John Stuart Mill was born in May 1806 and died in May 1873. There's a long appreciation here by Richard Reeves, who describes Mill as 'the most eloquent advocate of human freedom ever to write in the English language':
Mill made, in his famous On Liberty, a timeless case for freedom of speech and action that has inspired generation after generation around the world... [A]s an elderly MP he also led the successful campaign against Disraeli's attempt to ban demonstrations in public parks, especially Hyde park - a corner of which remains a symbol of free speech to this day.
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Mill insists that religion should be subject to the same criticism as any other system of thought, regardless of the offence caused. I think we can be confident that Mill would be disappointed by the progress made on this issue in the last century and a half, and by the regress of the last half decade.