Book excerpt: We live in an age of ideology, propaganda, and tribalism. Political conformity is enforced from many sides; the insidious social control that John Stuart Mill called “the tyranny of the prevailing opinion and feeling.” Liberal or left-minded people are often more afraid of each other than of their conservative or right wing opponents. Social media and call-out-culture makes it easier to name, shame, ostracize and harass non-conformists, and destroys careers and lives. How can we oppose this, regaining freedom and our sense of ourselves as individuals? The Tyranny of Opinion identifies the problem, defines its character, and proposes strategies of resistance. Russell Blackford calls for an end to ideological purity policing and for recommitment to the foundational liberal values of individual liberty and spontaneity, free inquiry, diverse opinion, and honest debate.