Alexander James Bird

In this paper I examine two aspects of Hempel’s covering-law models of explanation. These are (i) nomic subsumption and (ii) explication by models. Nomic subsumption is the idea that to explain a fact is to show how it falls under some appropriate law. This conception of explanation Hempel explicates using a pair of models, where, in this context, a model is a template or pattern such that if something fits it, then that thing is an explanation. A range of well-known counter-examples to Hempel’s models has led his successors to seek alternatives. Problems with limited amendments have encouraged some theorists of explanation to abandon nomic subsumption. So, in particular, causal components have come to be regarded as essential, even though Hempel had intended his model to capture causal explanation as well.1 Here I want to examine the prospects for retaining nomic subsumption by rejecting the other feature of Hempel’s approach – explication by models. An examination of the counter-examples will suggest that it is a mistake to imagine that a limited quantity of information about laws and antecedent conditions will be able to provide an actual explanation – other information, about explanations, may be relevant. This in turn leads me to examine what I shall call structural approaches. They are structural because the status of something as an explanation depends on its fitting into a structure of explanations. There are two structural approaches I shall examine. One is holistic – it proposes that we consider explanation hand-in-hand with the concept of law. This account of explanation inherits its holistic nature from the holistic (or sys- tematic) character of laws of nature. The second supervenience view I shall consider is not global as the holistic approach is. Instead it concentrates on the ‘vertical’ structure of explanations, whereby the existence of a nomic explanation at one level reflects explanations on lower levels on which it supervenes. These structural approaches were first proposed in Bird Synthese 120: 1–18, 1999. © 1999 Kluwer Academic Publishers..

1. Contextualism seeks to acknowledge the power of sceptical arguments while permitting to be true at least some of the assertions of knowledge and justification we commonly make. It seems to me now just as if I am in an office in Edinburgh. According to the sceptic the claim that I am in fact in an office in Edinburgh is unjustified, since there is no reason I can give for this belief that is not also consistent with (or undermined by) the alternative hypothesis that I am in fact on a beach in Hawaii being deceived by an evil demon into thinking that I am in an office in Edinburgh. Yet if I were..

It is widely agreed that many causal relations can be regarded as dependent upon causal relations that are in some way more basic. For example, knocking down the first domino in a row of one hundred dominoes will be the cause of the hundredth domino falling. But this causal relation exists in virtue of the knocking of the first domino causing the falling of the second domino, and so forth. In such a case, A causes B in virtue of there being intermediate events I1 . . . In such that A causes I1, I1 causes I2, . . . , In−1 causes In, and In causes B. Cases of this sort include my putting my foot on the brake causing the car to slow, the smoke from a fire causing the fire brigade to be alerted, and so forth. In other cases the more basic causal relations may not be intermediate (or at least it is controversial that they are). My seeing that it is raining may cause me to want to stay inside, and this causal relation depends upon more basic causal relations among various components of my brain. But it does not seem possible to analyze this in terms of my perception causing certain brain events, which cause other brain events, which eventually cause my desire. Rather it seems as if the principle causal relation, between perception and desire, is constituted, rather than mediated, by the more basic causal relations in the brain. The same is true of the operation of the dynamo causing the current to flow. Again there are not intermediate events, but rather the causal relation between them is constituted by the motion of the charged particles in the wires moving though a magnetic field, which causes an electric field, which causes the charges to move in the wire. There are thus at least two kinds of complex causal relation: the chain kind and the constitution kind. If we wish to understand causation, we need to understand the basic causal relations, at least as found in the chain kind. That is, to understand what it is for A to cause B when the latter is a causal relation of the chain kind, requires understanding what it is for the intermediate, basic causal relations to hold. In the case of a complex causal relation of the constitution kind, it is may be that understanding what it is for A and B to be causally related does not require understanding what it is for the constituting causal relations to hold..

Debates concerning the analysis of the concept of law of nature must address the following problem. On the one hand, our grasp of laws of nature is via our knowledge of their instances. And this seems not only an epistemological truth but also a semantic one. The concept of a law of nature must be explicated in terms of the things that instantiate the law. It is not simply that a piece of metal that conducts electricity is evidence for a law that metals conduct electricity. It is also the case that to explicate what it is for there to be such a law requires, and requires little more than, alluding to the fact that the piece of metal conducting electricity is an instance of that law. This is the driving intuition behind regularity theories of laws — to understand the concept ‘law,’ as in ‘it is a law that metals conduct electricity’ one need only understand little more than what it is for something to be a metal and to conduct electricity and the concept of universal generalization. On this view a law just is a regularity (or some kind of regularity) among its instances.

Dispositions are related to conditionals. Typically a fragile glass will break if struck with force. But possession of the disposition does not entail the corresponding simple (subjunctive or counterfactual) conditional. The phenomena of finks and antidotes show that an object may possess the disposition without the conditional being true. Finks and antidotes may be thought of as exceptions to the straightforward relation between disposition and conditional. The existence of these phenomena are easy to demonstrate at the macro-level. But do they exist at the fundamental level also? While fundamental finkish dispositions may be excluded fairly straightforwardly, the existence of fundamental antidotes is more open. Nonetheless I conclude that the phenomenon is likely to be less widespread than at the macro level and that fundamental antidotes may be eliminable. According to the dispositional essentialist, the laws of nature can be explained by taking natural properties to be essentially dispositional. This account can be extended to show that the existence of finks and antidotes explains ceteris paribus laws. Consequently the existence or otherwise of fundamental finks and antidotes sheds some light on the question of whether fundamental laws may also be ceteris paribus laws.

Kuhn’s Structure of Scientific Revolutions is one of the most cited books of the twentieth century. Its iconic and controversial nature has obscured its message. What did Kuhn really intend with Structure and what is its real significance? 1 Introduction 2 The Central Ideas of Structure 3 The Philosophical Targets of Structure 4 Interpreting and Misinterpreting Structure   4.1 Naturalism   4.2 World-change   4.3 Incommensurability   4.4 Progress and the nature of revolutionary change   4.5 Relativism, rationality, and realism   4.6 History and sociology of science   4.7 Wittgenstein 5 After Structure