It is a bitter thought, how different a thing the Christianity of the world might have been, if the Christian faith had been adopted as the religion of the empire under the auspices of Marcus Aurelius instead of those of Constantine.

During his time as an MP Mill advocated easing the burdens on Ireland. In 1866 Mill became the first person in the history of Parliament to call for women to be given the right to vote vigorously defending this position in subsequent debate. And as most opinions are neither completely true nor completely false he points out that allowing free expression allows the airing of competing views as a way to preserve partial truth in various opinions.

He was a proponent of utilitarianism an ethical theory developed by Jeremy Bentham. Mill's conception of liberty justified the freedom of the individual in opposition to unlimited state control.