The absence of belief that accompanies imagination is a somewhat sophisticated product; it fails in sleep and in strong and emotional excitement. Children invent terrors for fun, and then begin to believe in them. The state of entertaining an idea without believing it is one involving some tension, which demands a certain level of intellectual development. It may be assumed that imagination, at first, always involved belief, as it still does in dreams. I am not concerned at the moment to define “belief”, but a criterion is influence on action. If I say “suppose there were a tiger outside your front door”, you will remain calm; but if I say, with such a manner as to command belief, “there is a tiger outside your front door”, you will stay at home, even if it involves missing your train to the office. This illustrates what I mean when I say that imagination, in its developed form, involves absence of belief. But this is not true of its primitive forms. And even a civilised adult, passing through a churchyard on a dark night, may feel fear if his imagination turns in the direction of ghosts. When imagination passes into belief, it does not, as a rule, become a belief about the past. Generally we place the imagined object in the present, but not where it would be perceptible to our senses. If we place it in the past, it is because the past has some great emotional significance for us. If a person we love has been in great danger, and we do not know whether he has come through safely, imagination of his death may lead us to believe that he has been killed. And often imagination leads us to believe that something is going to happen. What is common to all such cases is the emotional interest: this first causes us to imagine an event, and then leads us to think that it has happened, is happening, or will happen, according to the circumstances. Hope and fear have this effect equally; wish-fulfilment and dread-fulfilment are equally sources of dreams and day-dreams. A great many beliefs have a source of this kind. But, in spite of psycho-analysis, there are a great many that have a more rational foundation. I believe that Columbus first crossed the ocean in 1492, though 1491 or 1493 would have suited me just as well. I cannot discover that there is any emotional element in this belief, or in the belief that Semipalatinsk is in Central Asia. The view that all our beliefs are irrational is perhaps somewhat overdone nowadays, though it is far more nearly true than the views that it has displaced.