I was listening to the radio a few days ago and heard Janis Joplin's "Me and Bobby McGee", which contains the famous line: Freedom's just another word for nothin' left to lose. It got me thinking.
Basically, I think she's right. Taking an overly-analytical approach, suppose you did have something to lose. Then you could be threatened by its loss, and such threats might cause you to change your behavior. If someone else can force a change in your behavior, then you are not free. You might be mostly free, but not completely free.
You might object that the things you could lose might be of very small value, but this doesn't save your freedom. While you might not change your behavior on something big when threatened by the loss of something of small value, some small behavior change could still be forced as long as you had something to lose. Indeed, I would argue that these conditions are identical: if you would not change your behavior in any way, however slight, to protect a thing, then that thing must have no value to you.
There is still, though, a possible escape. Suppose you had things to lose, but they were so arranged that the loss of any of them would result in a larger gain elsewhere. I can't imagine in practice how this would work, but if it did, you could theoretically have something to lose but would be willing to lose it. Still, in practice if you could exchange something of smaller value for something of larger, wouldn't you do it before the appearance of a threat? So I won't worry about this theoretical case.
However, imagine that you truly have nothing to lose. Is such an existence desirable? As I have argued above, having nothing to lose implies valuing nothing. You would not be able to have friends. Possessions, of course, would be out. You could not make a stand "on principle". This seems highly undesirable. In a sense it's akin to Nirvana, but the Buddhist ideal is more extinguishing the "negative" emotions of greed, anger, and so on. One who valued absolutely nothing would also have to extinguish positive emotions like love and compassion.
There is a logical problem that appears here as well: complete freedom should mean having the freedom to acquire things, or make friends. But then you would not be free, or at least would risk starting to value something and thus losing your perfectly free state. So it is questionable whether the sort of complete freedom we contemplate here is even achievable.
Putting that aside for the moment and stipulating that the logical paradox does not arise, it seems clear that almost no one would be happy being entirely free in the sense I have described. We "voluntarily" accept chains to the things we value. I added the scare quotes because it's a bit slippery what we mean by "voluntary" here. It's clearly not entirely voluntary: having valued something, we open ourselves to its possible loss, and thus to a possible loss of freedom. But the actual curtailment of our freedom might never occur; it might only be imposed from the outside in the form of threats, which may never materialize. (In practice, many of the threatened losses are inevitable conflicts between things we already value, and thus are not imposed by an outside party.)
In a sense, then, freedom is the freedom to choose our chains.