It could be argued that we know babies will soon attain a language and, therefore, should be granted moral rights. It is wishful thinking to expect some miracle that would allow them to speak again. However, it could be argued that moral rights should not be taken from them simply because an accident has deprived them of communication. 127-9 humans also have moral duties. Raphael claims that humans and animals both have moral rights.
Humans also have moral duties because of their ability to reason and speak.
Animals have rights but not duties. It could then be argued that babies and mentally deficient people have rights but not duties. Children acquire duties only when they attain the reason to understand duty. However, Raphael does not explain why animals have rights alongside humans. It could be argued that moral right and duty go together and we cannot have one without the other.