al. (2008) conclude that one can understand why transdisciplinary research is shaped by various lines of thinking and has a variety of definitions. We thus present here the definition derived by the same authors, which is based on a synthesis of what can be found in the literature:
There is a need for transdisciplinary research when knowledge about a societally relevant problem field is uncertain, when the concrete nature of problems is disputed, and when there is a great deal at stake for those concerned by problems and involved in dealing with them. Transdisciplinary research deals with problem fields in such a way that it can: a) grasp the complexity of problems, b) take into account the diversity of life-world and scientific perceptions of problems, c) link abstract and case specific knowledge, and d) constitute knowledge and practices that promote what is perceived to be the common good.
(Pohl and Hirsch Hadorn, 2007, p. 20)
Transdisciplinary research projects consist of different phases of intra-, multi-, inter- or transdisciplinary collaborations (Herweg et al., 2012). The sequences and interactions of these different forms of collaboration need to be iteratively considered by the transdisciplinary team. For this process, aiming to tackle societal challenges and reaching academic success at the same time, several methods have been developed during the last few years (Pohl, 2018). The actors involved learn from each other (mutual learning) and they acquire a new type of learning (Tobias et al., 2019). As research on these actors themselves has shown, there are specific characteristics that are mandatory for being successful in transdisciplinary collaboration (Guimaràes et al., 2019).
Classical disciplinary knowledge is not sufficient in situations of high uncertainties like pastoralist societies facing complex social-ecological challenges (Seid et al., 2016). Hence, we require a dialogue with involved stakeholders as an extended peer community. Funtowicz and Ravetz (1993) introduced the term of ‘post-normal’ science as a concept transcending classical disciplinary academic science, engaging in a dialogue with all who have a stake in technical and normative decisions on problem solving. Transdisciplinary approaches are thus a central element of generating an added value of One Health, progressively strengthening cooperation between human and animal health and other disciplines, between academic and non-academic actors (Zinsstag et al., Chapter 2, this volume; Bunch and Waltner-Toews, Chapter 4, this volume). Next to post-normal sciences, analogous approaches to transdisciplinarity (that recognize the need to integrate disciplines and engage civil society in view of the relevance to the policy problem in question, but also recognize the complexity and uncertainty) are the Science of Team Science in North America, Integration and Implementation Sciences in Australia, and Public Engagement in Europe and elsewhere.
We can distinguish three forms of interdependent knowledge: (i) systems knowledge; (ii) target knowledge; and (iii) transformation knowledge. Systems knowledge relates to questions about the genesis and possible further development of a problem, and about interpretations of the problem in the life-world. Target knowledge relates to questions determining and explaining the need for change, desired goals and better practices, while transformation knowledge relates to questions about technical, social, legal, cultural and other possible means of acting that aim to transform existing practices and introduce desired ones (Pohl and Hirsch Hadorn, 2007). A transdisciplinary approach identifies and structures (providing an account of the state of disciplinary knowledge and actors in society involved in order to define the problem and raise research questions), analyses (providing adequate organization, and indicating which interests and circumstances to take into account) and brings results to fruition (embedding solutions into the social and scientific contexts, and testing the expected impact). Problem identification and structuring can overlap, which makes an iterative rather than a sequential approach more rational for achieving valid results. Unexpected and surprising results are to be expected (Hirsch Hadorn et al., 2008).
Scientists are often overwhelmed by the amount of information in everyday practice and the lack of a common language in specialized fields of expertise. In inter- and transdisciplinary programmes researchers should have: (i) their own in-depth knowledge; (ii) general knowledge of the other disciplines involved; (iii) social and communication skills for the exchange between disciplinary researchers and actors of the life-world; (iv) respect for others; and (v) teamwork and cognitive (or synthesis) skills (Flinterman et al., 2001). Thus, they need to have the mindset of a ‘transdisciplinarian’ (Guimaràes et al., 2019).
Additionally, awareness of the multilingualism within the transdisciplinary team is essential. Transdisciplinary projects mainly consist of actors with various mother tongues and different forms of multilingualism, which can be classified into three types in transdisciplinary collaborations (Pelikan, 2019; Pelikan et al., 2019):
1. Idiolect – Every person has an individual idiolect, consisting of, for instance, mother tongue, dialect and terminologies. This means multilingualism not only appears between and within individual languages, but also within all of us.
2. Intralingual multilingualism – The difference between the styles of thought (Pohl, 2011) and worldviews of the actors involved, leading to various concepts and values that are manifested in language(s) and communication, can only be successful if all involved actors share a defined set of values and concepts – in their individual language. Within every language (and also lingua franca), specific terms are used for all these values and concepts. In addition to the translations between individual languages, intralingual translations are necessary – translations within individual languages. A mindful hermeneutic approach is necessary to understand and translate these concepts into shared understandings between all the cultures, disciplines, etc. involved.
3. Interlingual multilingualism – In multicultural and multilingual and multidisciplinary contexts, the involved project members speak different languages (e.g. English and Spanish), which leads to multilingualism of different individual languages, interlingual multilingualism. Translations play an important role, and the need for a shared language is obvious. However, ‘as participants communicate in a common language, this may create the illusion that they also share a common culture’ (van Mulken and Hendriks, 2017). But the implementation of one individual language (e.g. English) as a shared language, a so-called lingua franca, does not create a shared culture and even causes further difficulties. Some transdisciplinary projects cannot find a lingua franca, as not all actors involved share one individual language (Münch, 2002), and translations into a lingua franca and between other languages are often underestimated since they also deal with intralingual multilingualism.
These types of multilingualism play an essential role in terms of comprehensibility of the communication of and within transdisciplinary projects. Monolingualism by using
