But then there is a need to define liberty. And I am afraid I won’t do a great job even if I try.
The main problem with authority is that it springs from something. It either springs from money or physical strength or sometimes just “custom” and therefore authority is not the natural state of things. Liberty is the natural state of things.
You are, somewhat, alone in this world and everything else is just perception. Note that Descartes with his foundationalism only established the belief in self and that was the only certain belief he had. The rest was all derived. Hence, your natural state is liberty. Man is free.
Authority restricts and controls. Liberty allows man what he deserves. Liberty allows maximum learning and allows maximum progress. Authority can restrict all this so there should be no authority at individual level. As soon as a person is 18 he should be free to do whatever he wants to and however he wants to.
Authority has a role to play too. Authority comes in for the economic distribution. This authority needs to come from the major part of the liberal population. And the purpose of this authority is to distribute wealth equally. This is important to maintain equality because equality is going to maintain liberty at individual level. If there is no authority of this sort we will have serious social classes and a lot of authority issues.
An 18 year old needs to be free. His parents should not have to pay for his expenditure. He should step into the free world, earn and live at his own expense. This system will work towards a classless society. Families will not accumulate wealth for their children. The money you earn goes to the state once you die. The state authority makes sure your wealth is distributed amongst the lowest-earning people in order to work towards equality. There is going to be no point accumulating wealth because you can’t take it with you once you are dead and your children don’t get it either if they are doing fine on their own. This is the extent of individual liberty that I support.
So it IS YOUR MORAL DUTY, towards your society, to be free.