The Pessimistic Meta-induction: Obsolete Through Scientific Progress?

Abstract

Recently, Fahrbach and Park have argued that the pessimistic meta-induction (PMI) about scientific theories is unsound. They claim that this very argument does not properly take into account scientific progress, particularly during the twentieth century. They also propose amended arguments in favour of scientific realism, which are supposed to properly reflect the history of science. I try to show that what I call the argument from scientific progress cannot explain satisfactorily why the current (best) theories should have reached a degree of success that excludes their future refutations and allows the inference to their truth. I further argue that this line of argumentation dismisses the burden of proof in a rather unfair manner by using a delaying tactic to postpone the question about the validity of the PMI in the future.

Acknowledgements

I am very grateful for extensive comments from Claus Beisbart on earlier drafts of this paper. I would also like to thank the participants at a colloquium at the University of Berne in spring 2015 as well as the editor and the two anonymous referees of this journal for their elaborated feedbacks, which improved the paper significantly.

Notes

[1] Others have elaborated arguments in favour of scientific progress too (see e.g. McAllister 1993; Nola 2008; Roush 2010). However, the focus in this paper is on Fahrbach and Park, who are the most recognised in recent literature.

[2] The use of the term ‘success’ is fairly vague in the philosophical debate. The discussion still lacks a generally accepted definition. See, for example, Laudan (1981, 23) and Fahrbach (2011b, 1285).

[3] For reasons of simplicity I am using the notions of ‘truth’ and ‘approximate truth’ as equivalent. Thus, henceforth, when I use the notion of truth I also mean (approximate) truth. The realism debate still lacks a coherent definition of the terms. See, for example, Laudan (1981, 31–32) and Fahrbach (2011a, 60).

[4] Note that the meaning of the term ‘past theories’ in (I₁) and in (A₃) is not entirely clear (Park 2011, 79–80). The expression certainly serves as an antonym to ‘current theories’. But it may refer to slightly different sets of theories. Either it is used as a synonym for ‘old theories’ (which may still be considered to be true), or it refers to theories that have been refuted, superseded or at least been significantly changed. Park seems to prefer the reading of past theories as old theories. In his early papers, Fahrbach (2009, 2011a, 2011b) talks about refuted and current best theories rather than of past theories. In later work, however, Fahrbach (2012, 67) defines past theories explicitly as theories that were formulated at least 80 years ago.

[5] Park uses the notion ‘optimistic induction’ instead of ‘optimistic meta-induction’.

[6] An argument against PMI labelled OMI is also elaborated in Nola (2008) and Roush (2010). However, although their argumentation endorse the idea of scientific progress, their approaches go beyond, what I call the argument from scientific progress, strictly speaking. They do not discuss the argument from scientific progress as such as explicitly as Fahrbach and Park and their approaches differ significantly from the latters. Although I point towards some similarities, I leave it to further work to discuss Nola (2008) and Roush (2010) in detail.

[7] This is true for the (incomplete) list Laudan presents. By discussing structural geology elsewhere, he mentions a theory that was considered to be true until the 1960s. See Laudan (1981, 35).

[8] Saatsi’s conclusion was recently criticised by Mizrahi (2013). He has some interesting points, but I do not believe that he really replies to the critique at the heart of Saatsi’s objection. This is not the place to discuss Mizrahi in detail, but let me briefly indicate some criticism.

 First, in his critique of the PMI as reductio ad absurdum (i.e. the reductio reconstructed by Lewis 2001, 373), Mizrahi focuses solely on the premises (A₁) and (A₂) of the PMI₁. He does not discuss premise (A₃) and he does not engage with the question of the consequences that at least some successful theories turned out to be false, which should be answered to counter Saatsi. The same is true for his objections against the PMI as pointing to counterexamples. Thus, Mizrahi has no appropriate answer concerning the PMI₁ that contests the explanatory connection between the success and the truth of theories.

 Second, it seems to me that to accept Mizrahi’s argumentation one has to abandon the NMA, as Mizrahi proposes, a standpoint that is, according to my state of knowledge, far from being common sense among realists. Besides, this view does not prevent Mizrahi from referring to Putnam (1975) and (at least partly) to the NMA to refute the PMI as pointing to counterexamples (Mizrahi 2013, 3224–3225).

[9] Park substantially modifies the NMA with the criterion of the support of theories. The truth of a theory is no longer explained by success alone. According to Park, the truth is now the best explanation for the success and the support of theories. To what extent Park diverges from the commonly represented NMA is, however, not the subject of this article.

[10] As a matter of fact, Fahrbach (2011b, 2012) no longer claims the argument of OMI. Although he does not explicitly refer to the OMI, nonetheless, the NMA′ still entails the idea that we are allowed to infer from the stability of the current best theories to their truth.

[11] Realists might, however, answer that exactly these theories that remain stable over centuries reveal how successful the current best theories have been in the past.

[12] In my opinion, it would make sense to distinguish between technological progress and genuine scientific progress in the debate. That technological progress has literally transformed the way of life, and that efficiency has risen sharply in industrialised countries since the industrial revolution, should be unchallenged. The question, however, is whether technological and scientific progress can be considered as equivalent and whether scientific progress has been as strong as technological progress.

[13] Laudan (1981, 34) criticises the tautological character of the restriction of the NMA to mature theories too.