Abstract: What is liberty, and why is it important? Why do we care about it? The first premise that I offer here is that liberty is an expression of what is valuable about us as human beings. It is a natural law idea; that is to say, it is a moral imperative based on what is fundamental (another moral idea) about our human nature. (1) I would say that what is important about us, what makes us moral human beings, is our individual capacities to think, reason, choose, and value. It is what Kant called our freedom and rationality. (2) Individuals, therefore, are the elementary particles of moral discourse. Our value is our taking individual responsibility for our lives, and our choices. And if a person is to count as a person--and here we have the difficult questions about the beginning and the end of life--then we are all equally valuable in this same way. It is from that base of our equal responsibility for ourselves that we choose our goods: that we choose what to make of the only life we will ever have. My liberty, then, is my ability to choose that life. No one has the right to interfere with that choice, except as it is to further his own good. But that good of the other is worth no more than mine because he is not worth any more than I am. There is, therefore, a right of mutual noninterference: an equal right. By the same token, nobody can interfere with or draft another person to help him achieve his own good if the other person has not chosen voluntarily to enlist in that campaign. There are conclusions to be drawn from these postulates; for example, that liberty is a relation among persons. Liberty is violated when someone else interferes with it. Gravity, tigers, and disease do not interfere with my liberty; other people do. In addition, I can make your good, that which you choose, part of my good. But then I must work through you, through your liberty, and not upon you, not in spite of your liberty. And what is interference? It can be hindering you for your sake, for your good. Or hindering you for my sake, for my good. When do I hinder you in that second sense; when do I hinder you for my sake? There are two ways. First, when I disregard you. Second, when I use you, as when I trick you or threaten you or force you in some way or another. The issue of hindering others by disregard is, in fact, conceptually the most difficult. It is pretty easy to tell when I hinder you in the second sense: when I use you, when I trick you, when I force you. These are clear-cut violations of liberty. But, how can we tell when I am hindering you by, for instance, just failing to help you, by just disregarding you? The picture I have is of my driving down the middle of the highway at eighty miles per hour, disregarding that you are coming the other way. Am I hindering your liberty, or does your demand that I regard you hinder mine? It is out of this dilemma--this dilemma of when do we hinder each other by disregarding each other, just going our way, running over each other--that we derive, in a very general sense, the concept of property. Which is why property is so closely related to liberty. (3) Property describes the whole--I will call it the n-dimensional space, as it is much more than three-dimensional--n-dimensional space in which I may operate as a free person without being hindered by you as you go about in pursuit of your goods. You may not violate my property, you may not enter my n-dimensional space. But that n-dimensional space must be defined somehow. Is it defined by liberty itself, or is it conventional, or is it a little bit of each? If it is conventional, if our property in ourselves and our property in the outside world which we have assimilated to ourselves is wholly conventional, then of course its boundaries are established by convention. If it is the creature of convention, it is the creature of others. And that is a serious problem for liberty and one which the friends of liberty have sought many ways to solve--the social contract tradition is such an attempt--and the enemies of liberty have sought to exploit from the very beginning. …