We tend to think of imagination as a distinctly human ability. But already from Roman times, philosophers pointed out that animals can dream, and that dreaming involves the imagination. Today we have evidence from neuroscience and psychology that plenty of animals re-enact scenes from waking life while asleep. Having imagination indicates that animals, beyond their capacity to sense and feel, are fully fledged subjects. This finding makes it a lot harder  to argue that animals don’t have moral rights, argues David M. Peña-Guzmán.

There is an entry in Voltaire’s Dictionnaire philosophique devoted to dreams. Written in 1764, a quadrans centennial before the eruption of the French Revolution, this entry describes dreams as cryptic experiences that have historically lived in the domain of superstition—in the stirring orations of bards (myth), the edifying homilies of priests (religion), and the speculative conjectures of philosophers (metaphysics). Although Voltaire considered himself a critic of superstition in all its forms, in this work he confesses that he understands the occultist appeal of dreams: They are complex psychic events that test the limits of human thinking, puzzles that neither materialist nor idealist philosophies have managed to solve.