Jaroslav Peregrin

It seems that more and more people are behaving unreasonably: they hold opinions for which there is no reasonable justification; they are easily persuaded by nonsense and scorn the role of institutions that were established in modern societies precisely to convey real knowledge to us. This is currently causing increased interest among experts in logic, critical thinking, and argumentation theory, because these disciplines promise to provide us with tools for explicitly distinguishing reasonableness from unreasonableness. Unfortunately, these approaches often work with a concept of reason that is too simplified and can thus do injury to rationality. Therefore, in this text I want to address the question of whether logic (or something else) can provide us with some simple measure of rationality. I come to the conclusion that it cannot, that neither rationality (reasonableness) nor logic are simple concepts, and judging whether someone is behaving rationally can be a very complex problem.

This preprint has been accepted for publication in The Philosophical Journal. Please note, this preprint has not yet undergone final checks and typesetting. The final published version of this paper may, therefore, have slightly different content. The final version will be available via the ‘Peer-reviewed Publication DOI’ link in the related External link on this webpage. Please feel free to contact the author; we welcome feedback. Thank you. The article examines the nature of rationality and its relationship to logic in the context of contemporary concerns about conspiracy theories and the limits of critical thinking. It distinguishes between practical (instrumental) and theoretical rationality and questions the view that being rational simply means following the laws of logic. While theoretical rationality is linked to logical inference, research on cognitive biases shows that human reasoning systematically departs from formal logical ideals. The paper also challenges the idea of logical laws as objective, mind-independent structures, emphasizing the plurality of logical systems and the role of language in shaping inference. Logic is thus presented not as the discovery of timeless laws, but as an idealization of inferential practices rooted in natural language.

In his later writings Quine is increasingly explicit about the fact that his view of language is, in a certain sense, structuralistic. Structuralist interpretations of non-empirical, especially mathematical theories are now commonplace, but this chapter argues that Quine’s thought experiment with radical translation can be interpreted as showing that even empirical theories cannot be anchored in reality so firmly as to evade the same structuralist nature. Therefore, this peculiar form of structuralism extends to all our theories––the terms of all of them are best seen as meaning not definite substances, but nodes in certain structures. Moreover, radical translation shows––or purports to show––that the structure behind any natural language allows for some non-trivial ‘automorphisms’––that mapping the meaning of rabbit on that of undetached rabbit part, provided we make an appropriate remapping of many other meanings, does not change the language. Inscrutability of reference is then only a direct consequence.

What kind of logic could beings totally alien to us possess? Could it be an unexpected variation on our logic, e.g. with modus ponens replaced by affirming the consequent? In this paper, I argue that as no logic which has affirming the consequent in place of modus ponens can exist, the aliens’ logic cannot be exotic in this way. (Sure, the aliens could lack anything that we would call logic, but assuming they had a logic, it could not be too far-fetched vis-à-vis ours.) Moreover, I argue that our logical vocabulary has its function, and it must be such as to fulfill this function. This conclusion does not, I believe, tell us anything that is very profound about the (possible) aliens, but it does tell us something profound about logic itself.

The project of logic as a theoretical tool useful for the sciences and humanities involves, as a crucial step, logical formalization-the conversion of sentences of natural language to formulas of a formal language. But what do we do, exactly, when we do logical formalization? What are the criteria of adequacy of the conversion? In how far is logic normative? The paper offers answers to these central (but surprisingly rather neglected) questions and shows that getting a proper grasp on the process of formalization is important for understanding the nature of logic. The key point is that logic as a theoretical tool manages to consolidate our linguistic - in particular argumentative - practices by means of attaining a specific sort of reflective equilibrium. The paper provides a detailed discussion of the answers to the above questions implied by this understanding of logic. © 2016 Elsevier B.V., All rights reserved.

Göran Sundholm is well-known for his insistence that logic, to be pursued properly, requires a rich conceptual framework that in current logical theories is often, unfortunately, encountered in an essentially impoverished form. One of the conceptual distinctions he has been constantly urging is that between the various senses of consequence. I agree that logic needs a rich conceptual framework, and that especially with respect to consequence many crucial distinctions must be maintained. However, these for me are not quite the same as those urged by Göran (at least not obviously so), and in this paper I explain which I think the distinctions should be and why they are crucial. This, I hope, may lead to comparing notes with Göran; which, I believe, may yield some interesting results.

This is a précis of my book _Normative species._ The point of departure of the book is inferentialism – the doctrine foreshadowed by Sellars and brought to full fruition by Robert Brandom, according to which language, but also other specifically human amenities, presuppose rules or are directly decomposable into various complexes of rules. It seems, indeed, that rules have managed to erect spaces within which we humans assumed our “unnatural” forms of life and which differentiate us so much from other animals. From this viewpoint, rules and complexes of rules start to look as something like the true key to our peculiar nature.

We know that lots of things are correct. (Helping people in need is correct. Moving the bishop diagonally when playing chess is correct. Adding 7 to 5 to make 12 is correct.) But where does this correctness come from? I argue that correctness is best seen as something we humans created in the process of forming our societies. This, admittedly, is speculative; but aside of this, there are facts that are more than speculations. In particular, I argue that our correctness is based on normative attitudes, though these often determine only the criteria of correctness, letting the criteria to then determine what is correct independently of our will. Thus it holds both that correctness is wholly our creation and that it is independent of us in the sense that things may be correct even if we do not know that they are (or, indeed, think them incorrect).

Kniha Tomáše Marvana přehledným způsobem rekapituluje filosofické diskuse, které se odehrávaly a odehrávají na půdě tzv. „postanalytické“ filosofie na téma realismus vs. relativismus; a je pokusem o jejich kritické zhodnocení. Jde o nesporně zajímavou a užitečnou knihu; v tomto textu však argumentuji, že realismus, z jehož pozic Marvan svou kritiku vede, není neproblematický. Zdá se mi, že Marvan zaměňuje prokázání nemožnosti vyvrátit realismus za prokázání relativismu; přičemž podle mne je tato nemožnost jenom důsledkem toho, že celá diskuse realismus vs. relativismus je pochybená.

I propose that logic may be seen as a science of patterns—however, not in the sense in which mathematics is a science of patterns, but rather in the sense in which physics is. The proposal is that logic identifies, explores, and fixes the inferential patterns which de facto govern our argumentative practices. It can be seen, I argue, as picking up the patterns and working from them toward the state of reflective equilibrium, where the laws it aims at are explicitly articulated. Due to the normativity of logic, this process is not quite the same as that in which a natural science works its way from data to its laws; however, there is no reason why it should be seen as proceeding via a mysterious "a priori analysis.” Instead, it should proceed in the intersubjective space in which the sciences are practiced.