There are many other motives to activity than acquisition, but there are many evidences of its intense operation even in modern society. Many men go on working long after they have money enough to enable them to live in comfort, merely for the further satisfaction of this impulse. "While in the course of satisfaction of most other desires, the point of satiety is soon reached, the demands of this one grow greater without limit, so that it knows no satiety."[1] [Footnote 1: McDougall: _loc. cit._, p. 323.] The power of this tendency to personal acquisition and possession seems an obstacle to all thoroughly communistic forms of political and social organization. The conception of a state where nobody owns anything, but where all is owned in common--an idea which has been repeated in many modern forms of socialism and communism, fails to note this powerful human difficulty. Many socialist writers, it must be noted, however, point out that they wish social ownership of the means of production rather than of every item of personal property, such as books, clothing, and the like. INDIVIDUALITY IN OPINION AND BELIEF. Men frequently display with regard to their opinions and beliefs the same passionate attachment that they exhibit with regard to their physical possessions. Like the latter, these come to be regarded as an extension of the individual's personality, and the same tenacious defense may be made of them as of a house, land, or money. Individual opinions and beliefs are not themselves possessions, from a social point of view, so much as is the right to express them. A man's private opinion may influence his own conduct; his conduct itself may be an expression of opinion. But unless an opinion is communicated, it cannot influence any one else's conduct, and society has never been much concerned about opinions that an individual harbored strictly in his own bosom. Silence, socially, is as good as assent. The insistence on the right to one's own opinions becomes, therefore, an insistence on the right or the freedom to express them.[2] This right is cherished in varying degrees by different individuals in different ages. It becomes pronounced in persons in whom there is marked development of individuality, and, in general, where, as in Anglo-Saxon countries, a social and political tradition of liberty and individuality has become very powerful. [Footnote 2: Beliefs and opinions may come to be regarded as important personal possessions in themselves, as in the case of rival claimants to some theory or idea, as in the case of Leibnitz's and Newton's dispute over the calculus.]