In rough order, the first half of the book sets forth the following theses:
The world consists of independent atomic facts — existing states of affairs — out of which larger facts are built.
Language consists of atomic, and then larger-scale propositions that correspond to these facts by sharing the same "logical form".
Thought, expressed in language, "pictures" these facts.
We can analyse our thoughts and sentences to express ("express" as in show, not say) their true logical form.
Those we cannot so analyze, cannot be meaningfully discussed.
Philosophy consists of no more than this form of analysis: "Wovon man nicht sprechen kann, darüber muß man schweigen" ("Whereof one cannot speak, thereof one must be silent").
Some commentators believe that, although no other type of discourse is, properly speaking, philosophy, Wittgenstein does imply that those things to be passed over "in silence" may be important or useful,[33] according to some of his more cryptic propositions in the last sections of the Tractatus; indeed, that they may be the most important and most useful. He himself wrote about the Tractatus in a letter to his publisher Ficker:
“ ...the point of the book is ethical. I once wanted to give a few words in the foreword which now actually are not in it, which, however, I’ll write to you now because they might be a key for you: I wanted to write that my work consists of two parts: of the one which is here, and of everything I have not written. And precisely this second part is the important one. For the Ethical is delimited from within, as it were by my book; and I’m convinced that, strictly speaking, it can ONLY be delimited in this way. In brief, I think: All of that which many are babbling I have defined in my book by remaining silent about it. ”
—Wittgenstein, Letter to Ludwig von Ficker,October or November 1919, translated by Ray Monk
Other commentators point out that the sentences of the Tractatus would not qualify as meaningful according to its own rigid criteria, and that Wittgenstein's method in the book does not follow its own demands regarding the only strictly correct philosophical method.This also is admitted by Wittgenstein, when he writes in proposition 6.54: ‘My propositions are elucidatory in this way: he who understands me finally recognizes them as senseless’. These commentators believe that the book is deeply ironic, and that it demonstrates the ultimate nonsensicality of any sentence attempting to say something metaphysical, something about those fixations of metaphysical philosophers, about those things that must be passed over in silence, and about logic. He attempts to define the limits of logic in understanding the world.
The work also contains several innovations in logic, including a version of the truth table.
read about:http://www.tractatus.hochholzer.info/
http://www.kfs.org/~jonathan/witt/tlph.html
or maybe therehttp://en.wikipedia.org/wiki/Tractatus_Logico-Philosophicus
