Department of Level 2 Module

PHI230 Philosophy of

LECTURER: George Botterill Office Hours Wed 12-1, Fri 1-2; external tel: (0114)2220580; email: [email protected]

Lectures: Monday 2-3 in Hicks Building LT6 Friday 11-12 in Hicks Building LT5 Seminars: See MOLE unit to join: Monday 4-5 Jessop Building 215, Friday 12-1 Jessop Building 215

GENERAL OUTLINE This course will deal with major issues in the , with particular emphasis on the rationality of theory-change, explanation, the status of scientific laws, , and the structure of scientific theories. Most of the course will be devoted to the methodology of , though we may also discuss some issues in the philosophy of the social .

Most of the issues presented revolve around two major debates in the philosophy of science: (1) the dispute between Kuhn and Popper about theory change (2) disagreements between positivist (or instrumentalist) and realist conceptions of science. Modern philosophy of science has become closely linked with the . The course will reflect this by considering how well major developments in the history of science fit proposed methodological rules about how science ought to proceed. The Copernican Revolution in astronomy will be used as a case-study.

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AIMS AND OBJECTIVES The main aims of this module are: • to introduce students to the debate about theory-change in science, deriving from the work of Popper, Kuhn, Feyerabend and Lakatos • to help students acquire an understanding of some important problems in the philosophy of science (concerning the topics of: explanation, observation, , and the of laws) • to encourage students to enter into serious engagement with some of the major problems in the philosophy of science. There is a great deal of material to be covered in this course. The philosophy of science is a large area, with many specialist branches (e.g. , philosophy of , probability and confirmation theory) — some of which we must omit altogether, or discuss only in a limited way. Most importantly, there are some difficult and unresolved problems (such as: How to judge the outcome of the Popper-Kuhn-Lakatos debate? or: Can we provide a general account of explanation? or: Is there an acceptable form of scientific realism?) that pose challenges which should stimulate students to active philosophical engagement in their own work.

GENERAL READING • Modern classics in the philosophy of science: Kuhn, T.S. 1962: The Structure of Scientific Revolutions. Univ. of Chicago Press. Popper, K.R. 1963. and Refutations. : . Feyerabend, P.K. 1975: . London: New Left Books. Lipton, P. 1991/2004: Inference to the Best Explanation. London: Routledge. [If you want to buy any books, these are the choices most likely to be of lasting value.]

• There are two leading periodicals you will probably wish to consult at some point: Philosophy of Science and the British Journal for the Philosophy of Science (both to be found in Stack 4 at PER 105, though also easy to access through the Library's Ejournals).

• Good general guides through the philosophy of science are: Chalmers, A.F. 1978/1982/1999: What Is This Thing Called Science?. Press. Newton-Smith, W.H. 1981: The Rationality of Science. Routledge, London. Rosenberg, A. 2005 (3rd edn 2011): The Philosophy of Science: a contemporary introduction. Routledge, London.

• Two good survey articles, both written by David Papineau, are: ‘Methodology: The elements of the philosophy of science’, ch.3 in A.C. Grayling (ed), Philosophy: a guide through the subject, Oxford University Press, 1995. ‘Philosophy of Science’, ch. 9 in N. Bunnin and E.P. Tsui-James (eds), The Blackwell Companion to Philosophy, Blackwell: Oxford, 1996.

• Useful anthologies:

2 Boyd, R., Gasper, P. and Trout, J.D. (eds) 1991: The Philosophy of Science. Cambridge, Mass.: MIT Press. [Boyd et al. 1991] at 142(P) Hacking, I. 1981: Scientific Revolutions. Oxford readings in philosophy. Oxford University Press. at 142(S) Papineau, D. 1996: The Philosophy of Science. Oxford readings in philosophy. Oxford University Press. [Papineau 1996] at 142(P) Ruben, D-H. 1993: Explanation. Oxford readings in philosophy. Oxford University Press. [Ruben 1993 —a very good collection, but sadly out of print.] Newton-Smith, W.H. (ed) 2000: A Companion to the Philosophy of Science. Oxford: Blackwell. Comprehensive and so somewhat encyclopaedic in treatment, but useful for purposes of reference. [Newton-Smith 2000] at 501 (C)

• Hitchcock, C. 2004: Contemporary Debates in Philosophy of Science. Oxford: Blackwell. This for-and-against collection has good sections on: thought-experiments, and predictive success as an argument for scientific realism.

ASSESSMENT

Assessment is by a combination of coursework and examination, 50% of the final grade being derived from two essays and 50% from a two hour examination paper. For essay titles and further details concerning coursework please consult the Coursework Summary.

Examination: Students will be allowed two hours in which to answer two questions. The questions on the examination paper will be pre-released.

3 Syllabus Part 1: The Big Debate about Theory-Change (Popper-Kuhn-Lakatos) and the Copernican Revolution Topics and Reading: #1 and the #2 Popper’s Falsificationism #3 Kuhn on Normal and Revolutionary Science #4 The Copernican Revolution #5 Lakatos’ Methodology of Research Programmes

#1 Inductivism and the Problem of Induction It’s important to realise that whether provides the basic method of -formation and whether induction can be rationally justified are distinct issues. For it seems clear that Inductivism (the view that theories are and should be arrived at by a process of inductive generalization of regularities discovered through observation) is an inadequate methodological view — because it confuses discovery and justification, and cannot do justice to the creativity involved in theorizing. But it also seems clear that we cannot do without using some forms of inductive reasoning (despite what Popper — see below — claims). Probably the main task in justifying induction is to give a good description of what inductive inferences are to be justified. Many think of induction as Induction by Simple Enumeration. This has the advantage of being a well-defined formal process, but is definitely too simplistic as an account of our actual inductive practices. Mill’s methods of experimental perhaps merit a section of their own. They are also of relevance to the sections on contrastive explanation and inference to the best explanation. The interest of Mill’s methods lies, practically, in the that they are directly related to experimental design; and, theoretically, in the possibility that they provide a way of approaching inductive reasoning that does not take enumerative generalization as the basic or primary case of induction. See also the sections on Goodman’s Paradox and Inference to the Best Explanation for further attempts to characterise defensible forms of inductive inference.

Further Reading Russell, B.1912. The Problems of Philosophy, 33-8. Reprinted in Swinburne R ed, The Justification of Induction, 19-25. A classic statement. Chalmers, A.F. What Is This Thing Called Science?, ch 2, 12-19. Will, FL.1947. Will the future be like the past?. 56: 332-47. Edwards, P.1949. Russell’s doubts about induction. Mind 58: 141-63. Reprinted in Swinburne R ed, The Justification of Induction, 26-47. Strawson, P.F. 1952 Introduction to Logical Theory, ch 9.II The "justification" of induction, 248-63. Ayer, A.J. Probability and Evidence, ch 1 The legacy of Hume Harman, G. 1965. The inference to the best explanation. Philosophical Review 74, pp.88-95. Popper, K.R.1963. Conjectures and Refutations, paper 10

4 Popper, K.R. 1972. Objective Knowledge, ch 1 Blackburn. S. Reason and Prediction, ch 1. (against Strawson and Edwards!) Stove, D.C. 1986. The Rationality of Induction Mill, J.S. 1843. A System of : Ratiocinative and Inductive, BkIII Ch.VIII ‘Of the Four Methods of Experimental Inquiry’ [The first edition of Mill’s A System of Logic was published in March 1843. He introduced a large number of revisions and corrections, working through to an 8th edition in 1872. The best modern text is to be found in Volumes VII-VIII of the Collected Works of , ed. J.M. Robson, University of Toronto/Routledge & Kegan Paul, 1973. You can find it in the Library at 136 (Mill).] Scarre. G. Mill on induction and , in J. Skorupski ed., The Cambridge Companion to Mill, Cambridge UP: 1998, pp.112-38

#2 Popper’s Falsificationism According to Popper, a theory is only scientific if it is falsifiable. This is his famous Demarcation Criterion, which is intended to differentiate genuine science from both and “pseudo-science”. Popperian falsificationism has several important merits: it accounts for the emphasis on in scientific inquiry; it offers a plausible diagnosis of what’s wrong with certain theories; it promises an account of the rational and progressive nature of science; and it spares us many of the problems and intricacies of confirmation theory. There are, however, several serious objections to Popper’s position. A particularly important one concerns the role of auxiliary hypotheses in scientific theorizing. I shall refer to it as the Duhemian point (although it is more often — and quite inaccurately — called “the Duhem-Quine Thesis”), after . Note that this objection seems to have been independently discovered by Lakatos and Putnam.

Further Reading Popper, K.R. 1963. Conjectures and Refutations, first paper Popper, K.R. 1972. Objective Knowledge, ch 1 Putnam, H. 1974. The ‘corroboration’ of theories. In Schilpp PA ed, The Philosophy of Vol I, 221-40. Reprinted in Hacking I ed, Scientific Revolutions, 60-79; and in Putnam H, Mathematics, Matter and Method, 250-69; and in Boyd et al. 1991, 121-37. Watkins, J. Popper. In Newton-Smith 2000, pp.343-8 Duhem, P. 1906 trans 1954. The Aim and Structure of Physical Theory, ch 6: 180-90. Lakatos, I. 1974. Popper on demarcation and induction. In Schilpp PA ed, The Philosophy of Karl Popper, 241-73. Reprinted in Lakatos I, The Methodology of Scientific Research Programmes, Philosophical Papers Vol 1, 139-67.

#3 Kuhn on Normal and Revolutionary Science ‘ invites us to think of scientific progress as exercises in imitation interrupted by changes in fashion.’ (Sylvain Bromberger)

Kuhn himself characterizes the general objective of his work:

5 ‘as an attempt to show that existing theories of rationality are not quite right and that we must readjust or change them to explain why science works as it does. To suppose, instead, that we possess criteria of rationality which are independent of our understanding of the essentials of the scientific process is to open the door to cloud- cuckoo land.’ Criticism and the Growth of Knowledge, p.264 Kuhn divides scientific activity into two mutually interdependent but quite distinct categories: and revolutionary science. Normal science is ‘research firmly based upon one or more past scientific achievements’. It consists mainly in ‘puzzle-solving’ within a particular theoretical framework – within a particular , in Kuhn’s terminology. It’s a gradual, somewhat derivative activity, filling in the details, elaborating on themes already conceived. Revolutionary science, by contrast, is a period of discontinuity, one edifice being overthrown and another theoretical structure raised up in its place. What strikes Kuhn's critics as particularly alarming is that he does not think that in scientific revolutions new theories triumph over old because of crucial experiments. On the contrary Kuhn maintains that experiments are only thought of as crucial with hindsight, and moreover if theories were only assessed on hard factual criteria (rather than on such factors as promise and aesthetic appeal) there would be hardly any revolutionary changes in science. While normal science proceeds through a series of struggles to eliminate anomalies (apparent counterinstances), a revolutionary phase sets in when the weight of anomalies encountered within that particular tradition grows too great for the scientific community to bear. Such a situation makes scientists more receptive to novel theories – in particular, novel theories that can deal with anomalies which a lavish expenditure of scientific has failed to reconcile with the old theory. Thus the ability to explain previously anomalous phenomena is regarded as strongly confirming the new theory: ‘Probably the single most prevalent claim advanced by the proponents of a new paradigm is that they can solve the problems that have led the old one to a crisis. When it can legitimately be made, this claim is often the most effective one possible...’ The Structure of Scientific Revolutions, p.153

Further Reading Kuhn, T.S.1962. The Structure of Scientific Revolutions [especially ch.III The Nature of Normal Science, ch.X Revolutions as Changes of World View, and ch.XII The Resolution of Revolutions] Rorty, R. Kuhn. In Newton-Smith 2000, pp.203-6 Popper, K.R. Objective Knowledge, pp.13-21 Lakatos, I. & Musgrave, A., eds.1970. Criticism and the Growth of Knowledge [most of the papers are relevant, but particularly J.W.N. Watkins: ‘Against normal science’, pp.25-37; K.R. Popper: ‘Normal science and its dangers’, pp.51-8; and T.S. Kuhn on ‘Irrationality and theory-choice’, pp.259-66 — in which Kuhn denies that he is an irrationalist.] Chalmers, A.F. What Is This Thing Called Science? ch.8

#4 The Copernican Revolution We take the history of astronomy as our case-study (to see whether it fits any of the methodological moulds provided by Popper, Kuhn, and Lakatos) because it is a

6 widely accessible subject, because the Copernican revolution was of such great historical significance in the development of modern science, and because it is a well studied area in the history of science, frequently cited in philosophical debates. A little study of the history of planetary astronomy should also disabuse us of several popular misconceptions. Thus, Greek astronomers realised as early as the 5th century BC that the earth was spherical, not flat — why else would Eratosthenes go on to calculate its circumference? The device of the epicycle, as used by Ptolemy, was not such a horribly ad hoc and overcomplicated resource — and, besides, Copernicus used epicycles too. It is of particular interest that — the ‘Copernican theory’ that the planets revolve around the sun — had already been proposed by Aristarchus of Samos. As Ptolemy (c.150AD) explains in The Almagest, however, it was regarded as refuted by empirical observation, viz. 1) the absence of any observed stellar parallax, and 2) none of the effects in the terrestrial environment that might be supposed to result from the earth’s rotation.

Further Reading Kuhn, T.S. 1957. The Copernican Revolution, chs 5-6 Dreyer, J.L.E. [1906/1953] A History of Astronomy from Thales to Kepler, chs 13-15. Koestler, A. The Sleepwalkers, Pt I & Pt III Feyerabend, P.K. 1975. Against Method, chs 6-11 Lakatos, I & Zahar, E.G. 1976. Why did Copernicus’s programme supersede Ptolemy’s?. In Westman R ed, The Copernican Achievement, 354-83. Reprinted in Lakatos I, The Methodology of Scientific Research Programmes, Philosophical Papers Vol 1, 168-92. Gingerich, O. ‘Galileo and the phases of Venus’. In his The Great Copernicus Chase, Cambridge UP: 1992, pp.98-104 **** Library Guide to further reading: Solar system astronomy is shelved at 520; history of astronomy is at 520.9; and works on Copernicus and Galileo in particular are at 520.92. ****

#5 Lakatos’ Methodology of Research Programmes Lakatos’s MRP, although originally proposed as a sophisticated version of Popperian falsificationism, looks to be a synthesis that combines what ought to be retained in the views of Popper and Kuhn. Lakatos proposes that research programmes are to be appraised over a period of time, according to whether they are progressive or degenerative. He thus avoids the relativism of Kuhn, while allowing a theory to prove its mettle by introducing modifications in the ‘protective belt’ of auxiliary hypotheses. “Neither the logician’s proof of inconsistency nor the experimental scientist’s verdict of anomaly can defeat a research programme in one blow. One can be ‘wise’ only after the event.” (Lakatos, 1971) The main point — against ‘naive falsificationism’ (Popper) — is that theories of a certain sort (of a mature science / in the ‘hard core’ / of a high level of theoreticity / framework theories) are not sharply falsifiable. They can be cumulatively disconfirmed by exhibiting ‘degenerating problem-shift’, but they can’t be decisively refuted or knocked out by a single crucial experiment. This has further consequences — notably, that Popper’s Demarcation Criterion cannot be upheld. Lakatos went on to suggest (see ‘History of science and its rational reconstructions’ in `the Howson volume) that methodologies can be checked out by the degree to which they accord with the history of science.

7 One can only be wise after the event. But when is that? Feyerabend (1971) objected that Lakatos’ criteria for rational theory change in science were bogus because it was not possible to specify any particular time at which assessment for progress or degeneration of a research programme should be carried out. A theory had to be given a chance ‘to prove its mettle’. But it is always possible that a previously degenerating research programme might be on the brink – after the next modification of auxiliaries – of a period of glorious progress.

Further Reading Kuhn, T.S. 1962 . The Structure of Scientific Revolutions, ch XII The Resolution of Revolutions. Lakatos, I. 1970. Falsification and the methodology of scientific research programmes. In Lakatos I & Musgrave A eds, Criticism and the Growth of Knowledge. Reprinted in Lakatos I, Philosophical Papers Vol 1. Lakatos, I. 1971. History of science and its rational reconstructions. In Howson C ed, Method and Appraisal in the Physical Sciences. Also in Hacking I ed, Scientific Revolutions; Lakatos I, Philosophical Papers Vol 1. Feyerabend, P.K. 1971. On the critique of scientific reason. In Howson C ed, Method and Appraisal in the Physical Sciences. Reprinted in Feyerabend PK, Philosophical Papers Vol II Problems of , under the title ‘The methodology of scientific research programmes’. Hacking I. 1979. ’s philosophy of science. British Journal for the Philosophy of Science XXX, 381-410. Revised extracts reprinted in Hacking I ed, Scientific Revolutions, 128-43. Larvor, B. 1998 Lakatos: an introduction. Routledge. Nickles, T. Lakatos. In Newton-Smith 2000, pp.207-12.

Syllabus Part 2: Explanation, Confirmation, and Scientific Realism

In Part 1 we looked at the major general debate between Popper, Kuhn and Lakatos about theory-change and rational progress in science, and tried to apply these different perspectives to the Copernican Revolution in astronomy. It is possible to see Lakatos’s MRP as combining what is right about Kuhn’s view of science (a theory must be given a chance to defend itself and deal with anomalies) with what is right about Popper’s methodological rules (there has to be an objective measure of superiority of one theory over another, to account for the rationality of scientific progress). But there are problems for Lakatos — notably the problem over the right time-limit for assessing the progress of a research programme. Also, it might be possible, as I suggested, to make do with a Minimalist Methodology which relies upon logical consistency, economy, and . That’s a suggestion that needs further development. But it appears that it would naturally produce structures in science like the research programmes Lakatos describes (i.e.: hard core theories plus amendment of auxiliaries guided by principles).

It has to be admitted that while we have learnt something from this about the role of auxiliaries and the fact that most theories are bound to run into anomalies, the Big

8 Debate about Theory-Change is very far from being resolved to everyone’s satisfaction. Some people have concluded that this is because one cannot say anything of much substance about scientific method in general: there are different areas of science and they may well have significantly different methodologies. Hence interest in philosophy of science over the last couple of decades has tended to splinter into , , philosophy of biology, etc.

We turn now to consider some general issues which appear to be of a philosophical character rather than part of History-and-Philosophy-of-Science.

Explanation Explanations are obviously a highly diverse bunch, differing in many ways. But is it nonetheless possible to give an analysis of what makes an explanation explanatory? It is quite a natural philosophical ambition to try to set out what all genuine explanations have in common with each other. A terminological start can be made by separating the explanandum (Latin for that which is to be explained) from the explanans (Latin for what does the explaining). That bit of jargon may save a few words; and we can further safely say that the explanans must supply some information. But then it gets difficult. Just what are the conditions that information must satisfy, in relation to a given explanandum, in order to constitute an explanation?

#6 The Deductive-Nomological Model of Explanation The Deductive-Nomological (or Covering Law) Model claims that adequate scientific explanations involve subsuming what is to be explained (the explanandum) under a general law, by displaying it as a deductively entailed consequence of statements of laws and initial conditions (the explanans). So on this view an explanation has the form of an argument, with the explanans as the premises and the explanandum as the conclusion – which makes giving an explanation much like deriving a prediction, only with hindsight. This is frequently cited, outside philosophy of science, as the conventional or orthodox view of scientific explanation. But, as you will see, within the philosophy of science the D-N Model has had few supporters since its great advocate, Carl Hempel. See, for example, Achinstein 1969 and Brody 1972 for severe objections. One diagnosis of where the D-N Model goes wrong is that it fails to require that the information supplied in the explanans should be about causes of the to be explained. That in turn suggests that theories of causal explanation should be explored – e.g., Woodward 1984, Lewis 1986.

Further Reading Newton-Smith, W.H. Explanation. In Newton-Smith 2000, pp.127-33. Achinstein, P. 1969. Law and Explanation, ch 5, pp.99-109 Achinstein, P. 1981. Can there be a model of explanation?. Theory and Decision 13, 201-27. Reprinted in Ruben 1993. Brody, B. 1972. Towards an Aristotelian theory of scientific explanation. Philosophy of Science 39, 20-31. Reprinted in Ruben 1993. Coffa, J.A. 1974. Hempel’s ambiguity. Synthese 28. Reprinted in Ruben 1993. Gasper, P. 1990. Explanation and scientific realism. In D. Knowles ed, Explanation and its Limits, 285-95 Harré, H.R. The of Science, p.56, p.61, and pp.168-83

9 Harré, H.R. The Principles of Scientific Thinking, ch 1, pp.15-21 Hempel, C.G. Explanation in science and in history. In R.G.Colodny ed, Frontiers of Science and Philosophy, 7-33. Reprinted in P.H.Nidditch ed, The Philosophy of Science, 54-79; and in Ruben 1993. Hempel, C.G. 1965. Aspects of Scientific Explanation, 245-95. Extract reprinted in Ruben 1993. Hempel, C.G. 1966. Philosophy of Natural Science, ch 5. Reprinted in Boyd et al. 1991. Hempel, C.G. & Oppenheim, P. 1948. Studies in the logic of explanation. Philosophy of Science 15, 135-78 Kim, J. 1987. Explanatory realism, causal realism, and explanatory exclusion. Midwest Studies in Philosophy 12, 225-39. In Ruben 1993. Kinoshita, J. 1990. How do scientific explanations explain?. In D. Knowles ed, Explanation and its Limits, 297-311 Kitcher, P. 1981. Explanatory unification. Philosophy of Science 48, 507-31. Reprinted in Boyd et al. 1991. Lewis, D. 1986 Causal explanation. In his Philosophical Papers, 214-40. Reprinted in Ruben 1993. Lipton, P. 1990. Contrastive explanation. In D. Knowles ed, Explanation and its Limits. Reprinted in Ruben 1993. Matthews, R.J. 1981. Explaining and explanation. American Philosophical Quarterly 18, 71-7. In Ruben 1993. Nagel, E. 1961. The Structure of Science, chs 2 and 3 Ryan, A.R. The Philosophy of the Social Sciences, ch 3 Scriven, M. 1962: Explanation, predictions, and laws. In H. Feigl and G. Maxwell (eds), Minnesota Studies in the Philosophy of Science Vol.III: Scientific Explanation, Space, and Time, Minneapolis: University of Minnesota Press, 170- 230. Taylor, D.M. Explanation and Meaning, ch 2 van Fraassen, B. 1977. The pragmatics of explanation. American Philosophical Quarterly 14,143-50. Reprinted in Boyd et al. 1991. Woodward, J. 1984. A theory of singular causal explanation. Erkenntnis 21. In Ruben 1993.

#7 Contrastive Explanation An important point to note is that requests for explanation are often formulated in terms of a contrast — Why P rather than Q? So there has been considerable interest over the past twenty years or so in contrastive explanation (which can be seen as a kind of causal explanation — see Lipton 1990). One major advantage of the contrastive account is that it imposes a limitation on the explanatory task, which is particularly important if explaining why something happened is a matter of supplying relevant causal history. For there is a vast causal history behind everything that happens. But if the task is to explain the contrast between a fact and a foil, then it looks as if it may be accomplised by indicating the prior factor which made the difference — even if we do not know all the background mechanisms and processes at work. Lipton’s Difference Condition tries to formulate this idea. We will be considering whether we need to amend Lipton’s account. Another point that should not be forgotten is that explaining is something that we do. Indeed, it is a kind of speech act. Without us in the world, there would be no shortage of causation. But absent humans and other intelligent life-forms, no

10 explaining would go on. If we take this point seriously then we should heed the importance of context. It’s tempting to suggest that what is the right (or best) explanation depends, at least to some extent, upon context. Would you offer the same explanation to a young child? To an intelligent layman? To an expert in the field? The explanation to be given clearly also depends upon the explanatory inquiry, what the question is (Hansson, 1974). In ‘Two Kinds of Causal Explanation’ I argue that there are systematic differences between two kinds of explanations: contrastive explanations, which are answers to why-questions; and process explanations, which are answers to how-questions.

Further Reading Botterill, G. 2010: ‘Two Kinds of Causal Explanation’. Theoria 76, pp.287-313. Day, M. and Botterill, G. 2008. Contrast, inference, and scientific realism. Synthėse, 160: 249-67. — Day and Botterill (2008) discusses the difference between compatible and incompatible contrasts; also introduces the idea of difference closure as exemplified by common garden and fast shadowing experiments. Garfinkel, A. 1981. Forms of Explanation. New Haven and London: Yale University Press. Hansson, B. 1974. Explanations — of what?. Stanford and Lund: unpublished typescript. Hesslow, G. 1985. Explaining differences and weighting causes. Theoria, 49: 87-111. Lewis, D. 1986. Causal explanation. In D. Lewis, Philosophical Papers II, Oxford: Oxford University Press, 214-40. Lipton, P. 1990. Contrastive explanation. In D. Knowles (ed), Explanation and Its Limits, Cambridge: Cambridge University Press. Lipton, P. 1991/2004. Inference to the Best Explanation. London: Routledge. Mill, J.S. 1843/1973. A System of Logic: Ratiocinative and Inductive, Books I-III. Toronto and Buffalo, and London: University of Toronto Press and Routledge & Kegan Paul. Schaffer, J. 2005. Contrastive causation. Philosophical Review 114: 327-58. Schweder, R. 1999. Causal explanation and explanatory selection. Synthėse 120:115- 124. van Fraassen, B. 1980. The Scientific Image. Oxford: Clarendon Press. Ylikoski, P. 2007. The idea of contrastive explanandum. In J. Persson and P. Ylikoski (eds), Rethinking Explanation, Place: Springer, 27-42.

#8 Two Famous Paradoxes: — Hempel’s Ravens The paradox is generated by the following , each of which seems quite plausible in itself: 1) of black ravens confirm ‘All ravens are black’ (and, more generally, positive instances confirm).

2) Observations of non-ravens are neutral with respect to the confirmation of ‘All ravens are black’.

11 3) If observations confirm one formulation of a , then they confirm any logically equivalent formulation. [3) is known as the Hypothesis Equivalence Condition, one version of which is: If h and h* are logically equivalent, and e confirms h*, then C(h/e) = C(h*/e).] BUT : (a) ‘All ravens are black’ is logically equivalent to (b) ‘All non-black things are non-ravens’; and also to (c) ‘Anything whatsoever, whether a raven or not, is either black or a non-raven’. Positive instances of (a) are black ravens; positive instances of (b) include such items as white handkerchiefs, green leaves, red post-boxes, etc. (anything that satisfies both antecedent and consequent, i.e. anything that is both non-black and not a raven); and positive instances of (c) are anything at all except for non-black ravens (note that (c) has more positive instances than (b) — e.g., such items as black shoes, black swans, etc.). Now, by 1) and 3), positive instances of (b) and (c) should also confirm ‘All ravens are black’. But by 2) they should be neutral with respect to the confirmation of ‘All ravens are black’. This constitutes the paradox.

Further Reading Mackie, J.L. 1963. ‘The Paradox of Confirmation’, British Journal for the Philosophy of Science 13: 265-77. Swinburne, R.G. (1971) ‘The Paradoxes of Confirmation: A Survey’, American Philosophical Quarterly vol. 8. Armstrong, D.M. ‘Critique of the Regularity Theory (3)’. Ch.4 of What is a Law of Nature?, Cambridge UP:1983, pp.39-59.

— Goodman’s Grue Let something be grue iff for any time tT, it is blue. Informally, we may say an object is grue just in case it’s green up to some specified time T or blue thereafter, if still in existence. The paradox is supposed to be generated by the following considerations, taking T to be some time in the future: everything that we have observed to be green we have also observed to be grue so every pre-T observation that is a positive instance of ‘All emeralds are green’ is also a positive instance of ‘All emeralds are grue’ BUT ‘All emeralds are green’ and ‘All emeralds are grue’ are different hypotheses which yield mutually inconsistent predictions about the colour of emeralds after T We could make T any time we like (8 am tomorrow, the beginning of next week, the start of the 21st century, etc.). Does this mean that previous observations of emeralds – every one of them green – provide just as good evidence for thinking that future emeralds will be blue as for thinking they will be green?

12 Projectively paradoxical predicate pairs A pair of predicates, F and G, will produce paradoxical projections if the following conditions are met: #1 Past (pre-T) observations that something is F are also observations that it is G #2 Future projection of the predicates F and G yield inconsistent predictions #3 F and G are symmetrical with respect to confirmation: i.e., observed members of some kind K having been found to be G is just as good a reason for thinking that other members of kind K are G as is the fact that observed members of kind K have been found to be F is for thinking that other members of kind K are F In attempting to resolve Goodman’s Paradox it’s #3 that looks the most promising requirement to question. Is the fact that previously observed emeralds have been grue any reason at all to think that ‘All emeralds are grue’? If not, why not? Can a scientific realist dissolve the paradox by saying that positive instances do not confirm in the absence of some underlying theoretical process or generating mechanism?

Further Reading Trout, JD. Confirmation, Paradoxes of. In Newton-Smith 2000, pp.53-5. Goodman, N. 1955. Fact, Fiction and Forecast, ch 3 Barker, S & Achinstein, P. 1960 On the new riddle of induction. Philosophical Review 69, 511-22. See also the reply ‘Positionality and pictures’ that follows by Goodman, pp.523-5. Both are reprinted in Nidditch PH ed, The Philosophy of Science, 149-61 and 162-4. Thompson, JJ. 1966. Grue. Journal of Philosophy LXIII, 289 Fain, H. 1967. The very thought of grue. Philosophical Review LXXVI, 61-73. Hooker, C.A. 1968. Goodman, ‘grue’, and Hempel. Philosophy of Science 35, 232-47. Blackburn, S. Goodman’s paradox. In Studies in the Philosophy of Science, American Philosophical Quarterly monograph series, 128-42. Blackburn, S. Reason and Prediction, ch 4 Hesse, M.B. 1969. Ramifications of grue. British Journal for the Philosophy of Science XX, 13-25. Hesse, M.B. The Structure of Scientific Inference, ch 3

#9 Scientific Realism — For and Against Realism about scientific theories seemed to be firmly established after the rejection of that started in the 1960s. Theories actually do postulate previously unobserved forces and entities and do attempt to describe the structure of the universe and its contents. (Though van Fraassen stubbornly holds out against this view, arguing that since in the end we could never discriminate between theories that are empirically adequate and theories that are actually true, we have no reason to aim for the latter rather than the former; see van Fraassen 1976, 1980, for his ‘’. Seems like positivism to me — and wrong for much the same reasons!) (Hacking 1982, 1983) has been influential, arguing that experimental manipulation and intervention commit us to realism more deeply than theory alone can. As he memorably put it, ‘If you can spray them, they exist!’. But there are two aspects to realism in science, which we can label realism of intent and realism of fact (see Botterill & Carruthers, The , ch.2). So, we are trying to describe causal mechanisms, micro-structures, and lawful connections between properties (realism of intent). But the realist surely wants to go

13 further and say that science has been largely successful in this enterprise (realism of fact) — that the world actually is the way scientific theories tell us it is. Here two notorious arguments have been advanced, pointing in opposite directions: • According to the No Miracles Argument, scientific theories make so many successful predictions and work so well in technological application that we ought to believe they are true, at least in the main. For it would just be miraculous, if they were false and so successful. The best explanation for their success is that they are (approximately, at any rate) true. • The contrary case is urged by the Pessimistic Meta-Induction (see Laudan 1981): most successful theories in the past have ultimately come to be rejected as false. Why should our theories be any different? The lesson that the history of science teaches (the meta-induction) is that, however successful they may be at any one time, scientific theories are probably false.

Further Reading Boyd, R. 1983. On the current status of scientific realism. Erkenntnis 19, 45-90. Reprinted in Boyd et al. 1991. Boyd, R. 1990. Realism, approximate truth, and philosophical method. In C.W. Savage, Scientific Theories, Minnesota Studies in the Philosophy of Science 14, 355-91. Reprinted in Papineau 1996. Fine, A. 1984. The natural ontological attitude. In J. Leplin ed, Scientific Realism, Univ. of California Press, 83-107. Reprinted in Boyd et al. 1991; and in Papineau 1996. Hacking, I. 1982. Experimentation and scientific realism. Philosophical Topics 13, 71-87. Reprinted in Boyd et al. 1991. Hacking, I. 1983. Representing and Intervening. Cambridge University Press. Laudan, L. 1981. A confutation of convergent realism. Philosophy of Science 48: 19- 48. Reprinted in Boyd et al. 1991; and in Papineau 1996. Laudan, L. 1987. Progress or rationality? The prospects for normative . American Philosophical Quarterly 24: 19-31. Leplin, J. 1986. Methodological realism and scientific rationality. Philosophy of Science 53: 31-51. Leplin J. Realism and . In Newton-Smith 2000, pp.393-401. Lipton, P. 1993. Is the best good enough?. Proceedings of the Aristotelian Society 93: 89-104. Reprinted in Papineau 1996. Quine, W. 1969. Natural kinds. In his Ontological Relativity and Other Essays, 114- 38. Reprinted in Boyd et al. 1991. Psillos, S. 1999. Scientific Realism: How science tracks truth. Routledge: London. Psillos, S. The present state of the scientific realism debate. In P. Clark and K. Hawley eds., Philosophy of Science Today, pp.59-82. Reiner, R. and Pierson, R. 1995. Hacking’s experimental realism: an untenable middle ground. Philosophy of Science 62: 60-69. van Fraassen, B. 1976. To save the phenomena. Journal of Philosophy 73, 623-32. Reprinted in Boyd et al. 1991; and in Papineau 1996. van Fraassen, B. 1980 The Scientific Image. Oxford University Press. Worrall, J. 1989. Structural realism: the best of both worlds?. Dialectica 43, 99-124. Reprinted in Papineau 1996. [Note: Almost all the papers in Papineau 1996 are on this topic.]

14 Syllabus Part 3: Prediction & Accommodation; Observation; Thought-Experiments

#10 Prediction and Accommodation Does ‘prediction’ [the derivation from a theory of previously unknown results] provide stronger evidence in favour of a theory than ‘accommodation’ [fitting known results in the process of theory-construction]? Suggestive example: Mendeleyev’s Periodic Table The fact that Mendeleyev included the 60 then known elements did not impress fellow scientists nearly so much as his prediction of two previously unknown elements. Lipton, p.134: ‘Sixty accommodations paled next to two predictions.’ So, is there a general advantage of prediction over accommodation? And, if so, why?

Further Reading Lipton, P. Inference to the Best Explanation, ch.8 Horwich, P. Probability and Evidence, Cambridge University Press, 1982, pp.108-17 Harker, D. 2006. Accommodation and prediction: the case of the persistent head. British Journal for the Philosophy of Science 57 . Harker, D. 2008. On the predilections for predictions. British Journal for the Philosophy of Science 59. pp.429-53.

#11 Observation Positivist philosophy of science (e.g. up to E. Nagel’s The Structure of Science, 1961) supposed that there was a given level of observation, which had a special epistemic status. Reports of observations were the sorts of thing we could directly know to be true. (This is a form of Epistemological .) This corresponded to a dichotomy between the observable and the unobservable. The problem for the positivists was how statements about unobservable theoretical entities could be meaningful. This they attempted to explain by means of upward seepage of meaning (the so-called ‘partial interpretation' account of theoretical significance). But from the early 1960s a number of philosophers of science – notably Kuhn (‘Revolutions as Changes of World-View’), Feyerabend (‘Consolations for the Specialist’), and N.R. Hanson (Patterns of Discovery) – argued very vigorously that all observation is theory-laden.

Further Reading Chalmers, AF. What Is This Thing Called Science?, ch. 3 Newton-Smith, WH. The Rationality of Science, ch. 2 Kuhn, T.S. 1962. The Structure of Scientific Revolutions, ch X Revolutions as changes of world-view. Maxwell, G. 1962. The ontological status of theoretical entities. Minnesota Studies in the Philosophy of Science Vol 3, 3-27. Achinstein, P. 1965. The problem of theoretical terms. American Philosophical Quarterly 2: 193-203. Achinstein, P. 1969. Concepts of Science, ch 6, 179-201. Hanson, N.R. Patterns of Discovery, ch 1 (also 2 & 3).

15 Ryle, G. Dilemmas, ch VI, 82-92. Churchland, P.M. Scientific Realism and the Plasticity of Mind, chs 1 & 2. Spector, M. 1966. Theory and observation. British Journal for the Philosophy of Science 17, part I 1-20, part II 89-104. Kordig, C.R. 1971. The theory-ladenness of observation. Review of Metaphysics 24. Shimony, A. 1977. Is observation theory-laden? A problem in naturalistic . In Colodny RG ed, Logic, Laws & Life, 185-208. Shapere, D. 1982. The concept of observation in science and philosophy. Philosophy of Science 49: 485-525. Fodor, J. 1984. Observation reconsidered. Philosophy of Science LI, 23-43. Torretti, R. 1986 Observation. British Journal for the Philosophy of Science 37, 1-23. Bogen, J. & Woodward, J.1988 Saving the phenomena. Philosophical Review 97: 303-52. Churchland,P.M.1988. Perceptual plasticity and theoretical neutrality: a reply to . Philosophy of Science 55: 167-87. Fodor, J. 1991. The dogma that didn’t bark. Mind 100: 201-20. Achinstein, P. Observation and Theory. In Newton-Smith 2000, pp.325-34.

#12 Thought-Experiments To anyone with empiricist sympathies the operation of learning something just by thinking about a possible situation ought to seem like a bit of cognitive magic. In carrying out any experiment we want to know what the results are. But in order to get any genuine results, surely we have actually to perform an experiment. Just imagining a situation, and then imagining a result — how could that be good for anything?

Further Reading Popper, K.R. 1957. The Logic of Scientific Discovery, Appendix *xi. ‘On the use and misuse of imaginary experiments, especially in quantum theory’, pp.442-56. Kuhn, T.S. A function for thought-experiments. In his The Essential Tension, University of Chicago Press: 1977, pp.240-65 Brown, J.R. The Laboratory of the Mind. London: Routledge, 1991 Sorensen, R.A. Thought Experiments. Oxford University Press, 1992 Norton, J. 1996. Are thought experiments just what you thought? Canadian Journal of Philosophy 26: 333-66. Gendler, T.S. 1998. Galileo and the indispensability of scientific thought experiments. British Journal for the Philosophy of Science 49, 397-424. Philosophy of Science 71:5 (2004) Colloquium: papers by Brown J.R., Norton J.D., Gendler T.S., and McAllister J.W., pp.1126-1175.

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