3. "Predominant Passions. Thirdly, probabilities which cross men's appetites and prevailing passions run the same fate. Let ever so much probability hang on one side of a covetous man's reasoning, and money on the other, it is easy to foresee which will outweigh. Earthly minds, like mud walls, resist the strongest batteries. [Sidenote: of dependence upon authority of others] 4. "Authority. The fourth and last wrong measure of probability I shall take notice of, and which keeps in ignorance or error more people than all the others together, is the giving up our assent to the common received opinions, either of our friends or party, neighborhood or country." [Sidenote: Causes of bad mental habits are social as well as inborn] Both Bacon and Locke make it evident that over and above the sources of misbelief that reside in the natural tendencies of the individual (like those toward hasty and too far-reaching conclusions), social conditions tend to instigate and confirm wrong habits of thinking by authority, by conscious instruction, and by the even more insidious half-conscious influences of language, imitation, sympathy, and suggestion. Education has accordingly not only to safeguard an individual against the besetting erroneous tendencies of his own mind--its rashness, presumption, and preference of what chimes with self-interest to objective evidence--but also to undermine and destroy the accumulated and self-perpetuating prejudices of long ages. When social life in general has become more reasonable, more imbued with rational conviction, and less moved by stiff authority and blind passion, educational agencies may be more positive and constructive than at present, for they will work in harmony with the educative influence exercised willy-nilly by other social surroundings upon an individual's habits of thought and belief. At present, the work of teaching must not only transform natural tendencies into trained habits of thought, but must also fortify the mind against irrational tendencies current in the social environment, and help displace erroneous habits already produced. § 4. _Regulation Transforms Inference into Proof_ [Sidenote: A leap is involved in all thinking]