The sense of justice is continuous with the love of mankind.
Ideal legislators do not vote their interests.
The bad man desires arbitrary power. What moves the evil man is the love of injustice.
Clearly when the liberties are left unrestricted they collide with one another.
Certainly it is wrong to be cruel to animals and the destruction of a whole species can be a great evil. The capacity for feelings of pleasure and pain and for the form of life of which animals are capable clearly impose duties of compassion and humanity in their case.
The idea of public reason isn't about the right answers to all these questions, but about the kinds of reasons that they ought to be answered by.