office for the president of the Liberal Democrat Party in England. The historian Peter Marshall described On Liberty as "one of the great classics of libertarian thought", due to its exaltation of individual freedoms. Contradiction to utilitarianism Mill makes it clear throughout On Liberty that he "regard[s] utility as the ultimate appeal on all ethical questions", a standard he inherited from his father, a follower of Jeremy Bentham. Though J. S. Mill claims that all of his principles on liberty appeal to the ultimate authority of utilitarianism, according to Nigel Warburton, much of the essay can seem divorced from his supposed final court of appeals. Mill seems to idealize liberty and rights at the cost of utility. For instance, Mill writes: This claim seems to go against the principle of utilitarianism, that it is permissible that one should be harmed so that the majority could benefit. Warburton argues that Mill is too optimistic about the outcome of free speech. Warburton suggests that there are situations in which it would cause more happiness to suppress truth than to permit it. For example, if a scientist discovered a comet about to kill the planet in a matter of weeks, it may cause more happiness to suppress the truth than to allow society to discover the impending danger. While David Brink concedes that Mill's apparently categorical appeal to rights seems to contradict utilitarianism, he points out that Mill does not believe rights are truly categorical because Mill opposes unrestrained liberty (e.g. offensive public exposure). Furthermore, David Brink tries to reconcile Mill's system of rights with utilitarianism in three ways: Rights are secondary principles to the Greatest Happiness Principle Rights are incomparable goods, justifying their categorical enforcement Liberty is a good. Thus, those who suppress it are worthy of punishment. Rights deal with the value of punishing/protecting others' interference with liberty, not the actual protection of liberty Narrow focus Some thinkers have criticised Mill's writing for its apparent narrow or unclear focus in several areas. Mill makes clear that he only considers adults in his writing, failing to account for how irrational members of society, such as children, ought to be treated. Yet Mill's theory relies upon the proper upbringing of children. Plank has asserted that Mill fails to account for physical harm, solely concerning himself with spiritual wellbeing. He also argues that, while much of Mill's theory depends upon a distinction between private