Coordination issues between actors and the conditions for fulfilling their respective agreements have led some authors to postulate that actors rely on conventions and higher common principles in order to set up equivalences between things, people and events. There are thus common frameworks that make discussion possible, whether this is for a specific point or a regular event. Higher common principles therefore govern systems of reciprocal expectation. The members of these "common worlds" expect others to act according to the principles of the common world in which they are located. These worlds constitute systems of equivalence that are justified and inside which the greatness or smallness of a being or an action can be assessed. They define markers and help to settle disagreements. These equivalence systems are characterised by: a higher common principle, a definition of the greatness or smallness of a status, a foundation based on dignity, qualified subjects and objects, a type of cost or risk, a ratio of greatness and a type of relation, a figure of harmony, a type of test determining the state of greatness and a way of expressing judgement and proof.
The number of these equivalence systems or "common worlds" is not unlimited. Six have been identified:
The industrial city
The industrial city is based on the higher common principle of efficiency and performance. It refers to the organisation and implementation of rational methods as well as to the mobilisation of science and modern technology. In this world, greatness is linked to performance and functionality; it is determined by tests, the results of which should ideally serve as a measurement. Greatness is judged in terms of efficiency and compliance with a standard. Dignity is tied to work. Smallness is expressed in terms of inefficiency and non-functionality, makeshift efforts, empirics and a lack of rationality. The subjects are the professionals and the objects the means. The natural relationship stems from the way items of differing greatnesses function and from the relations of control between them. Harmony comes from the systemic nature of the whole set of functional interactions, from the perfect operation of a machine. Cost is linked to the agreed investment and to progress-related risks.
The trading city
This is based on the higher common principle of competition and rivalry. It refers to the fluidity of arrangements and transactions. In this world, greatness is linked to the exchange value, to desire and to gain; it is determined by how successful business is and how many contracts are signed. This is what constitutes the test of greatness. The results are measured in terms of gain and economic benefits (income statement). Greatness is judged in monetary terms, by the price. Dignity is based on interest. Smallness comes from losing. The subjects are competitors and customers; the objects are wealth or resources. The natural relationship is that of business and profit-sharing while the ratio of greatness is based on possession. The ideal figure of harmony is that of the market. Investment and risk are linked to opportunism.
The civic city
This is based on the higher, common principle of collective pre-eminence over the individual. Greatness is linked to representativity and legality; it is determined by the test of demonstrating for a worthy cause, complying with rules and acting according to the outcome of a vote. Results are measured in terms of legal texts and legitimate rules. Dignity comes from the basic respect of freedom, from the defence of citizenship and from solidarity. Smallness is expressed in terms of division and isolation. The subjects arc collectives and the objects are legal forms. The natural relationship is that of gathering together for collective action while the ratio of greatness is tied to membership and delegation. The ideal figure of harmony is that of the republic. Investment and risk are linked to individual abnegation for the benefit of solidarity.
The opinion city
This is based on the higher common principle of the pre-eminence of other people's opinion. It refers to reputation. In this world, greatness is linked to the fact of being known and recognised; it is determined by the test of presenting an event and performing well, in the artistic sense of the term. The result is measured in terms of success and recognition. Greatness is judged by the opinion of the majority. Dignity is based on the desire to be considered. Smallness comes from commonness and the fact of being unknown. The subjects are stars and the objects are messages (name, brand, label, indexes). The natural relationship is that of persuasion, while the ratio of greatness is based on identification.
The ideal figure of harmony is that of a large audience. Investment and risk are linked to the renunciation of discretion, private life and secrecy.
The inspired city
this is based on the higher common principle of originality and commensurability. It refers to inspiration. In this world, greatness is linked to spontaneity and difference; it is determined by the test of personal and internal adventure. Objects and people are valued for their originality, regardless of whether they conform, have economic value or are popular. The result is measured in terms of intuitive certainty. Greatness is measured in terms of flashes of genius. Dignity is based on passion and creation. Smallness is marked by routine, conformity and submission. The subjects are artists, messiahs or children; the objects are bodies or minds. The natural relationship is that of imagination, dream and creation, while the ratio of greatness is based on singularity. The ideal figure of harmony is that of the imaginary. Investment and risk are linked to creation.
The domestic city
This is based on the higher common principle of personal relationship and tradition. It refers to respect for a hierarchy of peers. In this world, greatness is linked to the position held on the ladder and to an attitude of benevolence; it is determined by the performance of and respect for ceremonies. The result is measured in terms of example. Efficiency comes from following the example of one's peers. Greatness is judged in terms of appreciation. Dignity is based on common sense, respect for this and for traditions and on ease. Smallness comes from vulgarity and a lack of consideration for others. The subjects are ascendant or descendant family members while the objects are presents, gifts and precedence. The natural relationship is that of education and reproduction, while the ratio of greatness is based on subordination and the expression of honour. The ideal figure of harmony is that of the family or milieu. Investment is duty.