When it comes to justice, humanity is in a state of flux. On the upside, world poverty and malnutrition have fallen since the turn of the century; average life expectancies and literacy rates have risen. On the downside, extremes of wealth and poverty have grown wider, civil strife, terrorism and gun violence have spiralled. Governments have responded by side-lining human rights - from China's crackdown on Uighurs to military repression in Egypt and the bloody battle for Syria. Here, Professor Raymond Wacks breaks down leading theories of justice to illustrate how present-day challenges affect our fundamental notions of fairness and freedom.