision are compatible with Bayesian conditioning; indeed, through the maximum entropy principle, conditioning naturally generated AGM revision operators. This mitigates an impossibility theorem of Lin and Kelly for tracking Bayesian conditioning with AGM revision, and suggests an approach to the compatibility problem that highlights the information loss incurred by acceptance rules in passing from probabilistic to qualitative representations of beliefs. (shrink)

Despite great advances in recent scholarship on the political philosophy of John Rawls, Rawls’s conception of stability is not fully appreciated. This essay aims to remedy this by articulating a more complete understanding of stability and its role in Rawls’s theory of justice. I argue that even in A Theory of Justice Rawls maintains that within liberal democratic constitutionalism judgments of relative stability typically adjudicate decisively among conceptions of justice and is committed to more deeply than to (...) the substantive content of justice as fairness. This essay thus emphasizes the continuity of Rawls’s thought over time and motivates the position that Rawlsian stability is as philosophically significant and distinctively Rawlsian as justice as fairness itself. (shrink)

Here I present and discuss a model that, among other things, appears able to describe the dynamics of cancer cell origin from the perspective of stable and unstable gene expression profiles. In identifying suchaberrantgene expression profiles as lying outside the normal stable states attracted through development and normal cell differentiation, the hypothesis explains why cancer cells accumulate mutations, to which they are not robust, and why these mutations create a new stable state far from the normal gene expression profile space. (...) Such cells are in strong contrast with normal cell types that appeared as an attractor state in the gene expression dynamical system under cell‐cell interaction and achieved robustness to noise through evolution, which in turn also conferred robustness to mutation. In complex gene regulation networks, otheraberrantcellular states lacking such high robustness are expected to remain, which would correspond to cancer cells. (shrink)

In this paper I discuss the relation between various properties that have been regarded as important for determining whether or not a belief constitutes a piece of knowledge: its stability, strength and sensitivity to truth, as well as the strength of the epistemic position in which the subject is with respect to this belief. Attempts to explicate the relevant concepts more formally with the help of systems of spheres of possible worlds (à la Lewis and Grove) must take care (...) to keep apart the very different roles that systems of spheres can play. Nozicks sensitivity account turns out to be closer to the stability analysis of knowledge (versions of which I identify in Plato, Descartes, Klein and Lehrer) than one might have suspected. (shrink)

This paper supports the literature which argues that derivational robustness can have epistemic import in highly idealized economic models. The defense is based on a particular example from mathematical economic theory, the dynamic Walrasian general equilibrium model. It is argued that derivational robustness first increased and later decreased the credibility of the Walrasian model. The example demonstrates that derivational robustness correctly describes the practices of a particular group of influential economic theorists and provides support for the arguments of philosophers who (...) have offered a general epistemic justification of such practices. (shrink)

Cognitive Science, Volume 45, Issue 11, November 2021.

Grossberg and VanDieren have started a program to develop a stability theory for tame classes. We name some variants of tameness and prove the following. Let K be an AEC with Löwenheim-Skolem number ≤κ. Assume that K satisfies the amalgamation property and is κ-weakly tame and Galois-stable in κ. Then K is Galois-stable in κ⁺ⁿ for all n<ω. With one further hypothesis we get a very strong conclusion in the countable case. Let K be an AEC satisfying the amalgamation (...) property and with Löwenheim-Skolem number ℵ₀ that is ω-local and ℵ₀-tame. If K is ℵ₀-Galois-stable then K is Galois-stable in all cardinalities. (shrink)

The concept of contextual emergence is proposed as a non-reductive, yet welldefined relation between different levels of description of physical and other systems. It is illustrated for the transition from statistical mechanics to thermodynamical properties such as temperature. Stability conditions are crucial for a rigorous implementation of contingent contexts that are required to understand temperature as an emergent property. It is proposed that such stability conditions are meaningful for contextual emergence beyond physics as well.

I challenge Gareth Eaton’s recent claim that Theodore Richards should be counted among the discoverers of isotopes. In evaluating Eaton’s claim, I draw on two influential theories of scientific discovery, one developed by Thomas Kuhn, and one developed by Augustine Brannigan. I argue that though Richards’ experimental work contributed to the discovery, his work does not warrant attributing the discovery to him. Richards’ reluctance to acknowledge isotopes is well documented. Further, the fact that he made no claim to having made (...) the discovery also undermines Eaton’s argument. (shrink)

Will a synthesis of developmental and evolutionary biology require a focus on the role of nongenetic resources in evolution? Nongenetic variation may exist but be hidden because the phenotypes are stable (developmentally canalized) under certain background conditions. In this case, those differences may come to play important roles in evolution when background conditions change. If this is so, then a focus on the way that developmental resources are made reliable, and the ways in which reliability fails, may prove to be (...) of crucial importance to linking developmental and evolutionary biology. †To contact the author, please write to: 208 Hovland Hall, Philosophy Department, Oregon State University, Corvallis, OR 97331‐3902; e‐mail: [email protected]. (shrink)

Much recent work on explanation in the interventionist tradition emphasizes the explanatory value of stable causal generalizations—i.e., causal generalizations that remain true in a wide range of background circumstances. We argue that two separate explanatory virtues are lumped together under the heading of `stability’. We call these two virtues breadth and guidance respectively. In our view, these two virtues are importantly distinct, but this fact is neglected or at least under-appreciated in the literature on stability. We argue that (...) an adequate theory of explanatory goodness should recognize breadth and guidance as distinct virtues, as breadth and guidance track different ideals of explanation, satisfy different cognitive and pragmatic ends, and play different theoretical roles in helping us understand the explanatory value of mechanisms. Thus keeping track of the distinction between these two forms of stability yields a more accurate and perspicuous picture of the role that stability considerations play in explanation. (shrink)

This book develops a general analysis and synthesis framework for impulsive and hybrid dynamical systems.

Louis Loeb has argued that Hume is pessimistic while Peirce is optimistic about the attainment of fully stable beliefs. In contrast, we argue that Hume was optimistic about such attainment but only if the scope of philosophical investigation is limited to first-order explanatory questions. Further, we argue that Peirce, after reformulating the pragmatic maxim to accommodate the reality of counterfactuals, was pessimistic about such attainment. Finally, we articulate and respond to Peirce's objection that Hume's skeptical arguments in T 1.4.1 and (...) his commitment to common sense indicate that Hume was confused about whether we could have stable beliefs at all. (shrink)

In Stability and Justification in Hume’s Treatise, Louis Loeb ascribes to Hume a naturalistic account of justified belief, one on which Hume is fundamentally concerned with the question whether stable belief can be achieved. Loeb’s interpretation is systematic, richly explanatory, and powerfully argued. He makes a compelling case that stability plays a central role in Hume’s epistemology. Loeb’s case is so compelling indeed that anyone who wants to defend an alternative interpretation will now have to assimilate or deflect (...) the massive textual evidence in favor of the stability interpretation. I will argue here that, for some passages Loeb cites in favor of the stability interpretation, a veritistic interpretation explains the text at least as well as the stability interpretation does. (shrink)

The replicator dynamics and Moran process are the main deterministic and stochastic models of evolutionary game theory. The models are connected by a mean-field relationship—the former describes the expected behavior of the latter. However, there are conditions under which their predictions diverge. I demonstrate that the divergence between their predictions is a function of standard techniques used in their analysis and of differences in the idealizations involved in each. My analysis reveals problems for stochastic stability analysis in a broad (...) class of games, demonstrates a novel domain of agreement between the dynamics, and indicates a broader moral for evolutionary modeling. (shrink)