moral philosophy 
noun [mass noun]
The branch of philosophy concerned with ethics.It is moral philosophy that ‘makes philosophers, and purifying their understanding, makes them capable of considering the wonders of nature’....
- In Kant's enormously influential moral philosophy, autonomy, or freedom from the causal determinism of nature, became prominent in justifying the human use of animals.
- Kant's moral philosophy emerges from the amalgamation of the idea of transcendental freedom with that of an imperative of reason.