In George Bernard Shaw's play Major Barbara, the quote "He knows nothing; and he thinks he knows everything. That points clearly to a political career" reflects the themes of ignorance and confidence in political figures. It suggests that individuals who occupy positions of power often possess a misguided sense of their own knowledge and capabilities, which can result in misguided decisions and policies. This idea resonates with the public's perception of politicians who may be out of touch with reality.

The statement also critiques the nature of political ambition, wherein self-assuredness can overshadow genuine understanding and expertise. Shaw's commentary implies that such traits are not just common but almost a prerequisite for entering politics, leading to a disconnect between leaders and the populace. Through this lens, Shaw invites readers to reconsider the qualities that constitute effective leadership and the dangers of misplaced confidence in governance.