This paper proves a precisification of Hume’s Law—the thesis that one cannot get an ought from an is—as an instance of a more general theorem which establishes several other philosophically interesting, though less controversial, barriers to logical consequence.

In 1954, A. N. Prior discovered a way to formalize tense-logic—as such, there is no doubt that he is the father of modern tense-logic. Despite this, he considered his early teacher in p...

This monograph proposes a new way of implementing interaction in logic. It also provides an elementary introduction to Constructive Type Theory. The authors equally emphasize basic ideas and finer technical details. In addition, many worked out exercises and examples will help readers to better understand the concepts under discussion. One of the chief ideas animating this study is that the dialogical understanding of definitional equality and its execution provide both a simple and a direct way of implementing the CTT approach (...) within a game-theoretical conception of meaning. In addition, the importance of the play level over the strategy level is stressed, binding together the matter of execution with that of equality and the finitary perspective on games constituting meaning. According to this perspective the emergence of concepts are not only games of giving and asking for reasons, they are also games that include moves establishing how it is that the reasons brought forward accomplish their explicative task. Thus, immanent reasoning games are dialogical games of Why and How. (shrink)

This paper explores early Australasian philosophy in some detail. Two approaches have dominated Western philosophy in Australia: idealism and materialism. Idealism was prevalent between the 1880s and the 1930s, but dissipated thereafter. Idealism in Australia often reflected Kantian themes, but it also reflected the revival of interest in Hegel through the work of ‘absolute idealists’ such as T. H. Green, F. H. Bradley, and Henry Jones. A number of the early New Zealand philosophers were also educated in the idealist tradition (...) and were influential in their communities, but produced relatively little. In Australia, materialism gained prominence through the work of John Anderson, who arrived in Australia in 1927, and continues to be influential. John Anderson had been a student of Henry Jones, who might therefore be said to have influenced both main strands of Australian philosophical thought. (shrink)

A critical survey of various positions on the nature, use, possession, and analysis of normative concepts. We frame our treatment around G.E. Moore’s Open Question Argument, and the ways metaethicists have responded by departing from a Classical Theory of concepts. In addition to the Classical Theory, we discuss synthetic naturalism, noncognitivism (expressivist and inferentialist), prototype theory, network theory, and empirical linguistic approaches. Although written for a general philosophical audience, we attempt to provide a new perspective and highlight some underappreciated problems (...) about normative concepts. (shrink)

Moral theories usually aspire to be explanatory – to tell us why something is wrong, why it is good, or why you ought to do it. So it is worth knowing how moral explanations differ, if they do, from explanations of other things. This paper uncovers a common unarticulated theory about how normative explanations must work – that they must follow what I call the Standard Model. Though the Standard Model Theory has many implications, in this paper I focus primarily (...) on only one. It plays a crucial role in an argument originally due to Cudworth that has been widely held to conclusively establish that voluntaristic ethical theories are incoherent. But if Cudworth’s argument works, then so would similar arguments against many other moral theories. All of these theories therefore need a different model for how normative explanations can work. So I also motivate and sketch one such alternative model. The result enables us to make progress in evaluating the prospects for a successful reductive view about the normative. (shrink)

Survey article on Naturalism dealing with Hume's NOFI (including Prior's objections), Moore's Naturalistic Fallacy and the Barren Tautology Argument. Naturalism, as I understand it, is a form of moral realism which rejects fundamental moral facts or properties. Thus it is opposed to both non-cognitivism, and and the error theory but also to non-naturalism. General conclusion: as of 1991: naturalism as a program has not been refuted though none of the extant versions look particularly promising.

Besides pure declarative arguments, whose premises and conclusions are declaratives (“you sinned shamelessly; so you sinned”), and pure imperative arguments, whose premises and conclusions are imperatives (“repent quickly; so repent”), there are mixed-premise arguments, whose premises include both imperatives and declaratives (“if you sinned, repent; you sinned; so repent”), and cross-species arguments, whose premises are declaratives and whose conclusions are imperatives (“you must repent; so repent”) or vice versa (“repent; so you can repent”). I propose a general definition of argument (...) validity: an argument is valid exactly if, necessarily, every fact that sustains its premises also sustains its conclusion, where a fact sustains an imperative exactly if it favors the satisfaction over the violation of the imperative, and a fact sustains a declarative exactly if, necessarily, the declarative is true if the fact exists. I argue that this definition yields as special cases the standard definition of validity for pure declarative arguments and my previously defended definition of validity for pure imperative arguments, and that it yields intuitively acceptable results for mixed-premise and cross-species arguments. (shrink)

For much of the first fifty years of its existence, analytic philosophy shunned discussions of normativity and ethics. Ethical statements were considered as pseudo-propositions, or as expressions of pro- or con-attitudes of minor theoretical significance. Nowadays, in contrast, prominent analytic philosophers pay close attention to normative problems. Here we focus our attention on the work of Searle, at the same time drawing out an important connection between Searle’s work and that of two other seminal figures in this development: H.L.A. Hart (...) and John Rawls. We show that all three thinkers tend to assume that there is but one type of normativity within the realm of social institutions – roughly, the sort of normativity that is involved in following the results of chess – and that they thereby neglect features that are of crucial significance for an adequate understanding of social reality. (shrink)

It doesn’t seem possible to be a realist about the traditional Christian God while claiming to be able to reduce God talk in naturalistically acceptable terms. Reduction, in this case, seems obviously eliminativist. Many philosophers seem to think that the same is true of the normative—that reductive “realists” about the normative are not really realists about the normative at all, or at least, only in some attenuated sense. This paper takes on the challenge of articulating what it is that makes (...) reductive theological realism look hopeless, with the aim of explaining why we should think that the normative is relevantly different. Although it follows from my diagnosis that reductivists have their work cut out for them, I find nothing which suggests that the prospects for a successful reductive realism about the normative are in any way diminished—particularly for reductive views about reasons. Even reductivists, I argue, can at least aspire to a realism that is robust. (shrink)

Imperatives cannot be true or false, so they are shunned by logicians. And yet imperatives can be combined by logical connectives: "kiss me and hug me" is the conjunction of "kiss me" with "hug me". This example may suggest that declarative and imperative logic are isomorphic: just as the conjunction of two declaratives is true exactly if both conjuncts are true, the conjunction of two imperatives is satisfied exactly if both conjuncts are satisfied—what more is there to say? Much more, (...) I argue. "If you love me, kiss me", a conditional imperative, mixes a declarative antecedent ("you love me") with an imperative consequent ("kiss me"); it is satisfied if you love and kiss me, violated if you love but don't kiss me, and avoided if you don't love me. So we need a logic of three -valued imperatives which mixes declaratives with imperatives. I develop such a logic. (shrink)

The two dogmas at issue are the Humean dogma that “‘is’ statements do not imply ‘ought’ statements” and the Kantian dogma that “‘ought’ statements imply ‘can’” statements. The extant literature concludes these logically contradict each other. On the contrary, it is argued here that while there is no derivable formal contradiction, the juxtaposition of the dogmas manifests a philosophical disagreement over how to understand the logic of prescriptions. This disagreement bears on how to understand current metaethical debate between realists and (...) non-realists about morality in a way not heretofore investigated. The conclusion is that realists have the resources to account for both dogmas, while non-realists, if they strictly adhere to the “is”/“ought” gap, cannot give an adequate account of why “ought” implies “can”. (shrink)

§13 of Principia Ethica contains G. E. Moore’s most famous open question arguments. Several of Moore’s contemporaries defended various forms of metaethical nonnaturalism—a doctrine Moore himself endorsed—by appeal to OQAs. Some contemporary cognitivists embrace the force of Moore’s OQAs against metaethical naturalism. And those who posit noncognitivist meaning components of ethical terms have traditionally used OQAs to fuel their own emotivist, prescriptivist, and expressivist metaethical programs. Despite this influence, Moore’s OQAs have been ridiculed in recent decades. Their deployment has been (...) labeled “accident prone,” “simple to dismiss,” and just plain invalid. Critics accuse Moore of begging the question. Others argue that his OQAs founder upon the paradox of analysis. And still others argue that Moore’s open question argumentation is incompatible with the Kripke–Putnam causal theory of reference and thus it “simply fails; it is bankrupt”. I aim to show that there is something of continuing value in Moore’s open question efforts. I present and criticize Nicholas Sturgeon’s influential interpretation of Moore’s OQAs as a means to motivate and explicate my own interpretation of Moore’s thoughts in §13 of Principia Ethica. I then articulate the role that OQAs are intended to play in Moore’s overall argumentative strategies to undermine metaethical naturalism and thereby provide some theoretical support for metaethical nonnaturalism. Finally, I attend to the most prominent objections to Moore’s theorizing and attempt to evaluate the extent to which Moore’s efforts are successful. My hope is to display both the promising portions of Moore’s metaethical argumentation in Principia Ethica as well as its limitations. (shrink)

This paper contains an analysis of performatives with special attention to performatives in the law. It deals with the possibility to recognise performativity by means of a grammatical-syntactic criterion, the self-verifying and norm-promulgating character of legal performatives, an analysis of the effects of performatives by means of causal logic, the different forms of performativity and a theory of promise-performatives.

On the historic Cross, it is God Himself Who has actually met the last dark limits of our life, and has brought Himself face to face with that inescapable something (or Someone) which seems to keep us forever strangers (physically, morally, logically and in every other way) to the Absolute and Eternal. And because it is God Himself Who has thus in life and in death personally encountered sin, death, time and corruption, He has overthrown them and raised and transformed (...) the existence that is subject to them, our existence, into the glorious Being of His Everlasting Godhead. He has robbed death of its sting and the grave of its victory, and delivered us from Satan's ancient power. A.N. Prior: Athanasius Contra Mundum. Prior (1934). (shrink)

Besides pure declarative arguments, whose premises and conclusions are declaratives, and pure imperative arguments, whose premises and conclusions are imperatives, there are mixed-premise arguments, whose premises include both imperatives and declaratives, and cross-species arguments, whose premises are declaratives and whose conclusions are imperatives or vice versa. I propose a general definition of argument validity: an argument is valid exactly if, necessarily, every fact that sustains its premises also sustains its conclusion, where a fact sustains an imperative exactly if it favors (...) the satisfaction over the violation proposition of the imperative, and a fact sustains a declarative exactly if, necessarily, the declarative is true if the fact exists. I argue that this definition yields as special cases the standard definition of validity for pure declarative arguments and my previously defended definition of validity for pure imperative arguments, and that it yields intuitively acceptable results for mixed-premise and cross-species arguments. (shrink)

What is it that is doing the real work in Prior’s 1949 book Logic and the Basis of Ethics? As Prior’s title announces, it seems that the answer is logic. But what exactly does this mean to Prior?

It has frequently been lamented that while the human species has made immense progress in science it is nevertheless ethically backward. This ethical backwardness is all the more dangerous because the advanced state of scientific knowledge has made available a technology with which we are able to destroy ourselves—indeed a technology which may have got so much out of hand that we may not even have the capacity to prevent it from destroying us.

Purpose – The purpose of this paper is to explore artificial moral agency by reflecting upon the possibility of a Moral Turing Test and whether its lack of focus on interiority, i.e. its behaviouristic foundation, counts as an obstacle to establishing such a test to judge the performance of an Artificial Moral Agent. Subsequently, to investigate whether an MTT could serve as a useful framework for the understanding, designing and engineering of AMAs, we set out to address fundamental challenges within (...) the field of robot ethics regarding the formal representation of moral theories and standards. Here, typically three design approaches to AMAs are available: top-down theory-driven models and bottom-up approaches which set out to model moral behaviour by means of models for adaptive learning, such as neural networks, and finally, hybrid models, which involve components from both top-down and bottom-up approaches to the modelling of moral agency. With inspiration from Allen and Wallace as well as Prior, we elaborate on theoretically driven approaches to machine ethics by introducing deontic tense logic. Finally, within this framework, we explore the character of human interaction with a robot which has successfully passed an MTT. Design/methodology/approach – The ideas in this paper reflect preliminary theoretical considerations regarding the possibility of establishing a MTT based on the evaluation of moral behaviour, which focusses on moral reasoning regarding possible actions. The thoughts reflected fall within the field of normative ethics and apply deontic tense logic to discuss the possibilities and limitations of artificial moral agency. Findings – The authors stipulate a formalisation of logic of obligation, time and modality, which may serve as a candidate for implementing a system corresponding to an MTT in a restricted sense. Hence, the authors argue that to establish a present moral obligation, we need to be able to make a description of the actual situation and the relevant general moral rules. Such a description can never be complete, as the combination of exhaustive knowledge about both situations and rules would involve a God eye’s view, enabling one to know all there is to know and take everything relevant into consideration before making a perfect moral decision to act upon. Consequently, due to this frame problem, from an engineering point of view, we can only strive for designing a robot supposed to operate within a restricted domain and within a limited space-time region. Given such a setup, the robot has to be able to perform moral reasoning based on a formal description of the situation and any possible future developments. Although a system of this kind may be useful, it is clearly also limited to a particular context. It seems that it will always be possible to find special cases in which a given system does not pass the MTT. This calls for a new design of moral systems with trust-related components which will make it possible for the system to learn from experience. Originality/value – It is without doubt that in the near future we are going to be faced with advanced social robots with increasing autonomy, and our growing engagement with these robots calls for the exploration of ethical issues and stresses the importance of informing the process of engineering ethical robots. Our contribution can be seen as an early step in this direction. (shrink)

This paper revisits Richard Price’s Review of the Principal Questions in Morals. Price was a defender of rationalism about ethics and he anticipated many views and arguments that became influential as the metaethical and ethical debates evolved over the later centuries. The paper explores and assesses Price’s arguments in favour of rationalism and against sentimentalism, with a view to how they bear on the modern metaethical debate.

ZusammenfassungDem sogenannten Knobe-Effekt zufolge bestimmt die moralische Valenz von Nebeneffekten menschlichen Verhaltens die Zuschreibung ihrer absichtlichen Verursachung. Wir argumentieren, dass erstens die empirisch ermittelten sozialpsychologischen Daten den Knobe-Effekt in der üblichen Lesart nicht belegen, vor allem wegen der unvollständigen Untersuchung der entscheidenden moralischen Varianzfaktoren. Zweitens zeigen wir, dass - und wie - eine spezifische Version des traditionellen Prinzips des Doppeleffekts den empirisch bestätigten Teil des Knobe-Effekts philosophisch erklärt. Die Erklärungskraft des Prinzips des Doppeleffekts kann auch als eine Rechtfertigung eben dieses (...) Prinzips gesehen werden. (shrink)

Moral reductionist believes that the reality of moral qualities are the same qualities which can be expressed with immoral words. Such an ontological view has an epistemological aspect which states our understanding of moral facts is either our understanding of immoral facts or our deductions of immoral understanding. From moral reductionists and especially the naturalists’ point of view, the ability to explain moral knowledge without resorting to some theories such as moral intuition is considered to be an important advantage and (...) even a strong reason for their view. Therefore, the present paper is going to study the reductionistic explanations about moral knowledge and justifications of moral believes. We have come to the conclusion that among the explanations presented by the naturalists, analytic knowledge has the same problems which have discredited the theory of analytic reductionism. Also, deducing value from non-value is either facing the logical gap of is-must; or if there is a meaningful descriptive-valuable link, we can’t finally come to unconditional moral results. (shrink)

Bartley’s pancritical rationalism is seen by some as being a refinement of Popper’s critical rationalism. I contest this view and argue that pancritical rationalism is obtained from critical rationalism by removing some of its most important and useful features. The remainder consists of a restatement of some of Popper’s key ideas and an interpretation of others that I attempt to show is not entirely faithful to what Popper says.

Arthur Prior was one of the logicians who participated in the invention of the possible worlds’ semantics. The ontology, which is connected with his systems of modal logic, is unique. Prior tried to reduce the number of abstract entities as much as possible. Hence he did not elect to introduce possible worlds and possibilia into his ontology. In addition, he held a reductionist view, which is called modal actualism by Fine or modalism by Melia. Prior was inspired by various authors (...) but this paper mainly discusses the influence of two prominent sources, Wittgenstein and logicians from Warsaw School. Prior acknowledged Wittgenstein’s influence, when he discuss the view that possible worlds consist of propositions. The second important feature of Prior’s concept is the denial of the real existence of possible worlds and the denial of the existence of entities which are in them. It was probably enabled by Prior’s adoption of some systems of logic invented by logicians from the Warsaw school, especially Lesniewski’s and Łukasiewicz’s systems. (shrink)