Ever since David Hume, empiricists have barred powers and capacities from nature. In this book Cartwright argues that capacities are essential in our scientific world, and, contrary to empiricist orthodoxy, that they can meet sufficiently strict demands for testability. Econometrics is one discipline where probabilities are used to measure causal capacities, and the technology of modern physics provides several examples of testing capacities (such as lasers). Cartwright concludes by applying the lessons of the book about capacities and probabilities (...) to the explanation of the role of causality in quantum mechanics. (shrink)

How can philosophy of science be of more practical use? One thing we can do is provide practicable advice about how to determine when one empirical claim is relevant to the truth of another; i.e., about evidential relevance. This matters especially for evidence-based policy, where advice is thin—and misleading—about how to tell what counts as evidence for policy effectiveness. This paper argues that good efficacy results (as in randomized controlled trials), which are all the rage now, are only a very (...) small part of the story. To tell what facts are relevant for judging policy effectiveness, we need to construct causal scenarios about will happen when the policy is implemented. (shrink)

For evidence-based practice and policy, randomised controlled trials (RCTs) are the current gold standard. But exactly why? We know that RCTs do not, without a series of strong assumptions, warrant predictions about what happens in practice. But just what are these assumptions? I maintain that, from a philosophical stance, answers to both questions are obscured because we don't attend to what causal claims say. Causal claims entering evidence-based medicine at different points say different things and, I would suggest, failure to (...) attend to these differences makes much current guidance about evidence for medical and social policy misleading. (shrink)

How can philosophy of science be of more practical use? One thing we can do is provide practicable advice about how to determine when one empirical claim is relevant to the truth of another; i.e., about evidential relevance. This matters especially for evidence-based policy, where advice is thin—and misleading—about how to tell what counts as evidence for policy effectiveness. This paper argues that good efficacy results (as in randomized controlled trials), which are all the rage now, are only a very (...) small part of the story. To tell what facts are relevant for judging policy effectiveness, we need to construct causal scenarios about will happen when the policy is implemented. (shrink)

In this sequence of philosophical essays about natural science, the author argues that fundamental explanatory laws, the deepest and most admired successes of modern physics, do not in fact describe regularities that exist in nature. Cartwright draws from many real-life examples to propound a novel distinction: that theoretical entities, and the complex and localized laws that describe them, can be interpreted realistically, but the simple unifying laws of basic theory cannot.

Many, if not most, of our highly prized ‘laws’ of physics cannot be adequately rendered as statements of regular association among the values of ‘categorical’ quantities, I have argued.63 This is true even if we do not balk at the concept of natural necessity and are willing to add that the associations hold ‘by law’. They are rather ascriptions of capacities. They tell us what capacities a system will have by virtue of having a given property. The law of gravity (...) is one example. A system of mass M has the capacity of strength GMm/r2 to move another object of mass m a distance r away towards itself. I call this the gravitational capacity. My second thesis is a commonly shared one. Ascriptions of capacities do not reduce to conditionals involving only categorical properties. I shall here discuss two questions about these theses: 1) Why think of capacities as akin to dispositions or powers; and 2) Why allow them in science? Before tackling the first question, I shall first try to figure out what features we expect to be characteristic of dispositions and powers themselves. (shrink)

"Ce volume presente la seconde partie d'une etude sur l'angelologie medievale dont la premiere partie a paru dans cette meme collection sous le titre: 'Les anges et la philosophie: subjectivite et fonction cosmologique des substances separees au XIIIe siecle', Etudes de philosophie medievale LXXXII, Paris, 2002"--T.p. verso.

A partir de questions sur l'ange, son individualité, sa position et sa fonction par rapport aux autres êtres, dans l'architecture cosmologique et dans la structure métaphysique de l'univers, les penseurs médiévaux élaborent des théories autour de la structure et du sens de l'ordo rerum, et d'un paradigme de la subjectivité. Par le biais de ce dernier, l'ange figure le meilleur de l'humanité.

"Ce volume presente la seconde partie d'une etude sur l'angelologie medievale dont la premiere partie a paru dans cette meme collection sous le titre: 'Les anges et la philosophie: subjectivite et fonction cosmologique des substances separees au XIIIe siecle', Etudes de philosophie medievale LXXXII, Paris, 2002"--T.p. verso.

The volume brings together for the first time original essays by leading philosophers working on powers in relation to metaphysics, philosophy of natural and social science, philosophy of mind and action, epistemology, ethics and social and political philosophy. In each area, the concern is to show how a commitment to real causal powers affects discussion at the level in question. In metaphysics, for example, realism about powers is now recognized as providing an alternative to orthodox accounts of causation, modality, properties (...) and laws. Dispositional realist philosophers of science, meanwhile, argue that a powers ontology allows for a proper account of the nature of scientific explanation. In the philosophy of mind there is the suggestion that agency is best understood in terms of the distinctive powers of human beings. Those who take virtue theoretic approaches in epistemology and ethics have long been interested in the powers that allow for knowledge and/or moral excellence. In social and political philosophy, finally, powers theorists are interested in the powers of sociological phenomena such as collectivities, institutions, roles and/or social relations, but also in the conditions of possibility for the cultivation of the powers of individuals. The book will be of interest to philosophers working in any of these areas, as well as to historians of philosophy, political theorists and critical realists. (shrink)

Knowledge of causal laws is expensive and hard to come by. But we work hard to get it because we believe that it will reduce contingency in planning policies and in building new technologies: knowledge of causal laws allows us to predict reliably what the outcomes will be when we manipulate the factors cited as causes in those laws. Or do they? This paper will argue that causal laws have no special role here. As economists from JS Mill to Robert (...) Lucas and David Hendry stress, along recently with philosophers like James Woodward and Sandra Mitchell, they can do the job only if they are invariant under the manipulations proposed. But then, I shall argue, anything that is invariant under the proposed manipulations will do this job equally well. There seems to be nothing special about causal-law knowledge in and of itself that makes it particularly valuable for policy and technology prediction. What seems to matter is invariance alone, not causality. But what guarantees invariance and how do we know when it will obtain? Here certain kinds of causal laws do have a special place – those underwritten either by what I have called ‘nomological machines’ or by what I have called ‘capacities’. Capacities and nomological machines have a double virtue that makes them invaluable for policy planning. First, the causal laws they give rise to will be invariant so long as they obtain; and second, they typically have visible markers we can come to recognize that tell us when they obtain. The markers for nomological machines are shakier than those for capacities, though, since capacities are often tied to markers by well-established empirical laws. Capacities have their own drawback however, which is the final topic of this paper: the causal laws that are guaranteed by a capacity connect the obtaining of a capacity with its exercise. But Hume argued that no distinction can be made between the obtaining of a power and its exercise. (shrink)

The claims of RCTs to be the gold standard rest on the fact that the ideal RCT is a deductive method: if the assumptions of the test are met, a positive result implies the appropriate causal conclusion. This is a feature that RCTs share with a variety of other methods, which thus have equal claim to being a gold standard. This paper describes some of these other deductive methods and also some useful non-deductive methods, including the hypothetico-deductive method. It argues (...) that with all deductive methods, the benefit that the conclusions follow deductively in the ideal case comes with a great cost: narrowness of scope. This is an instance of the familiar trade-off between internal and external validity. RCTs have high internal validity but the formal methodology puts severe constraints on the assumptions a target population must meet to justify exporting a conclusion from the test population to the target. The paper reviews one such set of assumptions to show the kind of knowledge required. The overall conclusion is that to draw causal inferences about a target population, which method is best depends case-by-case on what background knowledge we have or can come to obtain. There is no gold standard. (shrink)

Are the laws of nature consistent with contingency about what happens in the world? That depends on what the laws of nature actually are, but it also depends on what they are like. The latter is the concern of this chapter, which looks at three views that are widely endorsed: ‘Humean’ regularity accounts, laws as relations among universals, and disposition/powers accounts. Given an account of what laws are, what follows about how much contingency, and of what kinds, laws allow? In (...) all three cases, the authors argue, the root idea of what laws are does not settle the issue of whether they allow contingency. Advocates of the different accounts may argue for one view or another on the issue, but this will be an add-on rather than a consequence of the basic view about what laws are. -/- . (shrink)

In addition to the notion of causal law, the concept of capacity, modelled on Mill's notion of tendency, is required to make sense of standard methods in econometrics and standard accounts of probabilistic causality. General causal claims are shown to be ascriptions of capacities while causal laws are local causal claims, relative to a test population. Capacities are at a higher level of modality and are not reducible to causal laws, as causal laws are not reducible to laws of association (...) that describe mere regularities; but unlike laws of association, capacities are real. (shrink)

The claims of RCTs to be the gold standard rest on the fact that the ideal RCT is a deductive method: if the assumptions of the test are met, a positive result implies the appropriate causal conclusion. This is a feature that RCTs share with a variety of other methods, which thus have equal claim to being a gold standard. This paper describes some of these other deductive methods and also some useful non-deductive methods, including the hypothetico-deductive method. It argues (...) that with all deductive methods, the benefit that the conclusions follow deductively in the ideal case comes with a great cost: narrowness of scope. This is an instance of the familiar trade-off between internal and external validity. RCTs have high internal validity but the formal methodology puts severe constraints on the assumptions a target population must meet to justify exporting a conclusion from the test population to the target. The paper reviews one such set of assumptions to show the kind of knowledge required. The overall conclusion is that to draw causal inferences about a target population, which method is best depends case-by-case on what background knowledge we have or can come to obtain. There is no gold standard. (shrink)

This article agrees with Philip Kitcher that we should aim for a well-ordered science, one that answers the right questions in the right ways. Crucial to this is to address questions of use: Which scientific account is right for which system in which circumstances? This is a difficult question: evidence that may support a scientific claim in one context may not support it in another. Drawing on examples in physics and other sciences, this article argues that work on the warrant (...) of theories in philosophy of science needs to change. Emphasis should move from the warrant of theories in the abstract to questions of evidence for use. (shrink)

It is often supposed that the spectacular successes of our modern mathematical sciences support a lofty vision of a world completely ordered by one single elegant theory. In this book Nancy Cartwright argues to the contrary. When we draw our image of the world from the way modern science works - as empiricism teaches us we should - we end up with a world where some features are precisely ordered, others are given to rough regularity and still others behave (...) in their own diverse ways. This patchwork makes sense when we realise that laws are very special productions of nature, requiring very special arrangements for their generation. Combining classic and newly written essays on physics and economics, The Dappled World carries important philosophical consequences and offers serious lessons for both the natural and the social sciences. (shrink)

The study of plant signaling and behaviour, whose aim is to address the physiological basis for adaptive behaviour in plants, is a growing and thought-provoking field of research. In this review we discuss relevant studies that try to interpret in a neurocognitive fashion cases in which plants seem to behave similarly to animals. By comparing observations and experiments about plants and animals, we propose a framework composed of three axes in which interactions of living organisms with the world can be (...) represented. The first axis refers to adaptiveness, the second to sensitivity, and the third to sentience. This model allows us to interpret the behaviours of living organisms along a continuum capable of giving a smooth transition from simple to complex responses. In light of this, plants show an excellent adaptiveness, a variable level of sensitivity, and a good degree of sentience (restricted to the immediate perception that something is happening to themselves). Only the organisms with a high degree of sentience can have the basis for developing consciousness. However, even though it is necessary for consciousness, sentience is not sufficient, as it must be associated with a complex functional organization of structures that can support a recursive and synchronized processing of information. So far, plants have been found to completely lack this type of organization. Plants appear to be, therefore, sentient but not conscious. (shrink)

This paper critically analyses the concept of evidence in evidence-based-policy arguing that there is key problem: that there is no existing practicable theory of evidence, one which is philosophically grounded and yet applicable for evidencebased policy. The paper critically considers both philosophical accounts of evidence and practical treatments of evidence in evidence-based-policy. It argues that both fail in different ways to provide a theory of evidence that is adequate for evidence-basedpolicy. The paper is a valuable contribution to the part of (...) the research project that explores how evidence can and should be used to reduce contingency in science, and policy based on science. (shrink)

Causation is in trouble—at least as it is pictured in current theories in philosophy and in economics as well, where causation is also once again in fashion. In both disciplines the accounts of causality on offer are either modelled too closely on one or another favoured method for hunting causes or on assumptions about the uses to which causal knowledge can be put—generally for predicting the results of our efforts to change the world. The first kind of account supplies no (...) reason to think that causal knowledge, as it is pictured, is of any use; the second supplies no reason to think our best methods will be reliable for establishing causal knowledge. So, if these accounts are all there is to be had, how do we get from method to use? Of what use is knowledge of causal laws that we work so hard to obtain? (shrink)

‘Singular Causes First’ rejects Hume's thesis that singular causal facts are reducible to generic ones, adopting a reverse position, taking singular causes as basic. Using idealized examples, Cartwright shows that strategies to establish causal claims without using singular causal facts as inputs all fail, including probabilistic theories of causality. Not only is singular causal input necessary if probabilities are to imply causal connections, the resulting causal output is also at base singular.

Modern science relies heavily on Galilean idealization, which establishes ceteris paribus laws—laws about what happens when a factor operates unimpeded. But these laws are of little direct use since factors seldom do operate unimpeded. The follow‐up to Galilean idealization is abstraction—we talk simply of what the factor does. The best way to understand this abstraction is as an ascription of a capacity, not in terms of any kind of laws. Even the process of ‘de‐idealization’ or of ‘concretization’ that results in (...) a concrete phenomenological law inevitably involves further concepts in the capacity family. (shrink)