Of the two main groups of tendencies to which we have above referred--which we may briefly call the love and hate groups--the former opens up a number of problems in this connection which would seem to be in some significant respects deeper, more important and more complex than those raised by the latter. The hate tendencies are, indeed, as regards the cause and nature of their origin and development, in the main not so very difficult to understand. Psychologists are pretty well agreed as to the circumstances which give rise to anger and fear--the emotions which chiefly underlie the attitude of hate. Anger arises when the activities, tendencies or wishes of the individual are interfered with or when the individual is unwillingly forced to undergo some disagreeable or undesirable experience, and it is directed to the object from which such interference or such infliction of undesired experience is forthcoming. Fear arises when harm is threatened to the individual or to that which he possesses or holds dear, and is directed to the threatening object[216]. Now, as we have seen, the normal conditions of family life necessarily give rise to some extent to the situations which arouse these emotions. Through the mere exercise of ordinary parental authority and care, and more especially through the process of elementary moral training and education, the parent invariably interferes in some ways with the primitive desires and tendencies of the child, and threatens the child with punishment in the event of his transgressing the parental prohibitions; the conditions are therefore present for the arousal in the child's mind of anger and fear towards the parent, should the child be at all susceptible to these emotions. [Sidenote: Jealousy as a necessary consequence of marriage]