Rights are often considered fundamental to civilization, for they are regarded as established pillars of society and culture, and the history of social conflicts can be found in the history of each right and its development. According to the Stanford Encyclopedia of Philosophy, "rights structure the form of governments, the content of laws, and the shape of morality as it is currently perceived".
There is considerable disagreement about what is meant precisely by the term rights. It has been used by different groups and thinkers for different purposes, with different and sometimes opposing definitions, and the precise definition of this principle, beyond having something to do with normative rules of some sort or another, is controversial.
One way to get an idea of the multiple understandings and senses of the term is to consider different ways it is used. Many diverse things are claimed as rights:
There are likewise diverse possible ways to categorize rights, such as:
Some thinkers see rights in only one sense while others accept that both senses have a measure of validity. There has been considerable philosophical debate about these senses throughout history. For example, Jeremy Bentham believed that legal rights were the essence of rights, and he denied the existence of natural rights; whereas Thomas Aquinas held that rights purported by positive law but not grounded in natural law were not properly rights at all, but only a facade or pretense of rights.
Liberty rights and claim rights are the inverse of one another: a person has a liberty right permitting him to do something only if there is no other person who has a claim right forbidding him from doing so. Likewise, if a person has a claim right against someone else, then that other person's liberty is limited. For example, a person has a liberty right to walk down a sidewalk and can decide freely whether or not to do so, since there is no obligation either to do so or to refrain from doing so. But pedestrians may have an obligation not to walk on certain lands, such as other people's private property, to which those other people have a claim right. So a person's liberty right of walking extends precisely to the point where another's claim right limits his or her freedom.