Admissions of failure are part of philosophy

Very hard to be taken seriously as a philosopher if you don't admit your mistakes.

Robert Nozick was an American philosopher who wrote on every subject he could get his hands on. He is well known for his lone venture into political philosophy; Anarchy, State, and Utopia. In that book, he argues for a minimalist state that never infringes on personal liberties. At one point, he even muses over how an income tax is akin to part-time slavery, as a worker is paid in wages and a part of them are given to the state without the chance to opt out. His ideal state wouldn’t have any taxation.

His adjustments to his earlier stances are subtle but notable. He doesn’t fundamentally change his position but rather admits problems with it. He endorses the idea that the state can ban discrimination against various groups, admits that the realization of personal freedom may require mandated group effort, and yields to the use of taxation or mandated donation to specific charities as a means to assure society continues to function. While in later interviews he assured readers that he had not abandoned libertarianism, he took the edge off a few of the more hard-line views as he aged.

http://bigthink.com/scotty-hendricks/four-philosophers-who-realized-they-were-completely-wrong