Here's my take on it. Academic philosophy in the US is highly focused on making completely clear claims with a rigor approaching that of mathematical logic. It is more or less pursuing the program Wittgenstein sketched in his first book, the Tractatus, creating a collection of concepts and network of relationships among them in which apparent philosophical paradoxes vanish. This is the analytical tradition. It is nice because it is indeed rigorous, but it can be limiting because it severely constrains the topics you can talk about. Something as big and multifarious as, say, Heidegger's notion of Dasein does not fit into this mold. And certainly nothing written as poetically as Nietzsche would pass muster.
In his second book, Philosophical Investigations, Wittgenstein completely rejected this approach, and his earlier work. He claimed that....well, no one's really sure what he claimed, or that he really claimed anything, and that's exactly the problem academic philosophers have with him. To a first approximation, he claimed that the whole idea of language as a formal system was either wrong or a waste of time, and that language is better thought of as some kind of game.
The thinking, then, is that later Wittgenstein was not making a clear point, was not interested in making a clear point, and possibly was not even serious at all. Philosophical Investigations is an enigma, and modern academic philosophy doesn't deal in such things.
I've never felt enticed to read a book by any philosopher, but that kind of made curious!
Especially given the comment about language could be seen as some kind of game, about which I'd say he's at least then partially been shown to be right? Being understood is very much a game, as you without anticipating your counterparts expectations and knowledge are often hopefully lost. Though I don't know if that's even close to what he was referring to, so yes, a but curious.
The idea of a "language game" was merely an analogy. It wasn't meant to trivialize the subject. The point is that language is an activity that operates according to conventional rules. (This also relates to his argument against "private language", though I'm personally not as convinced by that.) If you were to give a short summary of Wittgenstein's philosophy, I think it's better to say that he claimed meaning is use. "For a large class of cases—though not for all—in which we employ the word "meaning" it can be defined thus: the meaning of a word is its use in the language." This is in opposition to traditional analytic philosophy which holds that the meaning is specified by external references and truth conditions.
Somebody should tell Philosophers about the Curry-Howard-Lambek isomorphism.
Because that's all there is to the Mathematical notion of "rigorous proof".
And the 'next step' in scaling up this process is the mission undertaken by the NuPRL project [1] well on our road towards internalising systems theory as the mode of scientific discourse [2]:
Starting with the slogan "proofs-as-programs," we now talk about "theories-as-systems."
In his second book, Philosophical Investigations, Wittgenstein completely rejected this approach, and his earlier work. He claimed that....well, no one's really sure what he claimed, or that he really claimed anything, and that's exactly the problem academic philosophers have with him. To a first approximation, he claimed that the whole idea of language as a formal system was either wrong or a waste of time, and that language is better thought of as some kind of game.
The thinking, then, is that later Wittgenstein was not making a clear point, was not interested in making a clear point, and possibly was not even serious at all. Philosophical Investigations is an enigma, and modern academic philosophy doesn't deal in such things.