Level of Relevancy

In response to Sebastian's post 'What gives animals Legal Rights?' (4/21/2013):

While I agree that autonomy alone is not a valid basis for deciding which animals have which rights, I think that it does have some place in the list of factors.  If a being is not autonomous, then it may actually benefit from being controlled in some way or ways, and probably does not have a sense of liberty versus oppression.  At the end of the post I am replying to, Sebastian suggested that autonomy is no more morally relevant than race, gender, or age - the first two are most certainly morally irrelevant, but the last is not, and may provide a helpful comparison.

Children are not typically able to survive without the aid of adults, and so the law gives them certain rights that adults do not have - for example, the right to be cared for.  For the same reasons, they are deprived of other rights, such as the right to vote.  The rationale for this is that if children possessed those rights, it would harm either the children themselves, the society as a whole, or something else of value. The basis upon which this distinction between children and adults rests is composed of many different factors, only one of which is age.  If the only difference between children and adults was their age, and the experience which comes with it, there would be far less justification for granting them different legal rights.

Similarly, I think that autonomy plays an important part in determining which rights belong to which animals.  So do intelligence level, social or solo nature, longevity, physical features, and many other factors.  I do not think that one factor alone can provide a morally relevant distinction between any two categories of being.