OK, I know this issue has been discussed extensively. However, I think it is one of the most confusing issues for libertarians, I know it was for me. If any of you know of someone that has already explained rights in this way, please let me know.
There are three categories of creatures I want to discuss. First, is the adult human. Next is the animal. And last is the infant/child human.
The key question, is how do we know that someone has been wronged? There are two criteria. First, we know that someone has been wronged if he or she did not consent to something and someone acted against him or her anyways. For example, I do not know of anyone that would disagree that theft, rape, and murder are all wrong. So what makes them wrong? The reason is because they all imply a lack of consent. Theft is not wrong because someone took something from another person. It is wrong because someone took something from someone else without valid permission (holding a gun to someone’s head and “asking” for something is not valid permission). Rape is not wrong because someone had sex with someone else. Rape is wrong because someone had sex with someone else without consent. And same with murder. The reason it is wrong is not because someone killed another person, but because someone killed another person without consent. So, I think it is pretty conclusive that if consent is not granted, then a wrong has been committed.
But that leads us to animals. If not getting consent means a wrong has been committed, then killing an animal, having sex with an animal, or taking an animals property would all be wrong as well. This presents a conundrum however, for animal rights activists. How should carnivores be treated for killing other animals? How should males be treated for forcing sex onto females in their own species? How can humans reconcile the problems of animal property rights? So obviously, just lack of consent is not the only criteria for determining if a being has been wronged. The other criteria is if another being has the ability to consent, and then withholds consent. The reason animals do not have rights is because even though they do not grant consent, they do not have the mental ability in the first place of granting consent. So, the two criteria in determining whether or not a being has been wronged is that the being in question has the ability to grant consent in the first place, and in the second place did not grant consent.
This leads us to infants and small human children. They have the ability to withhold consent, however they do not have the mental ability to grant consent. Given that they do not have the ability to grant consent, they do not have rights. Now, one may ask “at what point in time do humans gain the ability to grant consent”? Well this is a question best left up to judges and child psychologists. Now, someone that believes that children have rights may say that this is completely arbitrary. But even someone that believes children have rights will have to concede that at some arbitrary point in life, it is all of a sudden OK to have sex with a human or for them to sell things and it not considered theft. However, children do not have rights, because as has already been established, they do not have the mental ability to grant consent. This is also why people in a coma do not have rights, since they no longer have the mental ability to grant consent. I am not a psychologist, so I do not know all the mental abilities of mentally handicapped people, but I would guess they do have some limited abilities to grant consent, if not full abilities, and as such probably have rights.