Interdisciplinarity as a personal characteristic is basically a mental outlook which combines curiosity with openmindedness and a spirit of adventure and discovery. It includes the intuition that relationships exist between all things which escape current observation and that there are analogies of behaviour or structure which are perhaps isomorphic. It is not learnt, it is practised as the fruit of continual training and systematically working towards more flexible mental patterns.
Six levels of interdisciplinarity may be distinguished in order of stage of maturity: 1. Indiscriminate interdisciplinarity, including all kinds of encyclopaedic endeavours, usually conceived as a form of vocational training for those having to handle a variety of problems; 2. [Pseudo-interdisciplinarity] in which analytical tools such as mathematical models or computer simulation are applied to different subject matter as a uniting core for cross-disciplinary research and training, but with subordination of the different contents; 3. Auxiliary interdisciplinarity whereby an auxiliary disciplinarity arises from the application of the methods of one discipline to the subject matter of another discipline; 4. [Compositive interdisciplinarity] whereby a composite discipline arises from the need to focus a variety of disciplines on a particular issue area ([eg] peace research, urban planning) and is usually noteworthy for its technological instrumentality in pursuing a hierarchical sequence of clearcut goals which change person-environment systems or even innovate such systems; 5. Supplementary interdisciplinarity, in which disciplines in the same material field develop a partial overlapping in a supplementary relationship between the respective subject matters. (Such closer integration of two or more disciplinary subject matters is looked for and tentatively established in order to reconstruct life or social processes more fully); 6. Unifying interdisciplinarity resulting from an increased consistency in the subject matter of two disciplines, paralleled by an approximation of the respective theoretical integration levels and methods.
Three types of interdisciplinarity may be distinguished: 1. Linear interdisciplinarity, when a crude phenomenon belonging to one discipline is legalized by a law belonging to a second discipline, in the sense that the law is borrowed and adapted by the first discipline for the benefit of the phenomenon. (This has been commonly called by terms such as multidisciplinarity, pluridisciplinarity, or crossdisciplinarity). 2. [Structural interdisciplinarity], in which interactions between two or more disciplines lead to the creation of a body of new laws forming the basic structure of an original discipline that cannot be reduced to the formal combination of its generators, and may itself absorb them through a syncretic tendency ([eg] electromagnetism). 3. Restrictive interdisciplinarity, in which the field of application of each discipline brought into play by the concrete objective is restricted, such that each discipline imposes technical, economic or other constraints on the application of the others, but there is no other interaction between the disciplines.
For example, crossdisciplinarity is an approach in which the organizing principle and goals of one discipline are imposed upon other disciplines. Crossdisciplinarity thus implies a brute-force approach to reinterpret disciplinary concepts and goals (axiomatics) in the light of one specific (disciplinary) goal. One of the most conspicuous attempts of crossdisciplinary polarization is the reformulation of management, planning, organization, and the explicit planning of change, in terms of the empirical and reductionist concepts of the applied behavioural sciences.
Transdisciplinarity coordinates all disciplines and interdisciplines through a common system of goals. The essential characteristic of a transdisciplinary approach is the cooperation of activities at all levels of the education/innovation system. In the successive steps of cooperation and coordination between disciplines, transdisciplinarity defines an organizational principle for a hierarchical system of multiple levels, having multiple goals, and in which there is coordination of the whole system toward a common goal. With transdisciplinarity, the whole education/innovation system is thus coordinated as a multilevel, multi-goal system, embracing a multitude of coordinated interdisciplinary two-level systems.