Aufgeklärtes Eigeninteresse. Eine Theorie theoretischer und praktischer Rationalität [Enlightened Self-Interest. A Theory of Theoretical and Practical Rationality]

The subject of my dissertation is "rationality". In this book I undertake a comprehensive, systematic and independent treatment of the problem of rationality. This furthers progress toward a general theory of rationality, one that represents and defends a uniform conception of reason. The structure and general outline are as follows: Part I: General Definition of the Concept; Part II: Rationality in the Theoretical Realm; Part III: Rationality in the Practical Realm (parts II and III are divided respectively into A. Relative Reasons and B. Absolute Reasons); Part IV: Grounds for the Principle of Reason. My aim in this work is to prove that a conception of rationality as justification of our usage of language is more significant than has been classically recognized, without, however, reducing the concept of rationality. After a definition of the term is provided in the first chapter by means of language analysis, the following three questions are dealt with in the subsequent chapters: a) Exhaustion of rationality in relative reasons—i.e., is reasoning exhausted by reference to existing views and goals, or does rationality also exist in a strong sense? The latter would be the case if the views and goals referred to the relative conception must themselves be justified de novo. I argue that such an absolute justification of views and goals cannot be provided. To this end, in the theoretical domain, I discuss a question prominent in the debate over the rationality of worldviews, namely the question of whether the standards of theoretical rationality are merely culturally relative (chapter V.). Here I arrive at the position that standards of theoretical rationality are only transcultural insofar as there are goals which are not themselves culturally-dependent. With regard to practically fundamental goals, the core standards of modern science can be justified. This justification strategy therefore requires that such goals be established. In practical terms, first I address (in Chapter VII) the so-called "final justification" of norms problem. Here I discuss above all the transcendental-pragmatic proposal and the contractualist conception. According to my view, neither succeed in providing a final rational grounding for norms. That grounding pertains instead to the rationale for objectives, and Chapter VIII demonstrates that even a final justification of objectives is impossible. This does not mean, however, that a person's goals cannot be criticized as irrational. But the warrant in this case depends on the rules that govern the genesis of desires being accepted by the subject. b) If substantive rationality does not exist because no absolute grounding for opinions and goals can obtain, then the question of how strong or weak the concept of rationality is acquires further weight. On that basis, relative theoretical and practical rationality is examined in detail. I aim with this analysis of (relative) rationality to apprehend the structural parallelism between rationality in both the practical and the theoretical domain, and therefore to defend a uniform conception of reason or rationality. This is accomplished by identifying a concept that exhibits the same structure in both theoretical and practical domains: the term "rational" is applied to actions and opinions in order to claim, first of all, that they are "well-founded." For example, one must inquire into the precise rational justification for opinions or actions. To determine the individually necessary and jointly sufficient conditions required for an opinion or action to be rational, one must first provide a formal characterization of the rationality of those opinions or actions. What is to count as a rational ground can only be explained by formal procedures and results achievable via those procedures. To be more specific, I claim that the process of opinion formation and practical reflection is subject to rational justification based on internalist rules. The rules governing theoretical rationality can have their content transformed in a further move, if one takes the result of the process of rational opinion-formation as the product of an epistemological determination, that is, as a decision about which opinion to hold that is made on the basis of epistemological or prudential goals. Implicit in this position is the controversial idea that one can actually decide to believe something. The rules of practical reason are the rules that guide the rational selection of objectives and actions. The structural parallelism of theoretical and practical rationality consists, therefore, in the fact that both refer to mental processes that are controlled by rules which one freely accepts and follows. In both cases, these rules are to be understood as governing the rational choice of a mental or physical action. c) Therefore, the question of whether rationality—being rational—can in turn be grounded by reasons can be answered in the following way: The rules of rationality can only be justified with reference to a person’s goals, as the best strategy for achieving those goals. If someone does not desire the optimal realization of his goals, there is no other way of arguing directly for rationality. One can only attempt to demonstrate—if the person is open to argument—that it is typically in the person's own best interest to adhere to the rules of rationality