LibertyLiberty has always been a very difficult political term to define. Basically, its meaning would be that people (or whatever subsystem is to be free) are able to choose themselves goals they will achieve.
Thinkers soon discovered that paradoxically, while physical constraints, like violence, directly opposed liberty, moral constraints (as expressed through laws), are an essential condition for any liberty to exist. Actually, this paradox has an easy solution, once settled a proper theory for liberty.
We define liberty as potential information. Security will be actual information. Physical constraints yields a little original information (most being redundant), while wasting a great lot of resources, which is why they reduce liberty so much. Moral constraints, on the other hand, allow the willing man to focus on a restriction of the system where the world has a meaning, that is, information, so that any new input from the world will be additional information; thus moral constraints do increase liberty. More, with physical constraints, people reduce each other's liberty, while with moral constraints, people increase each other's liberty. In the first case, people expect each other to negatively interfere with each other's goals. In the second case, people can expect each other not to.
For example, having people repeat endlessly the same sentences of wisdom greatly reduces their liberty, and the more wisdom is being repeated, the more their liberty is reduced: by repeating endlessly, one wastes the limited available resources one can dispose of, thus depriving potential information from being made available with these resources; worse even, just repeating things makes those things meaningless, however great their original meaning was, because they do not confront to reality anymore. Information comes from interaction, not just sitting there. So not only is liberty reduced, but the security is small (because of redundancy) and illusory.
But on the other hand, defining lots of rules about the meaning of sentences greatly increases liberty, by letting people communicate more easily, thus allowing to convey lots of information that couldn't be possible otherwise.
John Stuart Mill has written the excellent essay "On Liberty" (1859), which I recommend to everyone. It will explain much better than we may what liberty is, at least what we think about it in the TUNES project.
Because of a natural tendency toward entropy, liberty naturally decreases, and we need continuously fight for it not to eventually reduce to nothing.