One of the best-known arguments of 20^th century philosophy (of language) is the Private Language Argument (PLA). It is also the argument that immediately comes to mind when people think of the philosophy of the later Wittgenstein. At times it was regarded as a conclusive verdict on major versions of mentalistic philosophy, in the last twenty years debates shifted to disagreement both on the impact of the argument and its nature, and –surprisingly one may think given its former popularity — on its exact location in the loosely connected paragraphs of Wittgenstein's Philosophical Investigations.

Nielsen's The Evolution of the Private Language Argument traces the development of the PLA both in Wittgenstein's development as well as in the reception of the Philosophical Investigations (PI) within (analytic) philosophy. He divides the history of the PLA (and his book) into a period between the world wars, in which we find precursors of the later argument, the period of the immediate reception of the PI in the 1950s and early 1960s, and the still continuing reception of the PLA in a context of a new understanding of language in philosophy, starting in the 1970s. The appendices present short forms of the different versions of the PLA discussed in the book, as well as some original German passages from Wittgenstein.

The philosophers of the Vienna Circle (especially Carnap and Neurath) had an interest in securing the objectivity of science and scientific language, and thus in the rejection of both phenomenalism as well as Cartesianism as both precluded a universal physicalistic language of science. Carnap therefore advanced his own private language argument in the early 1930s. He aims to show that any putative non-physical statement (say about feelings or perceptions) has at least a physical translation. Referential privacy would lead to incommunicability, but Carnap does not exclude — as the PLA supposedly does — that subjects constantly associate something different with identical protocol sentences. Neurath proposed a diachronic private language argument to the effect that only public available protocols could avoid slips of memory. These two strands of argumentation (against the foundation of meaning in a Cartesian theatre and some scepticism about memory) recur in the interpretation and reception of the PLA. Wittgenstein — although not sharing Carnaps and Neurath epistemological concerns — even saw Carnaps version of the argument as some form of plagiarism. Wittgenstein's own concern with private language developed when he realized that his former support to at least the possibility of some phenomenological language (in the picture theory of the Tractatus) did not square with his physicalism. The essential idea present in all interpretations of the PLA is: Language/meaning and belief work by making a distinction between truth/being right and believing to be right. This idea Wittgenstein employs in his early versions of arguments against private languages (in the early 1930s). Privacy can play no explanatory role with respect to meaning and language, as justification can only be a public procedure. The later picture of language as existing only as a communal practice is not yet present here. With his later conception of language and philosophy privacy (in the terminological sense of the PLA) is not expressible (if possible at all). The early Wittgenstein versions of the PLA leave room for the existence of private objects, the PI at least can be read as denying their existence!

The reception of the PI included bewilderment about the point of the PLA. Malcolm (as Wittenstein's pupil) explained the PLA as rooted in concerns about verification: as the private thinker cannot be sure about right and only believing to be right there is no way to use his language meaningfully. How much of his earlier verificationism Wittgenstein still held in the PI is a difficult point, however. Further on, verificationism fell out of fashion after the end of the Vienna Circle. Thus, a better interpretation may focus not just on the problem of justifying the use of an expression in private, but on establishing a meaningful sign in private in the first place. Although this interpretation is nowadays regarded as on the right track, this idea resulted first in a sideline discussion about the possibility of private ostensive definitions. Rhees (another Wittgenstein pupil) hinted at the essential importance of the social character of language in Wittgenstein's later philosophy, but his explanation was neither clear nor successful. With a focus on Wittgenstein's new theory of language (present for example in Kenny's reading of Wittgenstein) the PLA came into clearer focus. Nielsen also shows how one can then better understand its relation to Wittgenstein's theory of expressive language use and the meaning of psychological vocabulary.

A curiosity of the 1980s was Kripke's misinterpretation of Wittgenstein as a skeptic about meaning, which nonetheless brought about new interest in the PLA. The debate centered on the proper understanding of rule-following and the PI theory of meaning. 'By and large, developments and refinements in the private language argument have led to developments and refinements in our understanding of Wittgenstein.' (155)

Nielsen sees the progression of the interpretations seemingly as coming to a better (i.e. more appropriate) understanding of the PI. He agrees basically in his comments and interpretation with the currently authoritative PI comments by Hacker (4 volumes) and von Savigny (2 volumes). Their interpretation sees the PLA as an illustration of Wittgenstein's new theory of language and meaning as being constituted by the social practice the individual speaker attunes to within her community. Nielsen's book is no substitute for their explanation of the structure and content of the PLA within the broader context of the PI. He seems to endorse an interpretation which stresses the 'purpose for which an expression is employed' (175) and a 'criterion … by which one can explain one's use of words' (162), which sounds like a mixture of teleological and justificationist concepts, rather than the communal agreement interpretation (where the fact of the agreement is the only justification of proper use and measure of correctness) as given by von Savigny or Hacker.

Nielsen's rejection of dissenters to the PLA (like Jerry Fodor and other cognitive scientist working with a language of thought hypothesis) is rather swift.

Nielsen's book fits into the growing literature looking into the origin and development — and some believe demise — of analytic philosophy. So it is interesting to learn that the Vienna Circle and Wittgenstein at some point had related interests in the rejection of a private language. The coverage of the historical and philosophical background one liked to go deeper at these points, especially so, since the book shows that supposedly autonomous pieces of philosophical reasoning have a reception history that links them to the (philosophical) fashions and moods of the time. Nielsen's concern being 'to understand the evolution of argumentation against the possibility of a private language, and in particular to trace the way in which hat argumentation was connected with, and reflected, the ideas and agendas that spawned it in different periods' (177).

Missing in this history is, as well, the broader reception of the PLA in the social sciences and the humanities in general. The turn to foundations in communication (from Peter Winch to Jürgen Habermas) is related to a reception of Wittgenstein and his supposed refutation of a foundation of a theory of (social) action — and thus social science — with a model of a solus ipse. Further on, Wittgenstein has become a reference for philosophies which are in no way analytic.

Thus The Evolution of the Private Language Argument is far from a comprehensive history of the PLA, but is a good start and especially the first part sheds light on the beginnings of Wittgenstein's later philosophy and the prominent role of the philosophy of (ordinary) language.

© 2008 Manuel Bremer

Manuel Bremer, Heinrich-Heine-Universität Düsseldorf, Germany

Keywords: Wittgenstein, private language, philosophy