Intuitively, I believe I know a right-violation when I see one. Yet when I try to put this into an abstract universal principle, I'm not all that certain anymore. I know that rights are violated when force is initiated - and I know that my right to swing my fist ends naturally where your nose begins. Yet those are a little fuzzy. None seem to actually sharply delimit rights.
To clarify further what I'm asking for, let me tell you in what situation I usually run into this problem: when I try to explain my political views. Specifically, I run up against people who believe that my conception of "rights" implies a free-for-all Hobbesian state of nature, where whim (i.e. might) makes right. I could answer that no, in fact, whim or might does not make right, that no one has the "right" to violate somebody else's rights, but that seems like circular logic: You have the right to do whatever doesn't violate the rights of others.
I have an inkling that a proper principle would involve tying back to the right to live and moving onward from there to determine whether any of its corrolaries, like property, have been violated - but I'm still quite fuzzy on how exactly to put this in a definite principle. I hope somebody can help!
This is a big, tricky area, but I hope the following brief sketch of connections can help (of course you would need to flesh out and ground/explain all of this to someone unfamiliar with the ideas).
We humans are the rational animal, the conceptual animal, the volitional animal. That is, our fundamental means of survival is thinking (a volitional undertaking). This means that we who wish to live must seek to gasp the facts of reality and then act accordingly to further our lives. Objectivists call that rationality, our basic moral virtue.
The opposite would be our basic moral vice: evasion. Morality is for guiding us in the pursuit of life, and purposefully keeping oneself from grasping facts sabotages that process at the very root.
And this is why Objectivists consider the initiation of physical force to be our fundamental social evil. Such coercion is akin to making someone else evade: initiating physical force against someone prevents them from exercising their basic virtue of rationality, by severing the connection between their grasp of the facts and the resulting action they would otherwise take were they not being coerced. Or in a more compact form: coercing someone suppresses their moral agency and prevents their pursuit of life.
The goal of a proper government is to secure individual rights, thereby establishing the conditions that leave us (all, each) free to pursue our lives. So if you aren't sure about the "edges" of peoples' rights, what you can do is look to the origin and purpose of the idea: look for suppression of moral agency. If it is really there, you should be able to identify the physical coercion, in some form, that prevents someone from acting on their own judgment.
There are two excellent topics in The Ayn Rand Lexicon on this question, one of which was linked in Greg's answer:
To determine when a right has been violated (or not), there is a key principle stated in both topics. From "Individual Rights":
A right cannot be violated except by physical force. One man cannot deprive another of his life, nor enslave him, nor forbid him to pursue his happiness, except by using force against him. Whenever a man is made to act without his own free, personal, individual, voluntary consent -- his right has been violated.(This particular excerpt comes from Ayn Rand's article, "Textbook of Americanisn," which was published in 1946 and reprinted in pamphlet form, but apparently never republished in any other, later collection.) And from "Physical Force":
Man's rights can be violated only by the use of physical force. It is only by means of physical force that one man can deprive another of his life, or enslave him, or rob him, or prevent him from pursuing his own goals, or compel him to act against his own rational judgment.The meaning of direct bodily physical force against a person doesn't present much room for conceptual confusion, except perhaps in cases like shoulder tapping, incidental bumping, or touching of any kind, even entirely friendly and socially "normal" and "accepted" casual touching. The meaning of physical force against property is a little more complicated, since it depends on the issue of who "owns" the property in question, and thus on the concept of "rightful (morally proper) ownership." All hell may tend to break lose when the subject of "indirect" physical force comes up. The topic of "Physical Force" in the Lexicon includes an excerpt on indirect physical force:
A unilateral breach of contract involves an indirect use of physical force: it consists, in essence, of one man receiving the material values, goods or services of another, then refusing to pay for them and thus keeping them by force (by mere physical possession), not by right [moral right] -- i.e., keeping them without the consent of the owner. Fraud involves a similarly indirect use of force: it consists of obtaining material values without their owner's consent, under false pretenses or false promises. Extortion is another variant of an indiriect use of force: it consists of obtaining material values, not in exchange for values, but by threat of force, violence or injury.This excerpt is from Ayn Rand's article, "The Nature of Government," published in both VOS and CUI. The original article continues:
Some of these actions are obviously criminal. Others, such as a unilateral breach of contract, may not be criminally motivated, but may be caused by irresponsibility and irrationality. Still others may be complex issues with some claim to justice on both sides....Thus, the essential elements involved in determining rights violations in complex cases are:
OPAR identifies physical force as follows (p. 310):
Physical force is coercion exercised by physical agency, such as, among many other examples, by punching a man in the face, incarcerating him, shooting him, or seizing his property. "Initiation" means starting the use of force against an innocent individual()s), one who has not himself started its use against others.As already noted, "coercion" here needs to be understood as encompassing four other issues: (a) values, (b) morally proper ownership thereof, (c) deprivation thereof, and (d) without the consent of the one deprived.
Finally, it should also be noted that philosophy cannot be a substitute for law, i.e., for the process of collecting specific data as to the details of human actions, and then identifying how the broad principles of philosophy apply (or not) to specific cases. OPAR observes (pp. 319-320):
The task of defining the many forms of physical force, direct and indirect, including all the variants of breach of contract, belongs to the field of law.