"The scientific course is to put the burden of proof on the attribution. As a scientist, you can't just declare, for instance, that the presence of glutamate molecules amounts to the presence of mind; you have to prove it, against a background in which the "null hypothesis" is that mind is not present. There is substantial disagreement among scientists as to which species have what sorts of mind, but even those scientists who are the most ardent champions of consciousness in animals accept this burden of proof—and think they can meet it, by devising and confirming theories that show which animals are conscious. But no such theories are yet confirmed, and in the meantime we can appreciate the discomfort of those who see this agnostic, wait-and-see policy as jeopardizing the moral status of creatures that they are sure are conscious."