I am going to take the approach to the ordinary by Baudelaire and Wittgenstein and how they could be near each other in their views, even if they took it to different expressions.
I do not mean Baudelaire influenced Wittgenstein or that Wittgenstein’s philosophy is a codification of Baudelaire artistic attitude, I am only suggesting a connection and placing a possible thesis from it, so I ask the reader to have it as it is: an intellectual exercise and not some closed theory.
As I have already written, at the first sight, it might seem that they are not very related actually, only the fact that both of them treated with language, one with a writer/poet approach and the other with a philosophical/scientific approach (OK, in fact, we have here a first similarity: both of them approached reality through language).
But we can take some sentences from the Tractatus Logico-Philosophicus and Philosophical Investigations that are key-words for approaching the similarities between the views on ordinary by Wittgenstein and Baudelaire more explicitly. In their books, Wittgenstein says: «The whole sense of the book might be summed up in the following words: what can be said at all can be said clearly, and what we cannot talk about we must pass over in silence and it may seem that X is the case but in reality Y is the case. This expression is not used to mean that there is some special dimension of being where Y is true although X is true in our dimension. What it really means is X seemed right, but appearances were misleading». To Wittgenstein the secret of reality, of the ordinary, does not reside in what is real or not but in our way to express it, the words we use, recognizing the limits they have or the limits we have to actually practice reality. Things that are obviously are; the question is not if they are or not, but how to express them.
We could say that the attitude took on by Baudelaire before reality is a practical way to express in some manner what is theorized in the Tratactus, and that Paris Spleen is a Guerrilla Manual for it, even if it precedes the Tractatus in time.
Baudelaire rejects the ordinary, i.e. the form reality has taken in his own days. If Wittgenstein finds out that language is wrongly used and, therefore, that the way it is done must be revised, to Baudelaire the language of ordinary is mundane in the worst sense of this term, so it must be used in another way, it must be subverted. He did it so in his poems: «Which of us has not [...] dreamt the miracle of a poetic prose», he writes. But he took it to the real/ordinary itself, theorizing and taking the role of Dandy and Flanêur, and subverting this way not only the language as writing, but its symbolic/social expression too.
In the themes Wittgenstein and Baudelaire find each other; Wittgenstein, as a philosopher in the classic sense, was only theorizing, Baudelaire, as the true modernist artist he was, was taking action also.