What does Thoreau mean when he says that "any man more right than his neighbors constitutes a majority of one already?"
Thoreau's central argument in Civil Disobedience is that when the laws of the state conflict with a higher moral law, it is the moral responsibility of the individual to obey the higher law. This may be seen as conflicting with the democratic principle of majority rule, however, in which the laws of the state are established with the consent of the majority. With this statement, Thoreau is claiming that individual conscience is supreme, and that a moral society can only exist when individuals are willing to violate civil law, or, in his words, to let their lives be "a counter friction to stop the machine." This was because the state was often incompetent to end such systemic evils. The best a person can do is to live by their own moral code:
What I have to do is to see, at any rate, that I do not lend myself to the wrong which I condemn. As for adopting the ways which the State has provided for remedying the evil, I know not of such ways. They take too much time, and a man's life will be gone.
For Thoreau, civil disobedience took the form of refusing to pay taxes on the grounds that he was opposed to American participation in the Mexican War.