The average brain is naturally lazy and tends to take the line of least resistance. The mental world of the ordinary man consists of beliefs which he has accepted without questioning and to which he is firmly attached; he is instinctively hostile to anything which [9] would upset the established order of this familiar world. A new idea, inconsistent with some of the beliefs which he holds, means the necessity of rearranging his mind; and this process is laborious, requiring a painful expenditure of brain-energy. To him and his fellows, who form the vast majority, new ideas, and opinions which cast doubt on established beliefs and institutions, seem evil because they are disagreeable. The repugnance due to mere mental laziness is increased by a positive feeling of fear. The conservative instinct hardens into the conservative doctrine that the foundations of society are endangered by any alterations in the structure. It is only recently that men have been abandoning the belief that the welfare of a state depends on rigid stability and on the preservation of its traditions and institutions unchanged. Wherever that belief prevails, novel opinions are felt to be dangerous as well as annoying, and any one who asks inconvenient questions about the why and the wherefore of accepted principles is considered a pestilent person. The conservative instinct, and the conservative doctrine which is its consequence, are strengthened by superstition. If the social structure, including the whole body of customs and opinions, is associated intimately [10] with religious belief and is supposed to be under divine patronage, criticism of the social order savours of impiety, while criticism of the religious belief is a direct challenge to the wrath of supernatural powers. The psychological motives which produce a conservative spirit hostile to new ideas are reinforced by the active opposition of certain powerful sections of the community, such as a class, a caste, or a priesthood, whose interests are bound up with the maintenance of the established order and the ideas on which it rests. Let us suppose, for instance, that a people believes that solar eclipses are signs employed by their Deity for the special purpose of communicating useful information to them, and that a clever man discovers the true cause of eclipses. His compatriots in the first place dislike his discovery because they find it very difficult to reconcile with their other ideas; in the second place, it disturbs them, because it upsets an arrangement which they consider highly advantageous to their community; finally, it frightens them, as an offence to their Divinity. The priests, one of whose functions is to interpret the divine signs, are alarmed and enraged at a doctrine which menaces their power. In prehistoric days, these motives, operating