Jens Kipper

Many have argued that there is something that is a priori about all necessary truths, including a posteriori necessities. According to a particularly popular claim of this kind, one can know a priori whether a sentence is G-necessary, i.e. whether it is either necessarily true or necessarily false. In this paper, I identify the most plausible version of this claim and I argue that it fails. My discussion also reveals, and depends upon, an important feature of putative natural kind terms that has been widely overlooked. I conclude by outlining a proposal of what is really a priori about necessities.

According to epistemic two-dimensionalism, or simply two-dimensionalism, linguistic expressions are associated with two intensions, one of which represents an expression’s a priori implications. The author investigates the prospects of conceptual analysis on the basis of a two-dimensionalist theory of meaning. He discusses a number of arguments for and against two-dimensional semantics and argues that properly construed, two-dimensionalism provides a potent and plausible account of meaning. Against the background of this account, the author then goes on to assess the value of conceptual analysis in philosophical practice, outlining its goals, its promises, but also its limitations.

In light of the problem of logical omniscience, some scholars have argued that belief is question-sensitive: agents don't simply believe propositions but rather believe answers to questions. Hoek (2022) has recently developed a version of this approach on which a belief state is a "web" of questions and answers. Here, we present several challenges to Hoek's question-sensitive account of belief. First, Hoek's account is prone to very similar logical omniscience problems as those he claims to address. Second, the link between belief and action he proposes is too rigid. We close by sketching a generalization of the account that can meet these challenges.

Philosophen berufen sich in Gedankenexperimenten oft auf Intuitionen. Doch werden diese Intuitionen auch von anderen Philosophen oder von philosophischen Laien geteilt? Und durch welche Faktoren werden sie eigentlich bestimmt? Experimentelle Philosophen gehen solchen Fragen seit einigen Jahren mit empirischen Methoden auf den Grund. Ihre Ergebnisse sind mitunter verblüffend und haben für Aufsehen gesorgt. Der vorliegende Band lässt führende Vertreter und Gegner dieser wachsenden Bewegung zu Wort kommen und will die bislang überwiegend englischsprachige Debatte verstärkt in die deutsche Philosophie hineintragen.

In this paper, we offer a novel defense of descriptivism about reference. Our argument is based on principles about the relevance of speaker intentions to reference that are shared by many opponents of descriptivism, including Saul Kripke. We first show that two such principles that are plausibly endorsed by Kripke and other prominent externalists in fact entail descriptivism. The first principle states that when certain kinds of speaker intentions are present, they suffice to determine and explain reference. According to the second principle, certain speaker intentions must be present whenever something determines or explains reference. We then go on to make these principles more precise and argue that it would be costly to deny either of them. Since on the more precise understanding we suggest, the conjunction of these principles still entails descriptivism, we conclude that opponents of descriptivism have to give up some highly plausible assumption about the relation between speaker intentions and reference.

In the essay, I compare the aims and especially the methods of philosophers and grammarians. It transpires that there are several interesting similarities to be found with the method and aim in particular of traditional 'armchair philosophers'. I argue that these similarities go far enough to suggest that if armchair philosophers' method is in a state of challenge, as is claimed by a number of experimental philosophers, then the same can be said about the method of grammarians. However, I also try to show that it is not easy for experimental philosophers to frame their critique in a way that avoids construing its target too broadly, which would lead to unacceptable consequences. I conclude with some brief remarks on the extent to which a properly targeted critique can provide a challenge for traditional philosophical method

According to the modal account of propositional apriority, a proposition is a priori if it is possible to know it with a priori justification. Assuming that modal truths are necessarily true and that there are contingent a priori truths, this account has the undesirable consequence that a proposition can be a priori in a world in which it is false. Epistemic two-dimensionalism faces the same problem, since on its standard interpretation, it also entails that a priori propositions are necessarily a priori. In response to this problem, Chalmers and Rabern propose an alternative conception of propositional apriority as well as two-dimensional truth-conditions for apriority statements. Their proposal is also supposed to avoid another problem for the modal account, namely that it entails the existence of false instances of ‘φ iff actually φ’. I discuss Chalmers and Rabern’s account and point out a number of problems with it. I then develop my own account of propositional apriority that solves the problems in question, that can be accepted by friends and foes of two-dimensionalism alike, and that is also neutral with respect to the question of how one construes the objects of propositional apriority.

The main goal of my paper is to argue that data compression is a necessary condition for intelligence. One key motivation for this proposal stems from a paradox about intuition and intelligence. For the purposes of this paper, it will be useful to consider playing board games—such as chess and Go—as a paradigm of problem solving and cognition, and computer programs as a model of human cognition. I first describe the basic components of computer programs that play board games, namely value functions and search functions. I then argue that value functions both play the same role as intuition in humans and work in essentially the same way. However, as will become apparent, using an ordinary value function is just a simpler and less accurate form of relying on a database or lookup table. This raises our paradox, since reliance on intuition is usually considered to manifest intelligence, whereas usage of a lookup table is not. I therefore introduce another condition for intelligence that is related to data compression. This proposal allows that even reliance on a perfectly accurate lookup table can be nonintelligent, while retaining the claim that reliance on intuition can be highly intelligent. My account is not just theoretically plausible, but it also captures a crucial empirical constraint. This is because all systems with limited resources that solve complex problems—and hence, all cognitive systems—need to compress data.

It has long been known that the popular account of egocentric thoughts developed by David Lewis is in conflict with a natural account of communication, according to which successful communication requires the transmission of a thought content from speaker to hearer. In this paper, I discuss a number of proposed attempts to reconcile these two accounts of egocentric thought and communication. Each of them postulates two kinds of mental content, where one is egocentric, and the other is transmitted from speaker to hearer in communication. I argue that Ninan’s account, which involves multi-centered contents, and Kölbel’s and Moss’s accounts, which postulate centered and uncentered proxy contents, respectively, are unsatisfactory. Therefore, I propose a two-dimensionalist account, according to which egocentric thoughts are represented by primary intensions, while the thoughts shared by speaker and hearer in cases of successful communication are represented by secondary intensions. Finally, I argue that aside from being able to reconcile Lewis’s account of egocentric thoughts with the natural account of communication, two-dimensionalism also provides the means for modeling agreement and disagreement.

In his earlier writings, Fred Dretske proposed an anti-skeptical strategy that is based on a rejection of the view that knowledge is closed under known entailment. This strategy is seemingly congenial with a sensitivity condition for knowledge, which is often associated with Dretske’s epistemology. However, it is not obvious how Dretske’s early account meshes with the information-theoretic view developed in Knowledge and the Flow of Information. One aim of this paper is to elucidate the connections between these accounts. First I argue that, contrary to an objection raised by Christoph Jäger, the information-theoretic account is compatible with Dretske’s anti-skeptical strategy based on the rejection of closure. This strategy invokes the notion of channel conditions, which are roughly speaking those conditions that are necessary and jointly sufficient for a signal to carry information. I propose an interpretation of the account that is based on the idea that a signal’s carrying information requires that the channel conditions are stable. It is shown that the resulting account incorporates both a sensitivity condition and a safety condition for knowledge. Finally, I demonstrate how this proposal allows for knowledge of modally robust propositions without making its acquisition too easy, as simple safety accounts do. I end with a suggestion concerning the direction that future research should take, based on the fact that in its present form the information-theoretic account does not capture inferential knowledge.

This paper critically examines Timothy Williamson’s claim that knowledge figures essentially in explanations of behavior. Since this claim implies that knowledge is causally efficacious in bringing about actions, it plays a key role in Williamson’s case for knowledge being a mental state. I first discuss a central example of Williamson, in which a burglar ransacks a house. I dispute Williamson’s claim that the best explanation of the burglar’s behavior invokes the burglar’s state of knowledge as he enters the house, by arguing that there is a better explanation that only mentions the burglar’s beliefs. Since the reasons that explain the superiority of my proposed explanation generalize, I conclude that one does not have to invoke a subject’s state of knowledge to explain behavior. Nevertheless, Williamson’s explanation is superior to belief-based explanations if one only considers facts that obtain before the action takes place. In the final part of the paper, I argue that this fact does not help Williamson’s case for considering knowledge as a mental state.

In this paper, I examine how nudges affect the autonomy and freedom of those nudged. I consider two arguments put forth by Thaler and Sunstein for the claim that these effects can only be minor. According to the first of these arguments, nudges cannot significantly restrict a person’s autonomy or freedom since they are easy to resist. According to the second argument, the existence of nudges is inevitable, and thus, pursuing libertarian paternalism by nudging people doesn’t make a relevant difference to people’s autonomy and freedom. After arguing that both of these arguments fail, I elucidate the general conditions in which, and the degrees to which, a person’s autonomy and freedom are affected by nudges. One focus of this discussion concerns how people’s autonomy and freedom are affected if—for example, due to progress in information technology—nudges become more effective, more individualized and more common, and affect more people.

In this paper, I identify and discuss the following feature of our judgments about hypothetical scenarios concerning the identity of persons: with respect to the vast majority of scenarios, both members of a pair of logically complementary propositions about personal identity are conceivable. I consider a number of explanations of this feature that draw on the metaphysics and the epistemology of personal identity, none of which prove to be satisfactory. I then argue that in order to give an adequate explanation, one needs to recognize an important characteristic of our concept of personal identity: it is such that if there are mental substances (or the like), they constitute personal identity. At the same time, there can still be persons if there are no such substances. Since this finding casts doubts on the way that thought experiments about personal identity are usually set up, I end by outlining its potential consequences for the debate over the identity of persons.

In this paper, I argue that, contrary to Robert Stalnaker’s highly influential account of linguistic communication, successful communication does not depend on a common ground between speaker and hearer. The problem for Stalnaker’s account manifests itself in communicative situations that represent both Lingens cases, i.e., cases involving egocentric beliefs, and Frege cases, i.e., cases involving identity confusions. I describe two hypothetical cases that involve successful communication, but in which no common ground of the kind required by Stalnaker’s account is available. I therefore propose an alternative account of communication that is based on epistemic two-dimensionalism. This account maintains that communication requires the transfer of a thought content from speaker to hearer. By holding that this shared content often constitutes common ground, it preserves much of the appeal of Stalnaker’s account. However, my account allows for cases in which the shared thought content does not figure in common ground.

Chalmers has argued that Bayesianism supports the existence of a priori truths, since it entails that scrutability conditionals are not rationally revisable. However, as we argue, Chalmers's arguments leave open that every proposition is rationally deniable, which would be devastating for large parts of his philosophical program. We suggest that Chalmers should appeal to well-known convergence theorems to argue that ideally rational subjects converge on the truth of scrutability conditionals. However, our discussion reveals that showing that these theorems apply in effect requires assuming scrutability. Consequently, Bayesianism doesn't conflict with Chalmers's scrutability framework, but it doesn't support it, either.

A recent approach to the problem of logical omniscience holds that belief is question-sensitive: what an agent believes depends on what question they try to answer (Pérez Carballo, 2016; Yalcin, 2018; Hoek, 2022). While the question-sensitive approach can avoid some logical omniscience problems, we argue that it suffers from nearby problems. First, these accounts all validate closure principles that are just as implausible as the ones it was designed to avoid. Second, question-sensitivity by itself isn’t suitable for explaining many kinds of failures of logical omniscience. Recognizing the flaws of this approach, however, naturally leads to a more promising solution. Our account generalizes the question-sensitive approach by appealing to (1) the defeasible nature of dispositions toward action associated with belief and (2) the algorithms an agent uses to make decisions. On our view, then, believing that φ means being disposed to employ an algorithm which outputs acting on the information that φ in normal circumstances associated with φ. We argue that this account naturally generalizes the question-sensitive accounts while avoiding their faults.

The epistemic arrow of time is the fact that our knowledge of the past seems to be both of a different kind and more detailed than our knowledge of the future. Just like with the other arrows of time, it has often been speculated that the epistemic arrow arises due to the second law of thermodynamics. In this paper, we investigate the epistemic arrow of time using a fully formal framework. We begin by defining a memory system as any physical system whose present state can provide information about the state of the external world at some time other than the present. We then identify two types of memory systems in our universe, along with an important special case of the first type, which we distinguish as a third type of memory system. We show that two of these types of memory systems are time-symmetric, able to provide knowledge about both the past and the future. However, the third type of memory systems exploits the second law of thermodynamics, at least in all of its instances in our universe that we are aware of. The result is that in our universe, this type of memory system only ever provides information about the past. We also argue that human memory is of this third type, completing the argument. We end by scrutinizing the basis of the second law itself. This uncovers a previously unappreciated formal problem for common arguments that try to derive the second law from the “Past Hypothesis”, i.e., from the claim that the very early universe was in a state of extremely low entropy. Our analysis is indebted to prior work by one of us but expands and improves upon this work in several respects.

Künstliche Intelligenz (KI) ist heute schon ein fester Bestandteil unseres Lebens, auch wenn sie oft im Verborgenen wirkt. Wo wird diese Entwicklung hinführen und was wird das für uns bedeuten? Jens Kipper erklärt, wie moderne KI funktioniert, was sie heute schon kann und welche Auswirkungen ihre Verwendung in Waffensystemen, in der Medizin und Wissenschaft, im Arbeitsleben und anderswo haben wird. Kipper argumentiert dafür, dass die Entwicklung von KI zu großen gesellschaftlichen Umwälzungen führen wird. Er erläutert zudem, wovon es abhängt, dass diese Umwälzungen erfreulicher Natur sein werden und was wir tun können, um die durch den Einsatz von KI geprägten Veränderungen in die richtige Richtung zu lenken.