It has been customery to use the concept of self-determination in the sense of the right of a people to decide about its own destiny instead of being ruled by another nation. However, people who belong to a ruling nation are themselves ruled by a power elite. Thus the concept may be generalized and taken in the sense of self-government, i.e. the right of all human individuals who belong to a community to take care of their problems without control or interference of an alien social force, such as the State, the political party, the church, the market, etc. Then if we ask what is there to justify these rights we might wish to say that self-determination is the distinguishing characteristic of human behaviour and that the whole process of the making of history is essentially self-determination, different from the blind objective determination that takes place in natural processes. Such a basic idea of the philosophy of history would involve a most general methodological principle that regulates our inquiry of human behaviour and allows us to make an important distinction between specifically human activities and reified ones, i.e. those in which man is reduced to a mere object, to a measurable, fully predictable physical thing. Such a principle might play very great role in building up a critical social theory: it allows us to form an overall critical view of a whole historical situation and to get a sense of direction.