The thinker, because he is a thinker, cannot naively live his life of thought, but must be tormented by doubts regarding it. The doer, because he is not a thinker, can naively live his life of action.
And which is the philosopher? The doer or the thinker? The philosopher is neither; the philosopher is the man who unites thought and deed; the one who "understands the abstract concretely." (Kierkegaard) At least he was once understood thus.
The ancient philosophers were not tormented by doubts about their lives, because they had not yet separated thought and deed in the modern fashion. For the ancient philosopher, thought was a deed, which was why the Socratic cross-examination was a fruitful method of philosophical investigation. To force a man into a contradiction was to force a change in his life, because men lived immediately in their thought. Today, we are not bothered by contradictions, since our thought bears no necessary connection to our lives. The intellectual, the man who manages to live serenely while advocating an array of bizarre and self-contradictory doctrines, is a peculiarly modern phenomena.
Philosophy is held in such ill-repute today because, once the separation between thought and life is made, the penalty of contradiction disappears. The critics are then quite justified in dismissing philosophy as a gassy exchange of opinions from which nothing decisive can emerge. If philosophy is to be renewed, it will only be by thought and life being reunited.