Externalism in philosophy of perception and argument(s) from dreaming

A recurrent pattern of debate between the proponents of internalism and externalism over mental phenomena is as follows: externalists pick a target mental phenomenon, say, visual perception, and argue that it has the characteristics it has because of a property that is not possessed internally. Internalists, in return, substitute an analogue mental phenomenon, one that putatively suits their position, to argue that it shows every characteristic that the original target phenomenon shows, thus the allegedly crucial external property plays no ineliminable role. Within these debates a particular analogue phenomenon frequently appears: dreaming. In what follows, I discuss the ways in which externalism comes under dispute through dream phenomena. I then investigate the scientific literature to evaluate whether the way dreaming is conceived by internalists is substantiated by the available body of evidence. I conclude that the current state of sleep science does not lend support to internalists’ conception of dreaming.