Although it is notable to point out that Nietzsche eventually lost his sanity before the turn of the century, his writings were nonetheless influential in bringing change to modern philosophical thinking, and in contributing to an overall sense of uncertainty in the years after World War One.
Following in the revolutionary footsteps that Nietzsche laid out in world of philosophical thinking, were two equally, if not more influential ideas called logical empiricism (or logical positivism), and existentialism. The origins of logical positivism can be traced to a philosopher named Ludwig Wittgenstein. He argued that philosophy deals only in the realm of logical thoughts, and that since thought is expressed through language, true philosophy should deal with the study of language. Issues such as religion or God, morality, and human freedoms were in his opinion not worth pondering about. If a certain subject matter could not be observed or demonstrated in a logical manner, or be proven or tested scientifically, they were said to exist in the scope of personal opinions and therefore had no importance in philosophical matters. The limitations that logical positivism created meant that people could no longer confide in philosophy for answers to their feelings of personal anxiety and uncertainty, thus fueling this fire and increasing people's disillusionment. .
In response to all of this uncertainty and anxiety another form of philosophical thinking emerged called existentialism. It attempted to cope with all of these feelings by recognizing that there is uncertainty inherent in humans to begin with. Most of its followers do not believe in God, and their viewpoint is that humans are alone in the universe with no higher being present that can help them through all the trials and tribulations of life on earth. The concerns of the existentialist thinker are the same as those suffering in the Age of Anxiety.
