Social interactions are the acts, actions, or practices of two or more people mutually oriented towards each other's selves, that is, any behavior that tries to affect or take account of each other's subjective experiences or intentions. This means that the parties to the social interaction must be aware of each other--have each other's self in mind. This does not mean being in sight of or directly behaving towards each other. Friends writing letters are socially interacting, as are enemy generals preparing opposing war plans. Social interaction is not defined by type of physical relation or behavior, or by physical distance. It is a matter of a mutual subjective orientation towards each other. Thus even when no physical behavior is involved, as with two rivals deliberately ignoring each other's professional work, there is social interaction.