If I am obliged not to do any harm to my fellow man, it is less because he is a rational being than because he is a sentient being.
Gist of Idea
If we should not mistreat humans, it is mainly because of sentience, not rationality
Jean-Jacques Rousseau (Discourse on the Origin of Inequality , Pref)
How should sentience and rationality be weighted here? Kant demands instrinsic respect for beings on the grounds of their rationality. What could ever justify doing needless harm to anything? An open goal for virtue theory here.
Rousseau,Jean-Jacques: 'The Basic Political Writings', ed/tr. Cress,Donald A. [Hackett 1987], p.36