A sentient being is one that has sensations and perceptions. So any living thing that is conscious could be called sentient. Of course, since we can’t know for sure how nonhuman animals think and feel, sentience is open to interpretation. Human chauvinists might claim only humans are sentient. Others might claim only mammals are sentient, or only animals with eyes, or only animals with locomotion.
These interpretations can have huge philosophical and ethical implications. To describe an animal as sentient usually implies it has some inherent value as a living being. So, for instance, if you feel all mammals and birds are sentient but fish are not, this may guide your dietary choices.
But we won’t go into all the philosophical issues here. Let’s just look at some recent examples of the word in action:
Once dismissed by science as insentient beings, animals are now increasingly viewed as sentient, feeling individuals with a right to life and personal dignity. [New York Times]
Rugby players have thought processes now? So, why do they look about as sentient as a tumble dryer? [Irish Times]
Look into the eyes of a cow and you will see most of the same sentient responses as we see in a fellow human being. [Australian]
Your average sentient human chooses to endure only one Lions game per year, on Thanksgiving. [Wall Street Journal]
Kibwe Tavares’ short film “Robots of Brixton” imagines a world where sentient machines are given inhuman treatment by humans. [Salon]
Sentient seems most common in American publications. Good examples from outside the U.S. are hard to find. We can’t explain this.