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.

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.

There is a clear sense in which logic is a theory of our “game of giving and asking for reasons” (GOGAR): logical laws articulate its most general principles. The usual picture is that people play GOGAR and logicians act as supervisors, confirming that some of the inferences that constitute the moves of the game are correct, while pointing out that others are incorrect. To justify such supervision, logicians require some authority to underpin their arbitration of what is correct. Where could this authority stem from? The usual answer is that it stems from the fact that logical laws reflect some fixed structures either of the human mind or of the natural world. My claim, in contrast, is that the ultimate source of any such authority stems directly from the argumentative practices themselves, viz., from the norms inherent in them, which logic brings to light (and neatens).

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.

Discussions on the compositionality of inferential roles concentrate on extralogical vocabulary. However, there are nontrivial problems concerning the compositionality of sentences formed by the standard constants of propositional logic. For example, is the inferential role of A ∧ B uniquely determined by those of A and B? And how is it determined? This paper investigates such questions. We also show that these issues raise matters of more significance than may prima facie appear.

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.

Recent decades are marked by the upswing of the use of the term "normativity" not only in philosophical discussions, but increasingly also within reports of empirical scientists. This may invoke the question how far these developments overlap and in how far they go past each other. A significant overlap might lead to an interesting coalescence of the two approaches to norms, which may provide for a "naturalization" of some philosophical speculations about normativity, putting them on a firmer foundation, while offering the empirical scientists some new impulses for directing their research. In this paper I give an overview of some recent empirical results concerning human normativity and I point out a certain philosophical tradition, rooted especially in the works of Wittgenstein, Sellars and Brandom, which treats normativity so that it becomes more or less compatible with these results.

In a paper published in this journal Reinikainen (forthcoming) argues that my version of inferentialism “faces a problem concerning the determination of linguistic meaning”, which “essentially emerges from troubles in understanding, in inferentialist terms, how the world is ‘embodied’ in language”. As far as I can see, his argument is based on a misunderstanding of what my inferentialism amounts to. I explain what I mean.

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).