A Lifelong Crusoe and Wittgenstein's Private Language Argument

Undoubtedly Robinson Crusoe has been around for some time and he'll be around for some time to come: he's very much a part of us now. Even if we haven't read the story, we know the basic outline. Crusoe is shorthand for man-alone-on-an-island.

*

I forget--or have lost track of--where I first ran into the idea of a "lifelong Crusoe," but almost certainly it was in relation to Wittgenstein's Private Language Argument.

From Mark Addis's Wittgenstein: A Guide for the Perplexed:

   A controversial issue is whether a solitary individual could follow a rule. It should be observed that this is not the matter of whether an individual can follow rules which are particular to himself and unknown to the rest of the linguistic community. Instead the question is whether it is possible for an individual to follow a rule in the absence of a community. This problem is usually cast in terms of a lifelong Crusoe who is characterized as an individual isolated from birth with a language devised for his own purposes but without having first learnt a language from another. The received view is that it is highly doubtful whether a lifelong Crusoe would engage in activities which would appropriately be termed rule-following. Some commentators, such as Baker and Hacker (1985), oppose the standard position in holding that such a lifelong Crusoe could follow his own rules agreeing over time with himself in judgements and behaviour. Even if not psychologically possible it is conceivable that a lifelong Crusoe should employ some kind of language and follow rules in doing so. 

*

I've not been able to trace the term "lifelong Crusoe" back to Wittgenstein (I've looked in his Philosophical Investigations--where much of the material on the so-called Private Language Argument can be found--but to no avail), but here is an excerpt from early in his Philosophical Investigations in which he seems to be touching on this eventually controversial idea of a Private Language (from PI, Part I, 243):

   But could we also imagine a language in which a person could write down or give vocal expression to his inner experiences--his feelings, moods, and the rest--for his private use?----Well, can't we do so in our ordinary language?--But that is not what I mean. The individual words of this language are to refer to what can only be known to the person speaking; to his immediate private sensations. So another person cannot understand the language.