Wittgenstein

Wittgenstein was born into a rich Austrian family of Jewish descent in 1889.
His father was a millionaire who had 9 children and raised them all as catholics.
Wittgenstein himself lost his faith in school, this is perhaps due to Schopenhauer's influence.
He studied engineering in Berlin and then at the University of Manchester, in which he (impressively) designed a jet reaction engine.

He became acquainted with the works of Frege whom he visited in 1911, and on his advice, went to Cambridge and studied under Russell for the next 5 years.
In 1913, Wittgenstein went to Norway to live solitarily in a hut he had built himself, in which he began developing his philosophical ideas. One of which was the idea that philosophy cannot confirm or confute scientific investigations.

In 1914 War broke out and Wittgenstein went to volunteer in the Austrian artillery. Unfortunately he was captured by Italian soldiers in 1918 and sent to prison camp. It was here that he turned his philosophical diary into "Tractatus Logico Philosophicus" which he sent to Russell and it was published in 1921.

 The work is described as "short, beautiful and cryptic". The first chapter is the sentence "the world is all that is the case", and the last is "whereof one cannot speak, thereof one must remain silent". In essence he comes to the conclusion that if one is not familiar with the facts surrounding a matter, one should remain silent. This is not unsimiliar to Socrates' famous quote: "And in knowing that you know nothing, that makes you the smartest of all."

Wittgenstein's picture theory of propositions states that  propositions can represent reality by making a logical picture of the facts they represent.  A picture must have something in common with what it depicts.According to Wittgenstein, this is a common logical form. Therefore, a  proposition has the same logical form as the fact it represents.  Words in a proposition do not resemble facts in the actual world, but we can recognise one as the picture of another through the common logical form.

The text also  deals with Logical Atonism, which is inspired by Russell. It is the idea that the world can be repeatedly be analysed into simple, incorrigible facts. For example, fact A can be simplified multiple times until it can no longer be reduced. It can no longer be reduced when it reaches the terminus of objects, which Wittgenstein describes as "logical forms without content".

Philosophy according to him is not a theory but rather an activity. This activity is to clarify non-philosophical propositions.This idea formed the basis of the Vienna Circle's ideologies. 

According to him,  neither science, nor philosophy can reveal  the meaning of life to us, but what philosophy can do for us, according to Wittgenstein, has been fulfilled by Tractatus. H believed this so much so, that after it was published, Wittgenstein gave up philosophy and supported himself by doing various odd jobs. in 1926, his teaching career came to a halt when he was accused of sadistic punishment by a student.

Wittgenstein states that if the reader has got a full understanding of  the Tractatus, he will regard it as nonsense. He compares it to a ladder which we have climbed and now can throw away. Essentially, he is asking us reconsider everything that we have read,  because we have understood his main message which is "the world is NOT  all that is the case".  This idea somewhat contradicts his message that the Tractatus gives us all that philosophy has to offer. Although perhaps he is stating that the book tells us that the world is not totally of facts, and that is as close to the truth as we can get.