Ernest Mathijs and Bert Mosselmans
First, similarities between natural sciences, social sciences and art and aesthetics will be discussed from an external-scientific, sociological point of view, using the theories of Kuhn and Barnes. Second, differences in methodology and points of departure, which seem to undermine the bridges between the disciplines mentioned, will be examined. These differences will be revealed by reviewing some unifying proposals from the past : logical positivism, Popper's falsificationism, modernist aesthetic categorisation. The third part reviews the proposals of Feyerabend, McCloskey and Beuys, in order to overcome the difficulties stated in the second part.
The object of our contribution is to discuss the possibilities for interdisciplinarity between natural sciences, social sciences and art and aesthetics. Therefore, we will first direct our attention towards the similarities and differences between the disciplines mentioned.
The similarities between the disciplines will be discussed using the theoretical frameworks of Thomas Kuhn and Barry Barnes.
According to Kuhn, the common practice in the natural sciences is puzzle-solving, or the articulation of a specific guiding paradigm. This paradigm is a way of looking to the world, a habit of mind, shared by a scientific community, thus tying it together. Shared habits of mind are the only essential constitutions tying together a scientific community : without shared habits of mind effective scientific communication becomes impossible. Science evolves gradually by the process of puzzle-solving, until some unexpected outcomes occur. Once the existence of an anomaly is accepted, normal science turns into crisis. When the crisis has been overcome by a new paradigm, a reconstruction of the field from new fundamentals takes place. Revolutions can thus be viewed as changes of world view. 
Kuhn states that his theory can only be applied to "mature" science, a science which possesses a generally accepted paradigm. Since in the social sciences more than one paradigm exists, application of Kuhn's theory to these fields of inquiry seems problematic.
"Normal social science" cannot be identified within the global process of scientific development, only within the context of one of the competing "paradigms". "Revolutions" do occur here, but they do not necessarily lead to the abandonment of an older "paradigm".
As in social science, in art history more than one "paradigm" can be identified at one moment. As in the social sciences, artistic development can only be identified within the context of one of the existing "paradigms". This does not necessarily mean that these "paradigms" are competing. Moreover, a controversy between supporters of a new and an old "paradigm" often only means the acceptance of the new tradition rather than the end of the old; on the whole, older paradigms are kept alive. 
Kuhn's theory does make sense in the three branches of human knowledge investigated, but in a differing way. The natural sciences work with one predominant paradigm, whereas in social science and art more than one "paradigm" can exist at the same time. A "revolution" has a different effect : in the natural sciences, it leads to the abandonment of the older paradigm; in the social sciences, this abandonment can occur but not always does, and in art this abandonment does not occur.
According to the sociologist Barnes, science is a constructivist human activity. Science tries to represent reality by constructing metaphors, but in conjunction with certain socially and historically established conventions. According to Barnes, ideas should be viewed as instrumental tools with which social groups try to achieve their purposes in particular situations. A scientist creates a metaphor concerning the surrounding world, starting from initial knowledge, and guided by overt and covert interests. The overt interests are concerned with prediction, manipulation and control; the covert interests deal with rationalisation and persuasion, but are not identical to ideology. Since individuals are embedded in specific social institutions, those should be kept in mind when trying to understand what scientists meant by what they actually said. 
Scientific development takes place within social institutions, for the greater part universities. A natural scientist studies the standard textbooks used in his discipline, thus learning the predominant paradigm. Although there are different textbooks available, the contents will be nearly the same.
This does not apply to the social sciences. The books used by the tutor will depend on the paradigm he subscribes. Recruitment will take place by teaching the new members the appropriate methods and examples. "General" textbooks do however exist, as in economics, but they subscribe the "mainstream" paradigm. The existence of alternative paradigms is shown by the existence of alternative textbooks.
For art, the institutions are generally described as the art world : a network of people whose co-operative activity, organised via their joint knowledge of conventional means of doing things, produces the kind of art works that the art world is noted for. As far as recruitment is concerned : an artist can only present himself as an artist if his claim is institutionalised. This means that the artist places himself within an already existing artistic context (by exposing or performing his work). This context is controlled not by him, but by `significant others' (the colleague, the maecenas, the academy, the salon,...). Thus the artist is recruited in a tradition, similar to those of scientists. 
Natural sciences, social sciences and art and aesthetics have a common point of departure: the existing institutions that guide further development of social metaphors. These institutions are socially mediated human activities. They are guided by two kinds of interests, and they start by the metaphors used in the past.
The differences between the three fields thus have to be found in the different nature of these common points.
The differences are revealed by discussing some proposals from the past.
A first proposal was logical positivism. The ultimate goal was the reduction of all scientific terms to elementary unambiguous terms, in natural as well as in social science. Concepts concerning social behaviour should be reduced to concepts concerning individual behaviour, which should be reduced to physiological concepts, and so forth. 
Reducibility turned out to be an illusion : when subjectivism is taken as foundation, in terms of Carnap's elementary sense-data, intersubjectivism becomes problematic; when objectivism is taken as foundation, in terms of Carnap's "thing-language", the objectivity itself can be questioned since experiences are in essence subjectivistic. On the whole, by reducing scientific terms to elementary sense-data logical positivism tried to reduce the subject investigating to the object investigated - the subjective experiences of the investigator are objectified. The case for social sciences is even worse : after reducing the subject investigating to the subjects investigated, one has to reduce the subjects investigated to objects investigated. The first reduction identifies the researcher's thoughts with the subjective reality of the subject, the second reduction objectifies this subjective reality. Logical positivism failed to bridge the epistemological gap between subject and object.
The failure of logical positivism led Popper to formulate his well-known falsification criterion. In Popper's view, all science starts from the subject investigating. This subject tries to put a self-consistent meaning into a world that appears to it. The epistemological problem is not solved, but avoided : we can never be sure to have established a subject-object-correspondence, since we are in need of a background knowledge, in order to see whether a specific statement is falsified or not. When the telescope is defect, astronomical observations are worthless.  According to Kuhn, this background is embedded in a paradigm, in a way of looking to the world. This paradigm is embedded in specific institutions of a scientific community. For our purposes, the legacy of Popper is the following : we cannot reduce the subject investigating to the object investigated.
The case of social science is even more difficult, since more than one paradigm exists, and thus more than one possible background knowledge. The subjective position of the investigator thus is even more important than in the case of the natural sciences, but should be neutralised within the scientific discourse. Intersubjectivistic discussion within specific institutions should function as objectifier of subjectivistic statements.
Modernism, a well-known proposal for art and aesthetics, also puts the emphasis on the subject investigating by attempting to secure the autonomy of art. This was constituted by a strategy of exclusion, by a fear of contamination by mass culture. It led to a tendency towards specialisation, and individualism. The autonomy of the work of art, which was thus achieved, would be defended by disconnecting art from the real world. The emphasis on the subject investigating was amplified by the concept of the artist-genius, which is pure individualistic in its methodology. So, in modernist art, not the object that is investigated is of any significance, but the subject investigating (the author). 
In recent decades modernism came under criticism. It is Joseph Beuys who tried to make art play an emancipative role, by trying to smash the boundaries between art and life. His contribution will be described later on.
Let us now try to sum up some of the differences between natural sciences, social sciences and art and aesthetics. We will direct our attention towards the subjects investigating and objects investigated, and towards the role of interests and the past.
The unity of natural sciences, social sciences and art and aesthetics lies in the common point of departure : the subject investigating, which is embedded in institutions tied together by paradigms. The mediation towards the objects of investigation, however, is different.
The natural scientist is concerned with objective reality. In accordance with the guiding paradigm and the specific institutions (like universities or scientific journals), the subject investigating builds a mirror of the object investigated. Thus, the subjective experiences of the investigators become objectified, in a process of normal science.
The social scientist is concerned with the objective appearances of subjective reality. The social scientist also builds a mirror, but here the subjective experiences of the investigator become objectified through mediation of an intersubjectivistic discussion within specific institutions that subscribe to the same specific paradigm. Here, objectivity is a relative concept, since it is reached only in relation to a specific paradigm.
In art and aesthetics, the subject investigating pursues neither objectivity nor intersubjectivity. The author's individuality is the sole significant item in his method. Nevertheless, art world institutions and so called objective criticism play a regulating role in the channelling of this subjective method, since they provide the paradigm upon which the author bases himself, as well as the culture in which such subjective research is possible.
According to Barnes, overt and covert interests are involved in the process of creating scientific metaphors. The overt interests are expressed in the official rhetoric of prediction, manipulation and control. The covert interests have to do with the desire for rationalisation and persuasion. This view can be applied both to natural and social sciences, as well as to art and aesthetics.
When covert interests are directed towards non-scientific institutions, differences occur. Here, natural sciences are concerned with showing that the investigations are relevant. Problems concerning ecological or ethical aspects occur, but these have nothing to do with the governing paradigm as such. In social sciences, covert interests can only be justified when crucial metaphysical presuppositions of the paradigm are shared with the authorities.  In art and aesthetics a clear view is distorted by the variety of possibilities. The potential active role of enterprises and the public tends to secure the autonomy of art work, but their guiding principles are even more hidden.
Kuhn noted that the natural sciences are not concerned with their history. Textbooks are organised thematically, not historically. Major changes do only occur during important scientific revolutions, like the general acceptance of Einstein's theory of relativity.
Textbooks fulfil the same function in social sciences. The field of economics, for instance, is presented as being a unified, a-historical body of undisputed, eternal knowledge. The only difference seems to be the existence of textbooks that refer to non-mainstream traditions, which account for the fact that the field is not so unified as some people would like to have it.
The evolution in art and aesthetics shows differences. Because of the necessity of historical arguments in aesthetics, most textbooks are organised historically. Moreover, constructing thematically organised textbooks proves to be very difficult, because of the wide variety of themes, which are the result of the rigid subjectivity of the investigator. Since the subjectivity of the artist is the important thing, a-historical textbooks based upon objective topics seem to miss the point.
All human intellectual activity starts from the subject investigating, which is embedded in specific institutions tied together by a guiding "paradigm". These institutions function as objectifying instances through intersubjectivistic mediation. Individuals direct their interests, overt and covert, towards these institutions by establishing metaphors concerning objects or subjects investigated. They identify themselves against the past in order to do this. Although important differences concerning these mechanisms between natural and social sciences, and art and aesthetics can be identified, this basic scheme applies to all these activities. Therefore, this scheme will form the base of an outlook on a unified human activity. In order to do this, we will discuss the proposals of Paul Feyerabend, Donald McCloskey and Joseph Beuys.
According to Feyerabend, important achievements in natural science can only occur by refusing to narrow the methodological rules : Feyerabend's message is "anything goes". Contemporary science wants to wipe out everything that is regarded as non-scientific. Researchers who do not subscribe the generally accepted methods, are not appointed; scientific articles which do not follow the "obvious" patterns are not published. Disciplines which are regarded as non-scientific, like astrology, are excluded; this gives rise to a loss of a potential for new developments. 
Feyerabend's proposal tends towards the situation in the social sciences : lots of different paradigms exist, each having its own institutions and followers. Furthermore, science should be brought on a more general plane, not only including professional scientists. His mediation principle is democratic voting, functioning as objectifier of the different possible solutions. But, are the preconditions for this mediation mechanism fulfilled ? Can people decide between different theories, embedded in differing incommensurable paradigms ? We are in a need for a mediation principle between different paradigms in order to overcome the problem of incommensurability. Since this problem already occurs in social science, we will now direct our attention towards the proposals of the economist Donald McCloskey.
According to McCloskey, economics, and social science in general, is ruled by modernism. This modernism forms the official rhetoric of economists - it can generally be described as the official scientific rules, held to be justified for other scientific branches too. But that's not all - there is an unofficial rhetoric too. This unofficial part contains everything that is unspoken and unreflected. 
The incommensurability problem derives from the usage of differing paradigms, having their own institutions and adherents. The precondition of this incommensurability precisely is the existence of unspoken and unreflected starting points; it is the unofficial rhetoric. The real problem concerning incommensurability is not that defenders of differing "paradigms" do not understand each other, the real problem is that they do not understand themselves.
When a scientific paper is published, the real important thing has disappeared : everything is presented as if it follows a logical chain from beginning to end, thus hiding the problem-situation, the different lines of thought that have not been pursued, the reasons why this has not been done, the errors made during the process and so on. Writing self-critically could uncover good reasoning and facilitate understanding, so literary criticism provides a model of scientific self-consciousness.
Where Feyerabend bridges the gap between natural and social sciences, McCloskey does it the other way around. Science (or human intellectual activity in general) is first of all a problem of intersubjectivity. In social science, ruled by different paradigms, or in a broaden natural science à la Feyerabend, the preconditions for intersubjectivistic discussion have to be fulfilled. The scientists should reflect about and reveal the actual starting point, and they should talk about what they are doing and not about what they have done. A reflexive methodology is needed; we should know why the science we are getting is the one we are getting, and we should study how the actual process of science takes place and has taken place during the past. 
Science tried to account for the reduction of subject investigating to subject or object investigated, without considering the precondition for intersubjectivistic communication. This precondition is in fact the dialectical antipode of the former : the reduction of subject or object investigated to subject investigating, since we have to understand and reflect on the ways we approach object or subject investigated. However, we slip into a dangerous situation : when reduction from subject investigating to the object of investigation can only be done by reduction from object of investigation to subject investigating, the object is fading away. In order to avoid the postmodern empty box, a unifying synthesis has to be found - in the "plastic theory" of Joseph Beuys.
Joseph Beuys has made an attempt to bridge the gap between the subject investigating and the object investigated. His `plastic theory' simply states that everyone is an artist, or, more exactly, that everyone can be an artist. There are, however, two preconditions: `the border-dissolving of art and life' and `the idea of creativity'.
These preconditions have two important characteristics: the turning of the role of the perceiver, and the expansion of human consciousness. According to Beuys the perceiver can become equal to the creator by stressing human qualities such as intuition, inspiration, feeling, freedom... It is especially in art that these qualities can be activated.
To activate them, Beuys pled for what he called an expansion of human consciousness, or Bewußtseinserweiterung. This is a process of rethinking things, of using other methods and methodologies, of finding new coherences. In this process the notion of artistry will be generalised to all aspects of human activity. As a consequence, every human act is artistic, and therefore every human is an artist. 
In Kuhn's words, the natural sciences are governed by one ruling paradigm, around which specific institutions are created. Feyerabend wants to break the current paradigm, and make place for more. His proposal can only be effective when the precondition of understanding oneself and the other is fulfilled.
According to McCloskey, we should reflect on the unreflected, and talk about the unspoken, to facilitate understanding. The official rhetoric of the institutionalised paradigm is not sufficient. "Feeling" and "experience" and the unofficial rhetoric play an equally important role. Understanding, rhetoric and interests should become unified. However, we should avoid the postmodern empty box.
The problem can be stated as follows: a discussion within an institution is not fruitful, since the role of creativity diminishes. Discussion without any form of institution is impossible, since everyone stays on his postmodern island. The solution seems to be found in Beuys' `plastic theory'. We should dissolve the boundaries between institution and discussion. The discussion itself should be the institution.
In order to promote creativity, the boundaries between art and life, science and life, and art and science have to be dissolved. In order to avoid repression by theories, institutions or paradigms he created himself, a scientist should do what he is, be what he does, think about what he is and is doing and discuss what he thinks he is doing. A scientist should think what he wants, and want what he thinks, in order to feel what he is thinking.
 Kuhn, T., The Structure of Scientific Revolutions, Chicago University Press, Chicago, 1973, Margolis, H., Paradigms and Barriers. How Habits of Mind Govern Scientific Beliefs, The University of Chicago Press, Chicago and London, 1993.
 Best, R., 1977. Sketch for a Sociology of Art, British Journal of Aesthetics, 17, 1977, Kuhn, T. S., 1977. The Essential Tension. Selected Studies in Scientific Tradition and Change., University of Chicago Press, Chicago, 1977, Van Dooren, W. & Hoff T., (eds.) Aktueel filosoferen, Eburon, Delft, 1993.
 Barnes, B. Scientific Knowledge and Sociological Theory, RKP, London, 1974, Interests and the Growth of Knowledge, RKP, London, Boston and Henley, 1977, On the Extensions of Concepts and the Growth of Knowledge, Sociological Review, 30, 1982, Social Life as Bootstrapped Induction, Sociology, 17, 1983, Restivo, S., The Social Relations of Physics, Mysticism, and Mathematics. Studies in Social Structure, Interests, and Ideas, D. Reidel Publishing Company, Dordrecht, Boston, Lancaster, 1983.
 Wolfe, T., The Painted Word/ From Bauhaus to our House, Jonathan Cape, Londen, 1981, Hauser, A., The Sociology of Art, Routledge & Kegan Paul, Londen, 1982, Becker, H., Art Worlds, University of California Press, Berkeley, 1982, Elias, W., Tekens aan de wand; hedendaagse kunsttheoriëen, Hadewijch, Antwerpen, 1991.
 Hanfling, O., Logical Positivism, Basil Blackwell, Oxford, 1981, Mokrzycki, E., Philosophy of Science and Sociology, RKP, London, 48-67, 1983, Gordon, S., 1991, The History and Philosophy of Social Science, Routledge, London, 593-596, 1991.
 Popper, K., The Logic of Scientific Discovery, Harper & Row, New York, 1965, Conjectures and Refutations. The Growth of Scientific Knowledge, RKP, London, 1969, Auf der Suche nach einer besseren Welt, Piper, München, 1984.
 Stolnitz, J., Aesthetics and Philosophy of Art Criticism, Riverside Press, Boston, 1960, Benjamin, W., Gesammelte Schriften, Suhrkamp Verlag, Frankfurt, 1974, Burgin, V.,The End of Art Theory; Criticism and Postmodernity, MacMillan, Basingstoke, 1986, Huyssen, A,. After the Great Divide; Modernism, Mass Culture, Postmodernism, Indiana University Press, Bloomington, 1986, Harrison, C. & Wood, P. (Eds.), Art in Theory; 1900-1990; an Anthology of Changing Ideas, Blackwell, Oxford, 1992.
 Glass, J., Johnson, W., Metaphysics, MSRP and Economics, The British Journal for the Philosophy of Science, 39, 1988.
 Feyerabend, P., Against Method, NLB, London, 1975, Erkenntnis für freie Menschen, Suhrkamp, Frankfurt a.M., 1979.
 McCloskey, D., The Rhetoric of Economics, Journal of Economic Issues, 21, 1983, The Rhetoric of Economics, Harvester, Brighton, Sussex, 1986.
 Jenkins, K., Re-thinking History, Routledge, London and New York, 1991.
 Beuys, J., Not Just a Few are Called, but Everyone, Studio International, 184, 1972, Beuys, J., I am Searching for Field Character, Art into Society-Society into Art-catalogue, Institute of Contemporary Arts, Londen, 1974, Van Mulders, W., Joseph Beuys : de metamorfose van het litteken, Streven, 1979, Oman, H., Die Kunst auf den Weg zum Leben: Joseph Beuys, Quadriga, Berlin, 1988, Mathijs, E., Kunstkritiek en hedendaagse kunst (J. Beuys): communicatieve functies, Unpublished Dissertation, VUB, Brussel, 1992, Mathijs, E., Joseph Beuys: de ontgrenzing van kunst en leven, Nieuw Tijdschrift van de Vrije Universiteit Brussel, 2, 1993.