This is an unusual book, both in content and in style. In content it is about logic, though Ludwig Wittgenstein, in discussing this subject, manages to say much about the theory of signs, epistemology, metaphysics, and philosophy in general. Furthermore, Wittgenstein indicates that there are many things that we cannot say about logic, not because we do not know them or because we cannot find words by which to express them, but because they are literally inexpressible by means of any language. Consequently, we must remain silent about them.
The sentences (or sometimes groups of sentences) in this work are all numbered in accordance with a plan. For example, a certain sentence has the number 3; this follows sentences 1 and 2 in the order of the natural numbers. However, between 2 and 3 are sentences numbered, for example, 2.0122 and 2.151. Sentence 2.0122 is a statement referring to statement 2. Statement 2.151 follows statement 2.1 and is a comment on it; statement 2.1, in turn, is another comment on 2, and follows it. All statements are in this way arranged in a unique, linear order based on the decimal notation, and the reader is able to determine by the number attached to each sentence what general topic is being considered, what special aspect of this general subject is involved, and so on, sometimes to a fourth level of specialization.
Furthermore, because of the unusual meanings associated with many of the terms employed by the author, the editor chose to publish, on facing pages, the original German text and its parallel English translation. This design permits those who are familiar with German to improve their understanding of the text by comparing the English version with its German original, thereby in many cases detecting fine shades of meaning. In a book where such common words as “fact,” “object,” “meaning,” and “truth” occur in great abundance and are employed with somewhat unusual connotations, the parallel translation is of great help. The book also contains a valuable introduction, written by Wittgenstein’s mentor Bertrand Russell, that both summarizes the text and criticizes it on some important points.