Such is the facility with which mankind believe at one and the same time things inconsistent with one another, and so few are those who draw from what they receive as truths, any consequences but those recommended to them by their feelings, that multitudes have held the undoubting belief in an Omnipotent Author of Hell, and have nevertheless identified that being with the one best conception they were able to form of perfect goodness.

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.