Accentuate the negative: Locating possibility in Darwin’s ‘long argument’

Charles Darwin’s On the Origin of Species has an unusual format. After presenting his theory of Natural Selection in its first four chapters, there follows a series of five chapters presenting a large number of problems and objections to the theory which, he admits, appear overwhelming. Not until chapter 10 does he begin to present what he takes to be the positive evidence for his theory. In this paper I trace the evolution of this structure from its first hints in his Species Notebooks , through the 1842 Sketch and 1844 Essay to the Origin, showing that it reflects a growing awareness on Darwin’s part of what I call ’In Principle Impossible’ arguments against his theory, and of a systematic strategy for disarming them.     

Novelty,coherence, and Mendeleev’s periodic table

Predictivism is the view that successful predictions of “novel” evidence carry more confirmational weight than accommodations of already known evidence. Novelty, in this context, has traditionally been conceived of as temporal novelty. However temporal predictivism has been criticized for lacking a rationale: why should the time order of theory and evidence matter? Instead, it has been proposed, novelty should be construed in terms of use-novelty, according to which evidence is novel if it was not used in the construction of a theory. Only if evidence is use-novel can it fully support the theory entailing it. As I point out in this paper, the writings of the most influential proponent of use-novelty contain a weaker and a stronger version of use-novelty. However both versions, I argue, are problematic. With regard to the appraisal of Mendeleev’ periodic table, the most contentious historical case in the predictivism debate, I argue that temporal predictivism is indeed supported, although in ways not previously appreciated. On the basis of this case, I argue for a form of so-called symptomatic predictivism according to which temporally novel predictions carry more confirmational weight only insofar as they reveal the theory’s presumed coherence of facts as real.     

Holography and emergence

In this paper, I discuss one form of the idea that spacetime and gravity might ‘emerge’ from quantum theory, i.e. via a holographic duality, and in particular via AdS/CFT duality. I begin by giving a survey of the general notion of duality, as well as its connection to emergence. I then review the AdS/CFT duality and proceed to discuss emergence in this context. We will see that it is difficult to find compelling arguments for the emergence of full quantum gravity from gauge theory via AdS/CFT, i.e. for the boundary theory's being metaphysically more fundamental than the bulk theory.     

Is Newton a ‘radical empiricist’ about method?

Recently, some Newton scholars have argued that Newton is an empiricist about metaphysics—that ideally, he wants to let advances in physical theory resolve either some or all metaphysical issues. But while proponents of this interpretation are using ‘metaphysics’ in a very broad sense, to include the ‘principles that enable our knowledge of natural phenomena’, attention has thus far been focused on Newton’s approach to ontological, not epistemological or methodological, issues. In this essay, I therefore consider whether Newton wants to let physical theory bear on the very ‘principles that enable our knowledge’. By examining two kinds of argument in the Principia, I contend that Newton can be considered a methodological empiricist in a substantial respect. I also argue, however, that he cannot be a ‘radical empiricist’—that he does not and cannot convert all methodological issues into empirical issues.     

The case for black hole thermodynamics part II: Statistical mechanics

I present in detail the case for regarding black hole thermodynamics as having a statistical-mechanical explanation in exact parallel with the statistical-mechanical explanation believed to underlie the thermodynamics of other systems. (Here I presume that black holes are indeed thermodynamic systems in the fullest sense; I review the evidence for that conclusion in the prequel to this paper.) I focus on three lines of argument: (i) zero-loop and one-loop calculations in quantum general relativity understood as a quantum field theory, using the path-integral formalism; (ii) calculations in string theory of the leading-order terms, higher-derivative corrections, and quantum corrections, in the black hole entropy formula for extremal and near-extremal black holes; (iii) recovery of the qualitative and (in some cases) quantitative structure of black hole statistical mechanics via the AdS/CFT correspondence. In each case I briefly review the content of, and arguments for, the form of quantum gravity being used (effective field theory; string theory; AdS/CFT) at a (relatively) introductory level: the paper is aimed at readers with some familiarity with thermodynamics, quantum mechanics and general relativity but does not presume advanced knowledge of quantum gravity. My conclusion is that the evidence for black hole statistical mechanics is as solid as we could reasonably expect it to be in the absence of a directly-empirically-verified theory of quantum gravity.     

Inference to the best explanation and Norton's material theory of induction

I argue that we should consider Norton's material theory of induction as consisting of two largely independent claims. First, there is the claim that material facts license inductions - a claim which I interpret as a type of contextualism about induction. Second, there is the claim that there are no universal rules of induction. While a good case can be made for the first claim, I believe that Norton's arguments for the second claim are lacking. In particular, I spell out Norton's argument against the claim that all induction may be reduced to inference to the best explanation, and argue that it is not persuasive. Rejecting this part of Norton's theory does not however require us to abandon the first claim that material facts license inductions. In this way, I distinguish the parts of the material theory of induction we should happily accept from the parts about which we should be more skeptical.     

(Mis)Understanding scientific disagreement: Success versus pursuit-worthiness in theory choice

Scientists often diverge widely when choosing between research programs. This can seem to be rooted in disagreements about which of several theories, competing to address shared questions or phenomena, is currently the most epistemically or explanatorily valuable—i.e. most successful. But many such cases are actually more directly rooted in differing judgments of pursuit-worthiness, concerning which theory will be best down the line, or which addresses the most significant data or questions. Using case studies from 16^th-century astronomy and 20^th-century geology and biology, I argue that divergent theory choice is thus often driven by considerations of scientific process, even where direct epistemic or explanatory evaluation of its final products appears more relevant. Broadly following Kuhn's analysis of theoretical virtues, I suggest that widely shared criteria for pursuit-worthiness function as imprecise, mutually-conflicting values. However, even Kuhn and others sensitive to pragmatic dimensions of theory ‘acceptance’, including the virtue of fruitfulness, still commonly understate the role of pursuit-worthiness—especially by exaggerating the impact of more present-oriented virtues, or failing to stress how ‘competing’ theories excel at addressing different questions or data. This framework clarifies the nature of the choice and competition involved in theory choice, and the role of alternative theoretical virtues.     

Computational models: a modest role for content

The computational theory of mind construes the mind as an information-processor and cognitive capacities as essentially representational capacities. Proponents of the view (hereafter, ‘computationalists’) claim a central role for representational content in computational models of these capacities. In this paper I argue that the standard view of the role of representational content in computational models is mistaken; I argue that representational content is to be understood as a gloss on the computational characterization of a cognitive process.     

Understanding Deutsch's probability in a deterministic multiverse

Difficulties over probability have often been considered fatal to the Everett interpretation of quantum mechanics. Here I argue that the Everettian can have everything she needs from ‘probability’ without recourse to indeterminism, ignorance, primitive identity over time or subjective uncertainty: all she needs is a particular rationality principle.The decision-theoretic approach recently developed by Deutsch and Wallace claims to provide just such a principle. But, according to Wallace, decision theory is itself applicable only if the correct attitude to a future Everettian measurement outcome is subjective uncertainty. I argue that subjective uncertainty is not available to the Everettian, but I offer an alternative: we can justify the Everettian application of decision theory on the basis that an Everettian should care about all her future branches. The probabilities appearing in the decision-theoretic representation theorem can then be interpreted as the degrees to which the rational agent cares about each future branch. This reinterpretation, however, reduces the intuitive plausibility of one of the Deutsch–Wallace axioms (measurement neutrality).     

A similarity-based approach of Kuhn’s no-overlap principle and anomalies

In their book Cognitive Structure of Scientific Revolutions, Hanne Andersen, Peter Barker, and Xiang Chen reconstruct Kuhn’s account of conceptual structure and change, based on the dynamic frame model. I argue against their reconstruction of anomalies and of the no-overlap principle and propose a competing model, based on the similarity relation. First, I introduce the concept of psychological distance between objects, and then I show that the conceptual structure of a theory consists of a set of natural families, separated by a significant empty space. I argue that, in such a conceptual structure, the ES condition, according to which the distance between natural families should be greater than the distance between any two objects belonging to the same natural family, is satisfied. Anomalous objects lead to the violation of this condition. I argue that in a conceptual structure satisfying the ES condition, a similarity relation could be defined, so that natural families would be similarity classes, satisfying the no-overlap principle. In a structure not satisfying this principle, such similarity classes could not be delimited.     

Epigenesis in Kant: Recent reconsiderations

Epigenesis has become a far more exciting issue in Kant studies recently, especially with the publication of Jennifer Mensch's Kant’ Organicism. In my commentary, I propose to clarify my own position on epigenesis relative to that of Mensch and others by once again considering the discourse of epigenesis in the wider eighteenth century. Historically, I maintain that Kant was never fully an epigenesist because he feared its materialist implications. This makes it highly unlikely that he drew heavily, as other interpreters like Dupont and Huneman have suggested, on Caspar Friedrich Wolff for his ultimate theory of “generic preformation.” In order to situate more precisely what Kant made of epigenesis, I distinguish his metaphysical use, as elaborated by Mensch, from his view of it as a theory for life science. In that light, I raise questions about the scope and authority of philosophy vis a vis natural science.     

Is there just one possible world? Contingency vs the bootstrap

As an example of what might be considered a candidate for an interesting and significant development in the methodology of recent science, I examine some of the epistemological and ontological commitments of the bootstrap conjecture of high energy theoretical physics. This conjecture holds that a well defined but infinite set of self-consistency conditions determines uniquely the entities or paticles which can exist. That is, once we are given any partial information about the actually existing world, nothing else about that world is contingent or arbitrarily adjustable. This almost Leibnizian idea is implemented in S-matrix theory through a unitarity equation, which is a statement of conservation of probability. The S-matrix program is contrasted with quantum field theory which does have arbitrarily assignable quantities. In spite of the highly constrained structure of S-matrix theory, that theory makes far fewer ontological and epistemological assumptions than does quantum field theory.     

Drawing the line between kinematics and dynamics in special relativity

Special relativity is preferable to those parts of Lorentz's classical ether theory it replaced because it shows that various phenomena that were given a dynamical explanation in Lorentz's theory are actually kinematical. In his book, Physical Relativity, Harvey Brown challenges this orthodox view. I defend it. The phenomena usually discussed in this context in the philosophical literature are length contraction and time dilation. I consider three other phenomena in the same class, each of which played a role in the early reception of special relativity in the physics literature: the Fresnel drag effect, the velocity dependence of electron mass, and the torques on a moving capacitor in the Trouton–Noble experiment. I offer historical sketches of how Lorentz's dynamical explanations of these phenomena came to be replaced by their now standard kinematical explanations. I then take up the philosophical challenge posed by the work of Harvey Brown and Oliver Pooley and clarify how those kinematical explanations work. In the process, I draw attention to the broader importance of the kinematics–dynamics distinction.     

Realism on the rocks: Novel success and James Hutton's theory of the earth

In this paper, I introduce a new historical case study into the scientific realism debate. During the late-eighteenth century, the Scottish natural philosopher James Hutton made two important successful novel predictions. The first concerned granitic veins intruding from granite masses into strata. The second concerned what geologists now term “angular unconformities”: older sections of strata overlain by younger sections, the two resting at different angles, the former typically more inclined than the latter. These predictions, I argue, are potentially problematic for selective scientific realism in that constituents of Hutton's theory that would not be considered even approximately true today played various roles in generating them. The aim here is not to provide a full philosophical analysis but to introduce the case into the debate by detailing the history and showing why, at least prima facie, it presents a problem for selective realism. First, I explicate Hutton's theory. I then give an account of Hutton's predictions and their confirmations. Next, I explain why these predictions are relevant to the realism debate. Finally, I consider which constituents of Hutton's theory are, according to current beliefs, true (or approximately true), which are not (even approximately) true, and which were responsible for these successes.     

Conventionalism,structuralism and neo-Kantianism in Poincaré׳s philosophy of science

Poincaré is well known for his conventionalism and structuralism. However, the relationship between these two theses and their place in Poincaré׳s epistemology of science remain puzzling. In this paper I show the scope of Poincaré׳s conventionalism and its position in Poincaré׳s hierarchical approach to scientific theories. I argue that for Poincaré scientific knowledge is relational and made possible by synthetic a priori, empirical and conventional elements, which, however, are not chosen arbitrarily. By examining his geometric conventionalism, his hierarchical account of science and defence of continuity in theory change, I argue that Poincaré defends a complex structuralist position based on synthetic a priori and conventional elements, the mind-dependence of which precludes epistemic access to mind-independent structures.     

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.     

Time reversal operations,representations of the Lorentz group,and the direction of time

A theory is usually said to be time reversible if whenever a sequence of states S₁(t₁), S₂(t₂), S₃(t₃) is possible according to that theory, then the reverse sequence of time reversed states S₃^T(t₁), S₂^T(t₂), S₁^T(t₃) is also possible according to that theory; i.e., one normally not only inverts the sequence of states, but also operates on the states with a time reversal operator T. David Albert and Paul Horwich have suggested that one should not allow such time reversal operations T on states. I will argue that time reversal operations on fundamental states should be allowed. I will furthermore argue that the form that time reversal operations take is determined by the type of fundamental geometric quantities that occur in nature and that we have good reason to believe that the fundamental geometric quantities that occur in nature correspond to irreducible representations of the Lorentz transformations. Finally, I will argue that we have good reason to believe that space-time has a temporal orientation.     

Mechanisms,the interventionist theory,and the ability to use causal relationships

In the area of social science, in particular, although we have developed methods for reliably discovering the existence of causal relationships, we are not very good at using these to design effective social policy. Cartwright argues that in order to improve our ability to use causal relationships, it is essential to develop a theory of causation that makes explicit the connections between the nature of causation, our best methods for discovering causal relationships, and the uses to which these are put. I argue that Woodward's interventionist theory of causation is uniquely suited to meet Cartwright's challenge. More specifically, interventionist mechanisms can provide the bridge from ‘hunting causes’ to ‘using them’, if interventionists (i) tell us more about the nature of these mechanisms, and (ii) endorse the claim that it is these mechanisms—or whatever constitutes them—that make causal claims true. I illustrate how having an understanding of interventionist mechanisms can allow us to put causal knowledge to use via a detailed example from organic chemistry.     

Underdetermination and decomposition in Kepler's Astronomia Nova

This paper examines the underdetermination between the Ptolemaic, Copernican, and the Tychonic theories of planetary motions and its attempted resolution by Kepler. I argue that past philosophical analyses of the problem of the planetary motions have not adequately grasped a method through which the underdetermination might have been resolved. This method involves a procedure of what I characterize as decomposition and identification. I show that this procedure is used by Kepler in the first half of the Astronomia Nova, where he ultimately claims to have refuted the Ptolemaic theory, thus partially overcoming the underdetermination. Finally, I compare this method with other views of scientific inference such as bootstrapping.     

The Passions of the soul and Descartes’s machine psychology

Descartes developed an elaborate theory of animal physiology that he used to explain functionally organized, situationally adapted behavior in both human and nonhuman animals. Although he restricted true mentality to the human soul, I argue that he developed a purely mechanistic (or material) ‘psychology’ of sensory, motor, and low-level cognitive functions. In effect, he sought to mechanize the offices of the Aristotelian sensitive soul. He described the basic mechanisms in the Treatise on man, which he summarized in the Discourse. However, the Passions of the soul contains his most ambitious claims for purely material brain processes. These claims arise in abstract discussions of the functions of the passions and in illustrations of those functions. Accordingly, after providing an intellectual context for Descartes’s theory of the passions, especially by comparison with that of Thomas Aquinas, I examine its ‘machine psychology’, including the role of habituation and association. I contend that Descartes put forth what may reasonably be called a ‘psychology’ of the unensouled animal body and, correspondingly, of the human body when the soul does not intervene. He thus conceptually distinguished a mechanistically explicable sensory and motor psychology, common to nonhuman and human animals, from true mentality involving higher cognition and volition and requiring (in his view) an immaterial mind.