Quantum ontology without speculation

Existing proposals concerning the ontology of quantum mechanics (QM) either involve speculation that goes beyond the scientific evidence or abandon realism about large parts of QM. This paper proposes a way out of this dilemma, by showing that QM as it is formulated in standard textbooks allows for a much more substantive ontological commitment than is usually acknowledged. For this purpose, I defend a non-fundamentalist approach to ontology, which is then applied to various aspects of QM. In particular, I will defend realism about spin, which has been viewed as a particularly hard case for the ontology of QM.

A second look at the colors of the dinosaurs

In earlier work, I predicted that we would probably not be able to determine the colors of the dinosaurs. I lost this epistemic bet against science in dramatic fashion when scientists discovered that it is possible to draw inferences about dinosaur coloration based on the microstructure of fossil feathers (Vinther et al., 2008). This paper is an exercise in philosophical error analysis. I examine this episode with two questions in mind. First, does this case lend any support to epistemic optimism about historical science? Second, under what conditions is it rational to make predictions about what questions scientists will or will not be able answer? In reply to the first question, I argue that the recent work on the colors of the dinosaurs matters less to the debate about the epistemology of historical science than it might seem. In reply to the second question, I argue that it is difficult to specify a policy that would rule out the failed bet without also being too conservative.

Unspoken Rules: Resolving Underdetermination With Closure Principles

When people learn normative systems, they do so based on limited evidence. Many of the possible actions that are available to an agent have never been explicitly permitted or prohibited. But people will often need to figure out whether those unspecified actions are permitted or prohibited. How does a learner resolve this incompleteness? The learner might assume if an action-type is not expressly forbidden, then acts of that type are permitted. This closure principle is one of Liberty. Alternatively, the learner might assume that if an action-type is not expressly permitted, then acts of that type are prohibited. This closure principle would be one of Residual Prohibition (Mikhail, 2011). On the basis of principles of pedagogical sampling (e.g., Shafto, Goodman, & Griffiths, ), we predicted that participants would infer the Liberty Principle (LP) when trained on prohibitions, and they would infer the Residual Prohibition Principle when trained on permissions. This is exactly what we found across several experiments. We also found a bias in favor of Liberty insofar as participants trained on both a prohibition and a permission rule tended still to infer the LP. However, we also found that if an action is potentially harmful, this diminishes the tendency to infer the LP.

Rediscovering Einstein's legacy: How Einstein anticipates Kuhn and Feyerabend on the nature of science

Thomas Kuhn and Paul Feyerabend promote incommensurability as a central component of their conflicting accounts of the nature of science. This paper argues that in so doing, they both develop Albert Einstein's views, albeit in different directions. Einstein describes scientific revolutions as conceptual replacements, not mere revisions, endorsing 'Kant-on-wheels' metaphysics in light of 'world change'. Einstein emphasizes underdetermination of theory by evidence, rational disagreement in theory choice, and the non-neutrality of empirical evidence. Einstein even uses the term 'incommensurable' specifically to apply to challenges posed to comparatively evaluating scientific theories in 1949, more than a decade before Kuhn and Feyerabend. This analysis shows how Einstein anticipates substantial components of Kuhn and Feyerabend's views, and suggests that there are strong reasons to suspect that Kuhn and Feyerabend were directly inspired by Einstein's use of the term 'incommensurable', as well as his more general methodological and philosophical reflections.

Why Reichenbach wasn't entirely wrong, and Poincaré was almost right, about geometric conventionalism

The present paper revisits conventionalism about the geometry of classical and relativistic spacetimes. By means of critically examining a recent evaluation of conventionalism, we clarify key themes of, and rectify common misunderstandings about, conventionalism. Reichenbach's variant is demarcated from conventionalism simpliciter, associated primarily with Poincaré. We carefully outline the latter's core tenets-as a selective anti-realist response to a particular form of theory underdetermination. A subsequent double defence of geometric conventionalism is proffered: one line of defence employs (and thereby, to some extent, rehabilitates) a plausible reading of Reichenbach's idea of universal forces; another consists in independent support for conventionalism, unrelated to Reichenbach. Conventionalism, we maintain, remains a live option in contemporary philosophy of spacetime physics, worthy of serious consideration.

The Value of 'Traditionality': The Epistemological and Ethical Significance of Non-western Alternatives in Science

After a brief review of the relationship between science and value, this paper introduces the value of 'traditionality' as a value in the pure and applied sciences. Along with other recognized values, this value can also contribute to formulating hypotheses and determining theories. There are three reasons for legitimizing the internal role of this value in science: first, this value can contribute to scientific progress by presenting more diverse hypotheses; second, the value of external consistency in science entails this value; and third, this value helps to eliminate some of the adverse social and cultural effects of Western science in non-Western societies. 'Traditionality' is an extrinsic epistemic value, according to the first two reasons, and at the same time, is an ethical value, according to the last reason. Also, the ethics of belief is adopted to further confirm the ethical role of this value. Finally, this paper discusses three potential criticisms that can be levelled against this idea and responds to each of them.

Bodies of evidence: The 'Excited Delirium Syndrome' and the epistemology of cause-of-death inquiry

"Excited Delirium Syndrome" (ExDS) is a controversial diagnosis. The supposed syndrome is sometimes considered to be a potential cause of death. However, it has been argued that its sole purpose is to cover up excessive police violence because it is mainly used to explain deaths of individuals in custody. In this paper, we examine the epistemic conditions giving rise to the controversial diagnosis by discussing the relation between causal hypotheses, evidence, and data in forensic medicine. We argue that the practitioners' social context affects causal inquiry through background assumptions that enter inquiry at multiple stages. This analysis serves to better understand the wide usage of the controversial diagnosis of ExDS.

Careful with those scissors, Eugene! Against the observational indistinguishability of spacetimes

We discuss Manchak (2009a)'s result that there are locally (but not globally) isometric universes observationally indistinguishable from our own. This theorem makes the epistemic predicament of modern cosmology particularly problematic and the prospects of ever gaining knowledge of the global structure of the universe rather unlikely in the context of general relativity. We argue however that this conclusion is too quick; indeed, Manchak's theorem deploys spacetimes which are not physically reasonable, since they have features which are not the product of any physical process. This ultimately rests on the fact that local isometry between two spacetimes is not sufficient to guarantee that they are both physically reasonable. We propose an additional condition to properly define when a spacetime is physically reasonable, and we show that Manchak's spacetimes do not satisfy this further demand.

Lessons for Theory from Scientific Domains Where Evidence is Sparse or Indirect

In many scientific fields, sparseness and indirectness of empirical evidence pose fundamental challenges to theory development. Theories of the evolution of human cognition provide a guiding example, where the targets of study are evolutionary processes that occurred in the ancestors of present-day humans. In many cases, the evidence is both very sparse and very indirect (e.g., archaeological findings regarding anatomical changes that might be related to the evolution of language capabilities); in other cases, the evidence is less sparse but still very indirect (e.g., data on cultural transmission in groups of contemporary humans and non-human primates). From examples of theoretical and empirical work in this domain, we distill five virtuous practices that scientists could aim to satisfy when evidence is sparse or indirect: (i) making assumptions explicit, (ii) making alternative theories explicit, (iii) pursuing computational and formal modelling, (iv) seeking external consistency with theories of related phenomena, and (v) triangulating across different forms and sources of evidence. Thus, rather than inhibiting theory development, sparseness or indirectness of evidence can catalyze it. To the extent that there are continua of sparseness and indirectness that vary across domains and that the principles identified here always apply to some degree, the solutions and advantages proposed here may generalise to other scientific domains.

Non-epistemic values in shaping the parameters for evaluating the effectiveness of candidate vaccines: the case of an Ebola vaccine trial

This paper examines the case of Ebola, ça Suffit trial which was conducted in Guinea during Ebola Virus Disease (EVD) outbreak in 2015. I demonstrate that various non-epistemic considerations may legitimately influence the criteria for evaluating the efficacy and effectiveness of a candidate vaccine. Such non-epistemic considerations, which are social, ethical, and pragmatic, can be better placed and addressed in scientific research by appealing to non-epistemic values. I consider two significant features any newly developed vaccine should possess; (1) the duration of immunity the vaccine provides; and (2) safety with respect to the side effects of the vaccine. Then, I argue that social and ethical values are relevant and desirable in setting the parameters for evaluating these two features of vaccines. The parameters that are employed for setting up the criteria for assessing the features might have far-reaching implications on the well-being of society in general, and the health conditions of several thousand people in particular. The reason is that these features can play a decisive role during the evaluation of the efficacy and effectiveness of the vaccine. I conclude by showing why it is necessary to reject the concept of epistemic priority, at least when scientists engage in policy-oriented research.

The physics and metaphysics of Tychistic Bohmian Mechanics

The paper takes up Bell's (1987) "Everett (?) theory" and develops it further. The resulting theory is about the system of all particles in the universe, each located in ordinary, 3-dimensional space. This many-particle system as a whole performs random jumps through 3N-dimensional configuration space - hence "Tychistic Bohmian Mechanics" (TBM). The distribution of its spontaneous localisations in configuration space is given by the Born Rule probability measure for the universal wavefunction. Contra Bell, the theory is argued to satisfy the minimal desiderata for a Bohmian theory within the Primitive Ontology framework (for which we offer a metaphysically more perspicuous formulation than is customary). TBM's formalism is that of ordinary Bohmian Mechanics (BM), without the postulate of continuous particle trajectories and their deterministic dynamics. This "rump formalism" receives, however, a different interpretation. We defend TBM as an empirically adequate and coherent quantum theory. Objections voiced by Bell and Maudlin are rebutted. The "for all practical purposes"-classical, Everettian worlds (i.e. quasi-classical histories) exist sequentially in TBM (rather than simultaneously, as in the Everett interpretation). In a temporally coarse-grained sense, they quasi-persist. By contrast, the individual particles themselves cease to persist.

How uncertainty can save measurement from circularity and holism

Measurement results depend upon assumptions, and some of those assumptions are theoretical in character. This paper examines particle physics measurements in which a measurement result depends upon a type of assumption for which that very same result may be evidentially relevant, thus raising a worry about potential circularity in argumentation. We demonstrate how the practice of evaluating measurement uncertainty serves to render any such evidential circularity epistemically benign. Our analysis shows how the evaluation and deployment of uncertainty evaluation constitutes an in practice solution to a particular form of Duhemian underdetermination that improves upon Duhem's vague notion of "good sense," avoids holism, and reconciles theory dependence of measurement with piecemeal hypothesis testing.

Modeling creative abduction Bayesian style

Schurz (Synthese 164:201-234, 2008) proposed a justification of creative abduction on the basis of the Reichenbachian principle of the common cause. In this paper we take up the idea of combining creative abduction with causal principles and model instances of successful creative abduction within a Bayes net framework. We identify necessary conditions for such inferences and investigate their unificatory power. We also sketch several interesting applications of modeling creative abduction Bayesian style. In particular, we discuss use-novel predictions, confirmation, and the problem of underdetermination in the context of abductive inferences.

How (not) to understand weak measurements of velocities

To-date, the most elaborated attempt to complete quantum mechanics by the addition of hidden variables is the de Broglie-Bohm (pilot wave) theory (dBBT). It endows particles with definite positions at all times. Their evolution is governed by a deterministic dynamics. By construction, however, the individual particle trajectories generically defy detectability in principle. Of late, this lore might seem to have been called into question in light of so-called weak measurements. Due to their characteristic weak coupling between the measurement device and the system under study, they permit the experimental probing of quantum systems without essentially disturbing them. It is natural therefore to think that weak measurements of velocity in particular offer to actually observe the particle trajectories. If true, such a claim would not only experimentally demonstrate the incompleteness of quantum mechanics: it would provide support of dBBT in its standard form, singling it out from an infinitude of empirically equivalent alternative choices for the particle dynamics. Here we examine this possibility. Our result is deflationary: weak velocity measurements constitute no new arguments, let alone empirical evidence, in favour of standard dBBT; One must not naïvely identify weak and actual positions. Weak velocity measurements admit of a straightforward standard quantum mechanical interpretation, independent of any commitment to particle trajectories and velocities. This is revealed by a careful reconstruction of the physical arguments on which the description of weak velocity measurements rests. It turns out that for weak velocity measurements to be reliable, one must already presuppose dBBT in its standard form: in this sense, they can provide no new argument, empirical or otherwise, for dBBT and its standard guidance equation.

Conventionalism about what? Where Duhem and Poincaré part ways

This paper examines whether, and in what contexts, Duhem's and Poincaré's views can be regarded as conventionalist or structural realist. After analysing the three different contexts in which conventionalism is attributed to them-in the context of the aim of science, the underdetermination problem and the epistemological status of certain principles-I show that neither Duhem's nor Poincaré's arguments can be regarded as conventionalist. I argue that Duhem and Poincaré offer different solutions to the problem of theory choice, differ in their stances towards scientific knowledge and the status of scientific principles, making their epistemological claims substantially different.