Definition of "sentience"

For a while I sat quiet, my heart beating. The place was grimly dark. The only light was a faint one from the top of the lamp which threw a white circle on the high ceiling, except the emerald sheen of the shade as the light took its under edges. Even the light only seemed to emphasize the blackness of the shadows. These presently began to seem, as on last night, to have a sentience of their own.

1903, Bram Stoker, chapter 5, in The Jewel of Seven Stars

The science of animal sentience is far from a firm one; there's no way of knowing exactly what any animal is feeling.

2007 December 28, Alexandra Silver, “Did This Tiger Hold a Grudge?”, in Time‎, archived from the original on 20 April 2010