René Descartes’s dog, Monsieur Grat (‘Mister Scratch’), used to accompany the 17th-century French philosopher on his ruminative walks, and was the object of his fond attention. Yet, for the most part, Descartes did not think very highly of the inner life of nonhuman animals. ‘[T]he reason why animals do not speak as we do is not that they lack the organs but that they have no thoughts,’ Descartes wrote in a letter in 1646.

Followers of Descartes have argued that consciousness is a uniquely human attribute, perhaps facilitated by language, that allows us to communicate and coordinate our memories, sensations and plans over time. On this view, versions of which persist in some quarters today, nonhuman animals are little more than clever automata with a toolkit of preprogrammed behaviours that respond to specific triggers.

(continue reading)