Sentience is such an over-hyped and exaggeratec concept that people get very angry when you try and understand/explain it.
Everything we think/do/feel (including sentience) is a result of the electrochemical activity in our neural networks. The networks are very very complicated which means that the variety and intensity of our throughts/actions/feelings are also equally, if not more, complicated. But in the end the mind is just the activity of the brain. There is no magical spirit or soul or anything else.
We're machines ... very complicated machines ... but machines nonetheless. This label of consciousness or sentience that we often use will not magically transform us into anything else.
Here are a few of the many many many myths surrounding this topic at the moment.
It may be upsetting to think of ourselves as glorified gears and springs. Machines are insensate, built to be used, and disposable; humans are sentient, possessing of dignity and rights, and infinitely precious. A machine has some workaday purpose, such as grinding grain or sharpening pencils; a human being has higher purposes, such as love, worship, good works, and the creation of knowledge and beauty. The behavior of machines is determined by the ineluctable laws of physics and chemistry; the behavior of people is freely chosen. With choice comes freedom, and therefore optimism about our possibilities for the future. With choice also comes responsibility, which allows us to hold people accountable for their actions. And of course if the mind is separate from the body, it can continue to exist when the body breaks down, and our thoughts and pleasures will not someday be snuffed out forever.
Sad wishful thinking. I personally am proud of what I am and dont need to delude myself in order to feel so.