Nico Frijda writes that emotions are governed by a psychological principle called the "law of apparent reality": emotions are elicited only by events appraised as real, and the intensity of these emotions corresponds to the degree to which these events are appraised as real. This observation seems psychologically plausible, but emotional responses elicited by works of art raise counterexamples. Frijda's law accounts for my panic if I am afraid of snakes and see an object I correctly appraise as a rattlesnake, and also for my identical response if I see a coiled garden hose I mistakenly perceive to be a snake. However, suppose I am watching a movie and see a snake gliding toward its victim. Surely I might experience the same emotions of panic and distress, though I know the snake is not real. These responses extend even to phenomena not conventionally accepted as real. A movie about ghosts, for example, may be terrifying to all viewers, even those who firmly reject the possibility of ghosts, but this is not because viewers are confusing cinematic depiction with reality. Moreover, I can feel strong emotions in response to objects of art that are interpretations, rather than representations, of reality: I am moved by Mozart's Requiem, but I know that I am not at a real funeral. However, if Frijda's law is to explain all emotional reactions, there should be no emotional response at all to aesthetic objects or events, because we know they are not real in the way a living rattlesnake is real. Most psychologists, perplexed by the feelings they acknowledge are aroused by aesthetic experience, have claimed that these emotions are genuine, but different in kind from nonaesthetic emotions. This, however, is a descriptive distinction rather than an empirical observation and consequently lacks explanatory value. On the other hand, Gombrich argues that emotional responses to art are ersatz; art triggers remembrances of previously experienced emotions. These debates have prompted the psychologist Radford to argue that people do experience real melancholy or joy in responding to art, but that these are irrational responses precisely because people know they are reacting to illusory stimuli. Frijda's law does not help us to untangle these positions, since it simply implies that events we recognize as being represented rather than real cannot elicit emotion in the first place. Frijda does suggest that a vivid imagination has "properties of reality" – implying, without explanation, that we make aesthetic objects or events "real" in the act of experiencing them. However, as Scruton argues, a necessary characteristic of the imaginative construction that can occur in an emotional response to art is that the person knows he or she is pretending. This is what distinguishes imagination from psychotic fantasy.