Supervenience and (non-modal) reductionism in Leibniz’s philosophy of time

It has recently been suggested that, for Leibniz, temporal facts globally supervene on causal facts, with the result that worlds differing with respect to their causal facts can be indiscernible with respect to their temporal facts. Such an interpretation is at variance with more traditional readings of Leibniz’s causal theory of time, which hold that Leibniz reduces temporal facts to causal facts. In this article, I argue against the global supervenience construal of Leibniz’s philosophy of time. On the view of Leibniz defended here, he adopts a non-modal reduction of time to events, a form of reductionism that entails a strong covariation between a world’s temporal facts and its causal facts. Consequently, worlds discernible with respect to their temporal facts must be discernible with respect to their causal facts, and worlds discernible with respect to their causal facts must be discernible with respect to their temporal facts. This position strongly favors the standard identificatory reduction of time to causation often imputed to Leibniz.     

Popper’s response to Dingle on special relativity and the problem of the observer

Dingle contended that Einstein’s special theory of relativity was physically impossible for the simple reason that it required clocks to be simultaneously faster and slower than each other. McCrea refuted Dingle using an operationalist argument. An operational response did not satisfy Popper, who wrote an unpublished essay to counter Dingle’s claim. Popper developed an analysis that avoided operationalism by using a system of coinciding clocks, contending that this system showed that special relativity withstood Dingle’s criticism that it was not a symmetrical and consistent physical theory. However, Popper mistakenly included an asymmetric calculation in his analysis. Once this is corrected, the amended result supports Dingle’s position. Popper went on to argue that to avoid determinism, special relativity had to be reconciled with absolute time; this too supports Dingle. Popper’s failure to refute Dingle calls into question his claim that ‘the observer’ is superfluous to special relativity.     

Forces and causes in Kant’s early pre-Critical writings

This paper considers Kant’s conception of force and causality in his early pre-Critical writings, arguing that this conception is best understood by way of contrast with his immediate predecessors, such as Christian Wolff, Alexander Baumgarten, Georg Friedrich Meier, Martin Knutzen, and Christian August Crusius, and in terms of the scientific context of natural philosophy at the time. Accordingly, in the True estimation Kant conceives of force in terms of activity rather than in terms of specific effects, such as motion (as unnamed Wolffians had done). Kant’s explicit arguments in the Nova dilucidatio for physical influx (in the guise of the principle of succession) are directed primarily against the conception of grounds and existence held by Wolff, Baumgarten, and Meier, and only secondarily against Leibniz (by asserting the priority of bodies over mind rather than vice versa). Finally, Kant’s reconciliation of the infinite divisibility of space and the unity of monads in the Physical monadology is designed to respond to objections that could be raised naturally by Wolff and Baumgarten.     

Kant’s third law of mechanics: The long shadow of Leibniz

This paper examines the origin, range and meaning of the Principle of Action and Reaction in Kant’s mechanics. On the received view, it is a version of Newton’s Third Law. I argue that Kant meant his principle as foundation for a Leibnizian mechanics. To find a ‘Newtonian’ law of action and reaction, we must look to Kant’s ‘dynamics,’ or theory of matter.     

Revisiting Galison’s ‘Aufbau/Bauhaus’ in light of Neurath’s philosophical projects

In his article entitled ‘Aufbau/Bauhaus’ and related work, Peter Galison explores the connections between the Vienna Circle and the Dessau Bauhaus. Historically, these groups were related, with members of each group familiar with the ideas of the other. Galison argues that their projects are related as well, through shared political views and methodological approach. The two main figures that connect the Vienna Circle to the Bauhaus—and the figures upon which Galison focuses—are Rudolf Carnap and Otto Neurath. Yet, in our view, the connections that Galison develops do not properly capture the common themes between the Bauhaus and Neurath’s philosophical projects. In this paper, we will examine a few of the historical connections between the Dessau Bauhaus and the Vienna Circle, as well as the philosophical connections that Galison draws between these two groups. By examining in greater depth Neurath’s philosophical commitments, we aim to demonstrate that some of these philosophical connections fail to resonate with Neurath’s projects. And, finally, we develop different connections between Neurath’s projects and the Bauhaus. In our view, these new connections between Neurath and the Dessau Bauhaus are both substantive and philosophically interesting.     

The intelligibility of motion and construction: Descartes’ early mathematics and metaphysics, 1619-1637

I argue for an interpretation of the connection between Descartes’ early mathematics and metaphysics that centers on the standard of geometrical intelligibility that characterizes Descartes’ mathematical work during the period 1619 to 1637. This approach remains sensitive to the innovations of Descartes’ system of geometry and, I claim, sheds important light on the relationship between his landmark Geometry (1637) and his first metaphysics of nature, which is presented in Le monde (1633). In particular, I argue that the same standard of clear and distinct motions for construction that allows Descartes to distinguish ‘geometric’ from ‘imaginary’ curves in the domain of mathematics is adopted in Le monde as Descartes details God’s construction of nature. I also show how, on this interpretation, the metaphysics of Le monde can fruitfully be brought to bear on Descartes’ attempted solution to the Pappus problem, which he presents in Book I of the Geometry. My general goal is to show that attention to the standard of intelligibility Descartes invokes in these different areas of inquiry grants us a richer view of the connection between his early mathematics and philosophy than an approach that assumes a common method is what binds his work in these domains together.     

Response to one point in Gingras’s review of Gravity’s shadow

Yves Gingras says of my book Gravity’s shadow that it is too long, the style is poor, and in its 870 pages there is nothing new that is not to be regretted. Gingras’s purity of vision would be a cause for congratulation were it not for the appalling implications of one of his claims. For the sake of the future of social science—indeed for the sake of the future of civilisation—it is impossible to leave unchallenged the idea that respondents, who don’t like to see their use of data questioned, are to be commended when they withhold those data from public scrutiny.     

Weyl’s ‘agens theory’ of matter and the Zurich Fichte

This paper investigates Hermann Weyl’s reception of philosophical concepts stemming from the German Idealist Johann Gottlieb Fichte. In particular, Weyl’s ‘agens theory’ of matter, which he held around 1925, will be looked at. In the extant literature, the—admittedly also important—influence of Husserl on Weyl has mainly been addressed. Thus, apart from investigating some detailed Fichtean inheritances in Weyl’s concepts of causality, chance and continuity, the general difference which Weyl saw between the philosophies of Fichte and Husserl will also be discussed. For Weyl this is above all a difference between an active constructivism and a rather passive phenomenological seeing (Schau). Further, the paper shows in some detail the way Weyl was drawn into a certain reading of Fichte by his Zurich colleague, the philosopher Fritz Medicus. The methodological frame of the paper is that of Konstellationsforschung, a historical and systematic approach which proves to be particularly fruitful when investigating a (broadly speaking) German Idealist context and which allows special attention to be given to the acting subjects within the constellation under investigation. Conversely, Weyl’s agens theory suggests amendments to this methodology.     

Introspection and change in Carnap’s logical behaviourism

In the 1930s, Carnap set out to incorporate psychology into the unity of science, by showing that all cognitively meaningful sentences of psychology can be translated into the language of physics. I will argue that Carnap, relying on his notion of protocol languages, defends a physicalistic philosophy of psychology that shows due appreciation of ‘introspection’ as a strictly subjective, but reliable way to verify sentences about one’s own mind. Second, I will point out that Carnap’s philosophy of psychology not only takes into account overt behaviour, but must comprise neurophysiological processes as well. Last, I will show that Carnap aims to develop a philosophy of psychology that does justice to the ongoing changeability of scientific knowledge.     

Reflections on Kant’s concept (and intuition) of space

In this paper, I investigate an important aspect of Kant’s theory of pure sensible intuition. I argue that, according to Kant, a pure concept of space warrants and constrains intuitions of finite regions of space. That is, an a priori conceptual representation of space provides a governing principle for all spatial construction, which is necessary for mathematical demonstration as Kant understood it.     

The “dynamics” of Leibnizian relationism: Reference frames and force in Leibniz's plenum

This paper explores various metaphysical aspects of Leibniz's concepts of space, motion, and matter, with the intention of demonstrating how the distinctive role of force in Leibnizian physics can be used to develop a theory of relational motion using privileged reference frames. Although numerous problems will remain for a consistent Leibnizian relationist account, the version developed within our investigation will advance the work of previous commentators by more accurately reflecting the specific details of Leibniz's own natural philosophy, especially his handling of the dynamical interactions of plenum bodies.     

Collecting airs and ideas: Priestley’s style of experimental reasoning

It has often been claimed that Priestley was a skilful experimenter who lacked the capacities to analyze his own experiments and bring them to a theoretical closure. In attempts to revise this view some scholars have alluded to Priestley’s ‘synoptic’ powers while others stressed the contextual role of British Enlightenment in understanding his chemical research. A careful analysis of his pneumatic reports, privileging the dynamics of his experimental practice, uncovers significant yet neglected aspects of Priestley’s science. By focusing on his early experimental conduct and writing on nitrous air, I demonstrate how his methodological and rhetorical devices, far from being consequences of compulsive writing or theoretical naïveté, were deeply entwined with his chemical research. I employ the notion of ‘style of experimental reasoning’ (SER)—derived from A. C. Crombie and I. Hacking—to shed light on the intersection at which Priestley’s unique method, literary style, and epistemology converged to generate scientific knowledge. Establishing Priestley’s SER advances a finer understanding of the interactive character of his pneumatic experimentalism, peculiar dimensions of which have evaded both traditional as well as revisionist scholarship, thus infusing the longstanding historiographic debate over his scientific merits.     

The power of images: mathematics and metaphysics in Hobbes's optics

This paper deals with Hobbes's theory of optical images, developed in his optical magnum opus, ‘A Minute or First Draught of the Optiques’ (1646), and published in abridged version in De homine (1658). The paper suggests that Hobbes's theory of vision and images serves him to ground his philosophy of man on his philosophy of body. Furthermore, since this part of Hobbes's work on optics is the most thoroughly geometrical, it reveals a good deal about the role of mathematics in Hobbes's philosophy. The paper points to some difficulties in the thesis of Shapin and Schaffer, who presented geometry as a ‘paradigm’ for Hobbes's natural philosophy. It will be argued here that Hobbes's application of geometry to optics was dictated by his metaphysical and epistemological principles, not by a blind belief in the power of geometry. Geometry supported causal explanation, and assisted reason in making sense of appearances by helping the philosopher understand the relationships between the world outside us and the images it produces in us. Finally the paper broadly suggests how Hobbes's theory of images may have triggered, by negative example, the flourishing of geometrical optics in Restoration England.     

The uses and abuses of ‘consensus’ forecasts

Clemen's (1989) review of the forecast-combining literature amply illustrates both the interest in and the importance of this subject. This article stresses the tautological properties of various consensus measures that assure their success relative to most individual forecasts. It confirms the finding of earlier studies that for each specific macroeconomic variable roughly one-third of individual forecasters are more accurate than a consensus. However, each individual does relatively poorly for some variable while the consensus, in contrast, necessarily never fails relative to most individuals. These results, like most previous studies, describe consensus measures that are synthetic constructs derived from a pre-existing set of individual forecasts. Strictly speaking, this contemporaneous consensus is not available to individual forecasters when their forecasts are made. A prior consensus measure, which is in their information sets, was relatively much less accurate than the contemporaneous measure. Nevertheless, a small subset of individual forecasters were generally inferior to the known, prior consensus forecast.     

Endogenous synthesis of peptidoglycan in eukaryotic cells; a novel concept involving its essential role in cell division, tumor formation and the biological clock.

Degradation products of peptidoglycan, the universal bacterial cell wall constituent, were previously found in animal tissues and urine. Reassessment and quantitative analysis of available data lead to an original concept, i.e. that eukaryotic cells synthesize peptidoglycan. We present a model in which this endogenously synthesized peptidoglycan is essential for the processes of eukaryotic cell division and sleep induction in animals. Genes for peptidoglycan metabolism, like those for lysine biosynthesis in plants, are probably inherited from endosymbiotic bacteria, the ancestors of mitochondria and chloroplasts. Corollaries of this concept, i.e. roles for peptidoglycan metabolism in tumor formation and in the biological clock, are supported by abundant evidence. We propose that many interactions between bacteria and eukaryotes are conditioned by their common genetic heritage.     

The TSH receptor and its role in thyroid disease

The thyrotropin (TSH) receptor plays a preeminent role in thyroid physiology and disease. TSH, acting through the TSH receptor, is the major stimulator of thyroid cell growth, differentiation and function. In Graves' disease, the TSH receptor is the target of stimulating antibodies that cause hyperthyroidism. Although still a topic of debate, the TSH receptor has been implicated in the pathogenesis of the endocrine ophthalmopathy associated with Graves' disease. Blocking antibodies against the TSH receptor are involved in the development of hypothyroidism in a subset of patients with autoimmune hypothyroidism. Transplacental passage of stimulating or blocking TSH receptor antibodies from a mother with autoimmune thyroid disease may result in transient hyper- or hypothyroidism in early infancy. During pregnancy, the placental hormone human choriogonadotropin (hCG) can cause gestational hyperthyroidism through cross-reaction with the TSH receptor. Gestational hyperthyroidism may also be involved in the pathogenesis of hyperemesis gravidarum. Trophoblast tumors secreting hCG are a rare cause of hyperthyroidism. Somatic activating mutations of the TSH receptor have been identified as a molecular cause of toxic adenomas, whereas activating mutations in the germline give rise to nonautoimmune familial hyperthyroidism or sporadic congenital hyperthyroidism. These gain-of-function mutations are dominant, and one mutated allele is sufficient to result in disease. Inactivating germline mutations of both TSH receptor alleles lead to variable degrees of resistance to TSH, encompassing a spectrum ranging from euthyroid hyperthyrotropinemia to overt hypothyroidism with thyroid hypoplasia. Received 31 January 2001; received after revision 3 April 2001; accepted 3 April 2001     

Duhem’s theory of mixture in the light of the Stoic challenge to the Aristotelian conception

The bulk of Duhem’s writing which bears on the understanding of mixtures suggests he adopted an Aristotelian position which he opposed only to the atomic view. A third view from antiquity—that of the Stoics—seems not to be taken into account. But his lines of thought are not always as explicit as could be wished. The Stoic view is considered here from a perspective which Duhem might well have adopted. This provides a background against which his somewhat unorthodox Aristotelianism might be understood.