We saw that practical belief is not altogether independent of experiential belief. Neither is the latter independent of the former. When two theories agree equally well with experiential facts, we accept the one that is simpler. Not because we know that it is nature’s obligation to proceed in the simplest manner possible, and that therefore the simpler theory is more likely to be correct; but because our practical needs compel us to accept a simpler theory whenever we can. We believe the Copernican theory of the solar system and reject the Ptolemaic system. Not because one is more correct than the other; but because the Copernican system combines the same objective fitness with an immeasurably greater simplicity. The simple we desire; the simple, therefore, we believe. A simple connection of a variety of things is pleasant, beautiful. It is easy to survey it. It takes but a small amount of mental energy to imagine it. Whenever our experiences leave us a choice, we choose what is simpler. In other cases, too, practical belief comes to the aid of experiential belief. In the border regions of knowledge and within the blank spaces found within the field of knowledge, belief must take the place of knowledge. QUESTIONS 170. What is the difference between objectively correct thought and belief? 171. What is the wider and what the narrower meaning of “belief”? 172. How do the ideas of reality and of unreality originate in the child? 173. Why are we more inclined to apply the concept of reality than that of unreality? 174. What is the double influence of experience on the child’s belief? 175. Should authoritative belief be eradicated? Give reasons for your answer. 176. Should practical belief be eradicated? Give reasons for your answer. 177. What is a superstition? 178. Why do we believe the Copernican theory and reject the Ptolemaic theory? B. _Affection and Conduct_ § 19. COMPLICATIONS OF FEELING 1. _Feeling Dependent on Form and Content_ Perception and ideation rarely, if ever, occur in the isolation in which they were shown above in order to make clear their structure: they are accompanied by, interwoven with, feelings. A summer landscape not only looks different from the same landscape when covered with snow, but also arouses different feelings. I may look forward to the same event--an ocean voyage or an automobile tour--as a danger or as a pleasure; I may regard an assertion as a truth or as doubtful. The ideas of which I am conscious surely differ much in the alternative cases. But still greater is the difference of feeling to which we refer by such terms as _fear_, _low spirits_, _disquietude_, _comfort_, _joy_. The exact make-up of these complexes of feeling is difficult to describe, but we may try to point out the conditions on which they depend. We shall first consider form and content.