Samir Okasha

A number of recent philosophers, including Michael Williams, Barry Stroud and Donald Davidson, have argued that scepticism about the external world stems from the foundationalist assumption that sensory experience supplies the data for our beliefs about the world. In order to assess this thesis, I offer abrief characterisation of the logical form of sceptical arguments. I suggest that sceptical arguments rely on the idea that many of our beliefs about the world are ‘underdetermined’ by the evidence on which they are based. Drawing on this characterisation of scepticism, I argue that Williams, Stroud andDavidson are right to see the foundationalist assumption as essential to the sceptic’s argument, but wrong to think that scepticism is inevitable once that assumption is in place. By pursuing an analogy with some recent debates in the philosophy of science, I try to locate the additional assumptions which the sceptic must make, in order to derive her conclusion.

:This paper explores the contrast between mentalistic and behaviouristic interpretations of decision theory. The former regards credences and utilities as psychologically real, while the latter regards them as mere representations of an agent's preferences. Philosophers typically adopt the former interpretation, economists the latter. It is argued that the mentalistic interpretation is preferable if our aim is to use decision theory for descriptive purposes, but if our aim is normative then the behaviouristic interpretation cannot be dispensed with.

This chapter presents a displacement of the organism as a privileged level of analysis in evolutionary biology. It is concerned with the ontology of biology systems, with particular reference to hierarchical organization. It argues that the concept of a rank-free hierarchy can be transposed to the major transitions hierarchy, with interesting consequences. This chapter shows that the idea of rank freedom makes good sense of a number of facets of the recent discussion of evolutionary transitions and multilevel selection. It suggests that the idea of rank freedom is already at work, implicitly, in much theorizing about evolutionary transitions and/or multilevel selection.

Advocates of the "strong programme" in the sociology of knowledge have argued that, because scientific theories are "underdetermined" by data, sociological factors must be invoked to explain why scientists believe the theories they do. I examine this argument, and the responses to it by J.R. Brown (1989) and L. Laudan (1996). I distinguish between a number of different versions of the underdetermination thesis, some trivial, some substantive. I show that Brown's and Laudan's attempts to refute the sociologists' argument fail. Nonetheless, the sociologists' argument falls to a different criticism, for the version of the underdetermination thesis that the argument requires, has not been shown to be true.

Holistic claims about evidence are a commonplace inthe philosophy of science; holistic claims aboutmeaning are a commonplace in the philosophy oflanguage. W. V. Quine has advocated both types ofholism, and argued for an intimate link between thetwo. Semantic holism may be inferred from theconjunction of confirmation holism andverificationism, he maintains. But in their recentbook Holism: a Shopper's Guide, Jerry Fodor andErnest Lepore (1992) claim that this inference isfallacious. In what follows, I defend Quine's argumentfor semantic holism from Fodor and Lepore'smulti-pronged attack.

This paper compares two well-known arguments in the units of selection literature, one due to , the other due to . Both arguments concern the legitimacy of averaging fitness values across contexts and making inferences about the level of selection on that basis. The first three sections of the paper shows that the two arguments are incompatible if taken at face value, their apparent similarity notwithstanding. If we accept Sober and Lewontin's criterion for when averaging genic fitnesses across diploid genotypes is illegitmate, we cannot accept Sober and Wilson's criterion for when averaging individual fitnesses across groups is illegitimate, and vice versa. The final section suggests a possible way of reconciling the two arguments, by invoking an ambiguity in the concept of genic selection.

Biologists and philosophers of biology typically regard essentialism about speciesas incompatible with modern Darwinian theory. Analytic metaphysicians such asKripke, Putnam and Wiggins, on the other hand, believe that their essentialist thesesare applicable to biological kinds. I explore this tension. I show that standard anti-essentialist considerations only show that species do not have intrinsic essential properties. I argue that while Putnam and Kripke do make assumptions that contradict received biological opinion, their model of natural kinds, suitably modified, is partially applicable to biological species. However, Wiggins'' thesis that organisms belong essentially to their species is untenable, given modern species concepts. I suggest that Putnam''s, Kripke''s and Wiggins'' errors stem from adopting an account of the point of scientific classification which implies that relationally-defined kinds are likely to be of little value, an account which is inapplicable to biology.

What is science? Is there a real difference between science and myth? Is science objective? Can science explain everything? This Very Short Introduction provides a concise overview of the main themes of contemporary philosophy of science. Beginning with a short history of science to set the scene, Samir Okasha goes on to investigate the nature of scientific reasoning, scientific explanation, revolutions in science, and theories such as realism and anti-realism. He also looks at philosophical issues in particular sciences, including the problem of classification in biology, and the nature of space and time in physics. The final chapter touches on the conflicts between science and religion, and explores whether science is ultimately a good thing.

Many philosophers agree that Hume was not simply objecting to inductive inferences on the grounds of their logical invalidity and that his description of our inductive behaviour was inadequate, but none the less regard his argument against induction as irrefutable. I argue that this constellation of opinions contains a serious tension. In the light of the tension, I re-examine Hume’s actual sceptical argument and show that the argument as it stands is valid but unsound. I argue that it can only be converted into a sound one if our inductive behaviour can be characterized as a process of rule-governed ampliation. Drawing on some Bayesian ideas, I argue that our inductive behaviour probably cannot be characterized in that way, so our immunity from Hume is secure. Finally, I compare my response to Hume’s argument with some other well known responses.

Group selection is one acknowledged mechanism for the evolution of altruism. It is well known that for altruism to spread by natural selection, interactions must be correlated; that is, altruists must tend to associate with one another. But does group selection itself require correlated interactions? Two possible arguments for answering this question affirmatively are explored. The first is a bad argument, for it rests on a product/process confusion. The second is a more subtle argument, whose validity (or otherwise) turns on issues concerning the meaning of multi-level selection and how it should be modelled. A cautious defence of the second argument is offered. Introduction Multi-level selection and the evolution of altruism Price's equation and multi-level selection Contextual analysis and multi-level selection The neighbour approach Recapitulation and conclusion.

For a number of years, the debate in evolutionary biology over the ’levels of selection’ has attracted intense interest from philosophers of science. The main question concerns the level of the biological hierarchy at which natural selection occurs. Does selection act on organisms, genes, groups, colonies, demes, species, or some combination of these? According to traditional Darwinian theory the answer is the organism -- it is the differential survival and reproduction of individual organisms that drives the evolutionary process. But there are alternative views too, including pluralist views which say that the choice between different levels of selection is often a matter of perspective, not empirical fact.