Reasoning relies on establishing the truth of statements, which can then be used to build up a train of thought leading to a conclusion and philosophy cover this idea of constructing a rational argument. It means, philosophy is not so much about coming up with the answers to fundamental questions as it is about the process of trying to find these answers, using reasoning rather than accepting without question conventional views or traditional authority.
Now, problem is philosophical logic unlike mathematics, is expressed in words rather than numbers or symbols which is subject to all the ambiguities and subtleties inherent in language. Thus, understanding and examine the language we use in construction of reasoned argument is important beside the logic itself. This requirement has been created "philosophy of language" in 20th century.
A brief to philosphy of logic and language which I am going to love!