Evolving Perspectives on Sentience in Invertebrates

Sentience is a puzzle - and an increasingly important one. The question of exactly what constitutes sentience, and which organisms possess it, is hotly contested. But with scientific evidence emerging in support of the theory that octopuses, bees and other invertebrates may be sentience candidates, moral questions of how we should treat them become more and more pressing. And then there's AI - could sentient robots be on the horizon?