Stathis Psillos

In this paper we defend the view that mechanisms are underpinned by networks of difference-making relations. First, we distinguish and criticise two different kinds of arguments in favour of an activity-based understanding of mechanism: Glennan’s metaphysics- first approach and Illari and Williamson’s science-first approach. Second, we present an alternative difference-making view of mechanism and illustrate it by looking at the history of the case of scurvy prevention. We use the case of scurvy to argue that evidence for a mechanism just is evidence for difference-making relations.

For many old and new mechanists, Mechanism is both a metaphysical position and a thesis about scientific methodology. In this paper we discuss the relation between the metaphysics of mechanisms and the role of mechanical explanation in the practice of science, by presenting and comparing the key tenets of Old and New Mechanism. First, by focusing on the case of gravity, we show how the metaphysics of Old Mechanism constrained scientific explanation, and discuss Newton’s critique of Old Mechanism. Second, we examine the current mechanistic metaphysics, arguing that it is not warranted by the use of the concept of mechanism in scientific practice, and motivate a thin conception of mechanism (the truly minimal view), according to which mechanisms are causal pathways for a certain effect or phenomenon. Finally, we draw analogies between Newton’s critique of Old Mechanism and our thesis that the metaphysical commitments of New Mechanism are not necessary in order to illuminate scientific practice.

There seems to be widespread agreement that there are two modal values: necessity and possibility. X is necessary if it is not possible that not-X; and Y is possible if it is not necessary that not-Y. In their path-breaking book, Rani Lill Anjum and Stephen Mumford defend the radical idea that there is a third modal value, weaker than necessity and stronger than possibility. This third value is dubbed 'dispositional modality' (DM) or 'tendency' and is taken to be an irreducible and sui generis worldly modality: "the modality that's everywhere" (5). The source of DM is the causal powers of particulars; hence, DM is constitutively involved in causation: "a cause tends or disposes towards its effect, and can sometimes succeed in producing it" (9). Accordingly, DM is involved in all causal processes, from fundamental physics to the social and moral realm. This "deeply tendential view" (11) of the metaphysics of nature is advanced as distinct from both extant neo-Aristotelian and Humean views. Its key feature is that there is neither pure contingency nor necessitation in nature.

Thomas Hobbes based his natural philosophy on definitions and general principles of matter in motion, which he refrained from calling “laws of nature.” Across the channel, René Descartes had presented his own account of matter in motion in such a way that laws of nature play a central causal-explanatory role. Despite some notable differences in the two systems of natural philosophy, the content of the three Cartesian laws of nature is shared by Hobbesian principles of motion. Why is it the case that Hobbes never ‘transferred’ the concept of law of nature from the sphere of civil society to the realm of nature? What is the status of the Hobbesian principles of motion if they are not laws? Answering these questions is the main aim of this article. It is shown that Hobbes made available an importantly different and genuinely original way to do natural philosophy, which renders it free of metaphysics and eschews the need to ground it in anything other than ‘natural reason’. Briefly put, Hobbes took the category of ‘laws of nature’ to involve commitments that cannot be met in the natural world, unless natural philosophy loses its autonomy from theology and metaphysics.

Some philosophers argue that tying scientific understanding to explanation and truth generates a dilemma for a realist view of science: given the practice and the history of science, either we should give up the idea that understanding requires truth, or we should accept that we do not have scientific understanding. Given, we were told, that the latter horn is repugnant, we should jettison the first horn and disconnect understanding and truth. In this paper, I argue that the alleged dilemma for realism is a non-starter. We can accept both that understanding requires truth and claim that theories offer understanding. I argue that understanding and explanation in science go hand in hand, and that—for a realist at least—they should both be world-involving.

In the present paper, I offer a conceptual argument against the view that all properties are pure powers. I claim that thinking of all properties as pure powers leads to a regress. The regress, I argue, can be solved only if non-powers are admitted. The kernel of my thesis is that any attempt to answer the title question in an informative way will undermine a pure-power view of properties. In particular, I focus my critique on recent arguments in favour of pure powers by the Late George Molnar and Jennifer McKitrick. The lines of defence of the friends of powers converge on what I call 'the ultimate argument for powers', viz., that current physics entails (or supports) the view that the fundamental properties (spin, mass, charge) are ungrounded powers. I take issue with this argument and make a modest suggestion: that the evidence from current physics is inconclusive

The very idea of a general philosophy of science relies on the assumption that there is this thing called science —as opposed to the various individual sciences. In this programmatic piece I make a case for the claim that general philosophy of science is the philosophy of science in general or science as such. Part of my narrative makes use of history, for two reasons. First, general philosophy of science is itself characterised by an intellectual tradition which aimed to develop a coherent philosophical view of science, qua a part of culture with distinctive epistemic features and a distinctive relation to reality. But, second, this tradition went through some important conceptual shifts which re-oriented it and made it more sensitive to the actual development of science itself. The historical narrative focuses on three such moments: the defining moment, associated with Aristotle, and two major conceptual turns, related to Kant and Duhem. The pressures on the very idea of a general philosophy of science that followed the collapse of the macro-models of science that became popular in the 1960s, the pressures that lay all of the emphasis on fragmentation and not on integration, can be dealt with by a new synthesis within general philosophy of science of the constitutive and the historical, in light of the intellectual tradition that has defined it

In this paper, I examine Azzouni's tracking requirement and its use as a normative constraint on theories about objects which we take as real. I focus on what he calls ‘thick epistemic access’ and argue that there is a logical–conceptual sense in which thick access to the real presupposes thin access to it. Then, I move on to advance an alternative—Sellarsian—way to ontic commitment and show that (a) it is better than Azzouni's, and (b) it can accommodate thick epistemic access as a bonus. Finally, I try to defend the Quinean theoretical virtues against some of Azzouni's objections. Introduction Theoretical irrealism vs holistic realism On the epistemic authority of observation The myth of the levels Quinean virtues Conclusion.

This paper is structured around the three elements of the title. Section 2 claims that (a) structures need objects and (b) scientific structuralism should focus on in re structures. Therefore, pure structuralism is undermined. Section 3 discusses whether the world has `excess structure' over the structure of appearances. The main point is that the claim that only structure can be known is false. Finally, Section 4 argues directly against ontic structural realism that it lacks the resources to accommodate causation within its structuralist slogan.

The aim of this paper is to rebut two major criticisms of the No-Miracles Argument for Realism. The first comes from Musgrave. The second comes from Colin Howson. Interestingly enough, these criticisms are the mirror image of each other. Yet, they both point to the conclusion that NMA is fallacious. Musgrave’s misgiving against NMA is that if it is seen as an inference to the best explanation, it is deductively fallacious. Being a deductivist, he tries to correct it by turning it into a valid deductive argument. Howson’s misgiving against NMA is that if it is seen as an inference to the best explanation, it is inductively fallacious. Being a subjective Bayesian, he tries to correct it by turning it into a sound subjective Bayesian argument. I will argue that both criticisms are unwarranted

Subjective Bayesianism is the current orthodoxy in confirmation theory. In broad outline, this view claims a) that confirmation is a relation of positive relevance, viz., that a piece of evidence confirms a theory if it increases its probability; b) that this relation of confirmation is captured by Bayes’s theorem; c) that, hence, the only factors relevant to confirmation of a theory are its prior probability, the likelihood of the evidence given the theory and the probability of the evidence; d) that the specification of the prior probability of a theory is a purely subjective matter; e) that the only constraint on an assignment of prior probabilities to several theories should be that they obey the axioms of the probability calculus; f) that, hence, the reasonableness of a belief does not depend on its content; nor, ultimately, on whether the belief is made reasonable by the evidence; and g) that degrees of belief are probabilities and that belief is always a matter of degree. This theory has had many successes. Old tangles, like the ravens paradox or the grue problem, are resolved. New tangles, like the problem of old evidence, have been, to some extent, resolved. But there is still a pervasive dissatisfaction with subjective Bayesianism. This dissatisfaction concerns all of the theses to above, but it is centred mostly around the point that subjective Bayesianism is too subjective to offer an adequate theory of confirmation and of rational belief. Yet, up until recently this dissatisfaction had not borne fruits in a fully developed alternative theory of confirmation. Perhaps, only Deborah Mayo’s error-statistical approach was a fully developed alternative, but this too faced considerable problems, one central among them being that she takes all probabilities to be relative frequencies. One thing is sure. Probability theory should place a central role in a theory of confirmation. But how are we to interpret probabilities if we want to avoid the subjective element of Bayesianism and the objective element of the error-statistical approach?

In his intervention to the ‘bankruptcy of science debate’, which raged in Paris in the turn of the twentieth century, Leo Tolstoy was one of the first to use the past record of science as a weapon against current science. It is not inductive. It does not conclude that all current scientific theories will be abandoned; nor that most of them will be abandoned; not even that it is more likely than not that all or most of them will be abandoned. Its conclusion is modest: some of presently accepted theories will have the fate of those past theories that once dominated the scene but subsequently were abandoned.

A thumbnail sketch of the philosophical thinking about the a priori would surely include that it has been dominated by two major approaches: the Kantian absolute conception of it and the Millian-Quinean absolute rejection of it (section 2). Yet, one can find in the literature claims about the existence of a ›functional a priori‹, a ›relative a priori‹, a ›relativised a priori‹ and suchlike. They are all meant to carve a space between the two extremes. An important thought behind the search for a middle ground is that the supposed coincidence between the constitutive and the unrevisable is wrong. The entitlement to accept a principle as being constitutive of experience prior to any empirical justification of it is compatible with an entitlement to revise or abandon such a principle on empirical grounds. If a priori principles are meant to be independent of experience, how should this claim of independence be understood so that room is left for the possibility that a principle is both independent of experience and revisable on empirical grounds (section 3)? A straightforward and natural way to approach this issue is to think of constitutive principles along the lines of Poincaréan conventions, which can be seen as delineating a new sense of the a priori – the conventional a priori principles. These are substantive principles that are constitutive of theoretical frameworks – in the sense that they define (or constitute) the object of knowledge – without being either synthetic a priori or empirical generalisations. Still, their negation is conceivable and they are revisable on empirical grounds (section 4).

In this paper I articulate RVC with an eye to two things: first, its conceptual development; second, its basic commitments and implications for what causation is. I have chosen to present RVC in a way that respects its historical origins and unravels the steps of its articulation in the face of objections and criticism. It is important for the explication and defence of RVC to see it as a view of causation that emerged in a certain intellectual milieu. RVC has been developed as an attempt to remove efficiency from causation and hence, to view causation not as a productive relation but as a relation of dependence among discrete events. In particular, the thought that causation is regularity is meant to oppose metaphysical views of causation that posit powers or other kinds of entity that are supposed to enforce the regularities that there are in the world or to explain the alleged necessity that there is in causation.

Traditionally, philosophers have focused mostly on the logical template of inference. The paradigm-case has been deductive inference, which is topic-neutral and context-insensitive. The study of deductive rules has engendered the search for the Holy Grail: syntactic and topic-neutral accounts of all prima facie reasonable inferential rules. The search has hoped to find rules that are transparent and algorithmic, and whose following will just be a matter of grasping their logical form. Part of the search for the Holy Grail has been to show that the so-called scientific method can be formalised in a topic-neutral way. We are all familiar with Carnap’s inductive logic, or Popper’s deductivism or the Bayesian account of scientific method.

Chakravartty claims that science does not imply any specific metaphysical theory of the world. In this sense, science is consistent with both neo-Aristotelianism and neo-Humeanism. But, along with many others, he thinks that a neo-Aristotelian outlook best suits science. In other words, neo-Aristotelianism is supposed to win on the basis of an inference to the best explanation (IBE). I fail to see how IBE can be used to favour neo-Aristotelianism over neo-Humeanism. In this essay, I aim to do two things. Firstly, I explain why this failure is not idiosyncratic: it should be there even by Chakravartty's lights. Secondly, I raise some critical worries about Chakravartty's semirealism, especially in connection with the concept of a 'concrete structure' and the detection/auxiliary distinction. The essay ends with a dilemma: an exclusive disjunction encapsulated in its title

When we think of scientific realism, there seem to be to ways to conceive of what it is about. The first is to see it as a view about scientific theories; the second is to see it as a view about the world. Some philosophers, most typically from Australia, think that the second way is the correct way. Scientific realism, they argue, is a metaphysical thesis: it asserts the reality of some types of entity, most typically, unobservable entities. I agree that scientific realism has a metaphysical dimension, but I have insisted that it has other dimensions too. In my (1999), I took scientific realism to consist of three theses (or stances).