Morality generally involves discussion of rights, duties, and responsibility. Animal rights advocates argue that at least some animals fall within the domain of the moral universe and that human practices such as animal experimentation and factory farming are subject to moral limits. In respect to personhood, there are three categories that emerge from any philosophical analysis. There are undoubted persons, undoubted non-persons, and hard cases . Today, with a few exceptions all living human beings are generally considered to be undoubted persons , in the sense that we agree that we ought to consider how our actions affect each other.
All human beings have both rights and duties.
There are also undoubted non-persons , like my electric guitar, that obviously have no rights or duties. Today philosophers acknowledge hard cases , a third class of entities that we debate. Since the 1970s, we've been debating the personhood of animals , eco-systems, fetuses, and comatose human beings. There are several different possible approaches to this task of differentiating persons from non-persons. We might argue that all persons have the capacity to claim certain rights.