Ought-implies-can: Erasmus Luther and R.M. Hare

Ethics, 2009

Analysis, 2016

premisses that (i) 'T' refers (only) to T and (ii) T contains 'is true' and hence states an alethic fact. That is sufficient information to build the dependency graph and conclude that T does not depend on any non-alethic fact and hence is ungrounded. Exactly the same goes for L and C, with the usual paradoxical consequences. Given that (i) 'L' refers (only) to L and (ii) L contains 'is true' and hence states an alethic fact, we can build L's dependency graph and determine, A-decidably, that it contains only alethic nodes. So, A-decidably, L is not grounded by any non-alethic fact and hence, by (TM), is not true. It is A-decidable that L is not true. (Exactly the same reasoning applies to C.) Then L is assertible and apt for inclusion in standard logical reasoning. But that reasoning quickly leads to absurdity: we can assert the Liar equivalence (L is true iff it is not true), from which it follows that L is both true and not true. The paradox has not been blocked. 5. Conclusion I've argued that we can, in certain cases, draw clear, A-decidable conclusions about a sentence's alethic dependencies. From clear facts about a sentence's syntax and reference of its terms, we can build dependency graphs (Section 3) and reason about a sentence's dependencies. In particular, we can determine, A-decidably, that L is ungrounded, hence not true; but this quickly results in absurdity. So, A-decidably, we must reject Barker's proposal.

Since it was presented in 1963, Chisholm’s paradox has attracted constant attention in the deontic logic literature, but without the emergence of any definitive solution. We claim this is due to its having no single solution. The paradox actually presents many challenges to the formalization of deontic statements, including (1) context sensitivity of unconditional oughts, (2) formalizing conditional oughts, and (3) distinguishing generic from nongeneric oughts. Using the practical interpretation of ‘ought’ as a guideline, we propose a linguistically motivated logical solution to each of these problems, and explain the relation of the solution to the problem of contrary-to-duty obligations.

The Journal of Value Inquiry, 1980

Unless Z stops voting with the opposition, he will not retain his seat in the council. (3) Therefore, Z ought to stop voting with the opposition. 1" This is an instantiation of an inference scheme, which belongs to a family of similar schemes, explored (among'others) by G. H. yon Wright under the denomination of "practical inference. ''2 The premises are both straightforward assertions of fact. (1) concerns a matter of psychological fact. (2) is an "anankastic ''3 statement about the means indispensable to some end. They do not (unless accidentally) contain any "action-guiding" or, in R. M. Hate's terminology, "prescriptive" or "imperative" element. But (3) does, and more than accidentally. Or at least this is part of the doctrine know as "prescriptivism." The inference therefore seems to be in violation of Poincar6's rule: "No imperative conclusion can be validly drawn from a set of premises which does not contain at least one imperative. ''4 This logical rule Hare takes to be the basis of Hume's observation on the impossibility of deducing an "ought" from an "is." Practical inferences, not surprisingly, have often been employed as counterexamples to Hume's thesis. 5 One of the best-known attempts is an article by M. Black. 6 Black considers the objection, "that any argument of the above form is really an enthymeme with an unstated premise, possibly of the form: everybody should do anything which is the one and only way to achieve anything that he wants to achieve. ''7 His answer is that the proposed additional premise must be held to be analytic. Hare, in his turn, considers this "apparently analytic step" and finds it "one of Satan's cleverest sophisms, and many there be who have gone to hell through being beguiled by it."8 No wonder: not only Hume's thesis is at stake, but prescriptivism too. In confirmation of Poincar6's Rule, Hare inter alia appeals to the general logical consideration "that there must be nothing said in the conclusion which

Every adequate semantics for conditionals and deontic "ought" must offer a solution to the miners paradox about conditional obligations. Kolodny and MacFarlane have recently argued that such a semantics must reject the validity of modus ponens. I demonstrate that rejecting the validity of modus ponens is inessential for an adequate solution to the paradox

I motivate and characterize an intensional semantics for ‘ought’ on which it does not behave as a universal quantifier over possibilities. My motivational argument centers on taking at face value some standard challenges to the quantificational semantics, especially to the idea that ‘ought’-sentences satisfy the principle of Inheritance. I argue that standard pragmatic approaches to these puzzles are either not sufficiently detailed or unconvincing.

2021

Haji argues that determinism threatens deontic morality, not via a threat to moral responsibility, but directly, because of the principle that “ought” implies “can”. Haji’s argument requires not only that we embrace an “ought” implies “can” principle, but also that we adopt the principle that “ought” implies “able not to”. I argue that we have little reason to adopt the latter principle, and examine whether deontic morality might be destroyed on the basis of the more commonly embraced “ought” implies “can” principle alone. I argue that despite what look like initially compelling reasons why we might suppose that this weaker conclusion is similarly destructive to deontic morality, we actually have good reason to doubt that it has any practical relevance for moral deliberation at all.

Pigden, Charles R ed. Hume on ‘Is’ and ‘Ought’, Houndmills, Palgrave, 169-191,Macmillan, , 2010

Frank Snare had a puzzle. Noncognitivism implies No-Ought-From-Is but No- Ought-From-Is does not imply non-cognitivism. How then can we derive non-cognitivism from No-Ought-From-Is? Via an abductive argument. If we combine non-cognitivism with the conservativeness of logic (the idea that in a valid argument the conclusion is contained in the premises), this implies No-Ought-From-Is. Hence if No-Ought-From-Is is true, we can arrive at non-cognitivism via an inference to the best explanation. With prescriptivism we can make this argument more precise. I develop an account of imperative consequence that underwrites Hare’s principle that you cannot derive imperatives from indicatives. Thus if moral judgments contain an imperative component, it will be impossible to derive moral conclusions from indicative or non-moral premises. Given this account of imperative consequence, we can explain No-Ought-From-Is without appealing to anything as nebulous as the conservativeness of logic. Hence if No-Ought-From-Is is true, we have an inference to the best explanation for prescriptivism. Both lines of argument face problems from Prior. Given Prior’s counterexamples, No-Ought-From-Is as originally conceived is false. The version that survives is No-Non-Vacuous-Ought-From-Is. But the best explanation of this does not include non-cognitivism. With prescriptivism it is worse. For the version of No-Ought-From-Is that prescriptivism ‘explains’ – that is, the version of No-Ought-From-Is that prescriptivism implies – would exclude Prior’s counter-examples to Autonomy as invalid. But they are not invalid. Thus Prior’s counter-examples to No-Ought-From- Is refute prescriptivism. Thus from 1960 onwards R. M.Hare was a dead philosopher walking. But if non-cognitivism cannot be derived from No-Ought-From-Is, this suggests that it is not what Hume was trying to prove. I argue that what Hume was trying to prove is that moral truths are not demonstrable. To be demonstrable, a proposition must be either self-evident or logically derivable from self-evident propositions. By Treatise 3.1.1.27, Hume had proved to his own satisfaction that no moral propositions are self-evident. That leaves open the possibility that they are logically derivable from self-evident but NON-moral propositions. The point of No-Ought-From-Is was to exclude this possibility. If you cannot logically derive moral conclusions from non-moral premises, you cannot demonstrate the truths of morality by deriving them from self-evident but NON-moral truths. I also discuss why Hume abandoned No-Ought-From-Is in the EPM. He had no need of it since he thought he had a proof that (with some exceptions) no nontrivial truths are demonstrable. Hence no non-trivial MORAL truths are demonstrable. No-Ought-From-Is drops out as unnecessary.

Studia Philosophiae Christianae, 2018

Bernard Williams in his essay Ought and moral obligation (OMO) takes a stand on the proper logical interpretation of ‘ought’ sentences. He claims that ought being central to ethical reflection, that is, ought issuing personal requirements to agents, is to be interpreted like any ordinary ‘ought’ – as a propositional operator that is not indexed to a person. The driving idea behind Williams’s logical point about ‘ought’ seems to be that logical interpretation of ‘ought’ sentences with moral content in terms of indexed ought lacks semantic significance. John Broome disagrees. In a series of his recent writings devoted to an analysis of the notion of normative ought, he defends the view opposite to the one fostered by Williams. According to Broome, indexation of ‘ought’ to agent matters for extra-logical reasons; it is a way of exhibiting that ought has its normative owner, which in turn is important for determining the holder of responsibility for the ought in question. In the paper I argue that Broome may be right, but his arguments do not show that fact. In particular, I claim that he is wrong in thinking that indexation in terms of ownership is useful in the analysis of ‘ought’ sentences with agentive content, and thus nicely applies to moral ought being a paradigmatic example of such sentences. According to my diagnosis, Broome’s positive view about the semantic and ethical significance of interpreting agentive ought as indexed ought, suffers from one central problem. It alludes to an unsuccessful substantive semantics of ‘indexed ought’ that fails to give an accurate explanation of the meaning of the ought in question. I conclude the paper by offering an alternative to Broome’s substantive semantics of ‘indexed ought’, and explain why I think that it fares better in capturing the nature of the agentive ought.

Philosophia, 1989

The purpose of this paper is to discuss whether moral requirements range over actions or attempts. In particular, I shall examine two contexts in ethics theory that some have thought provide a basis for believing that attempts are what are morally required of agents. In both of these contexts there is an implicit appeal to the principle that 'ought' implies 'can'. In order to set the stage for my discussion of the central question, therefore, I need to begin by explaining how I think appeals to the principle that 'ought' implies 'can' typically work. Article: Part 1 If an agent is charged with wrongdoing, there are several ways that he might defend himself. He might, for example, admit that he has done something wrong, but contend that he should not be blamed for doing so. An agent who makes this defense is said to be offering an excuse for his behaviour. That one acted under duress is an example of an excuse. If I am rude to you after having been up all night tending to my sick mother. I will admit that I have behaved improperly but claim that because of the circumstances, I ought not to be blamed.

Knows-knows principles in epistemology (KK principles for short) say that if you know some proposition, then you are in a position to know that you know it. This paper examines the viability of analogous principles in ethics, which I call ought-ought principles (OO principles for short). Several epistemologists have recently offered new defenses of KK principles and of other related principles and there has recently been an increased interest in examining analogies between ethics and epistemology and so it seem natural to examine whether defenses of KK and related principles carry over to OO principles. In this paper I introduce two OO principles and I show how some arguments in favor of KK carry over to them. Then I show how these OO principles can be used to shed light on a much-discussed case in ethics, that of Professor Procrastinate.

Synthese, 2022

A thorny question surrounding the meaning of ought concerns a felt distinction between deontic uses of ought that seem to evaluate a state of affairs versus those that seem to describe a requirement or obligation to perform an action, as in (A) and (B), respectively. (A) There ought not be childhood death and disease. (B) You ought to keep that promise. Various accounts have been offered to explain the contrast between "agentive" and "non-agentive" ought sentences. One such account is the Agency-in-the-Prejacent theory ("AIP"), which traces the difference to a particular kind of ambiguity in the prejacent. This theory has been criticized as linguistically unviable. Indeed, I level a few novel complaints against AIP myself in the present paper. But AIP has a kernel of genuine insight which allows us to explain the contrast-that the distinction between agentive and non-agentive ought sentences owes in part to the way natural language encodes information about agency. I develop this idea into a novel account that, like AIP, traces the contrast to an ambiguity in the complement of the modal. However, according to the view I propose, the Coercion View, a linguistically-motivated coercion operation produces the necessary grammatical conditions for agentive ought, which in turn allow a kind of variadic function operator in the style of (in: Recanati, Literal Meaning. Cambridge University Press, 2004) to produce the semantic effect we see on display in agentive readings of ought. Having explained the mechanism by which we get this structure, I show that it corroborates some of the central intuitions underwriting agentive ought. I submit that the Coercion View offers an explanation of agentive ought to take at least as seriously as any of its competitors.

Oxford Handbook of Reasons and Normativity, 2018

Here we focus on two questions: What is the proper semantics for deontic modal expressions in English? And what is the connection between true deontic modal statements and normative reasons? Our contribution towards thinking about the first, which makes up the bulk of our paper, considers a representative sample of recent challenges to a Kratzer-style formal semantics for modal expressions, as well as the rival views—Fabrizio Cariani’s contrastivism, John MacFarlane’s relativism, and Mark Schroeder’s ambiguity theory—those challenges are thought to motivate. These include the Professor Procrastinate challenge to Inheritance (the principle that ‘If ought  and  entails , then ought ), as well as Parfit’s miners puzzle regarding information-sensitive deontic modals. Here we argue that a Kratzer-style view is able to meet all of the challenges we’ll consider. In addition, we’ll identify challenges for each of those rival views. Our overall conclusion is that a Kratzer-style semantics remains the one to beat. With this assumption in place, we then ask how we should understand the relationship between true deontic modal statements and normative reasons. Should, for example, we hold that the truth of such a statement entails the existence of a normative reason for some agent to comply? Here we argue that, in many cases, acceptance of Kratzer’s semantics for deontic modals leaves open for substantive normative theorizing the question of whether an agent has a normative reason to comply with what she ought to do.

Dialectica, 2021

Haji argues that determinism threatens deontic morality, not via a threat to moral responsibility, but directly, because of the principle that “ought” implies “can”. Haji’s argument requires not only that we embrace an “ought” implies “can” principle, but also that we adopt the principle that “ought” implies “able not to”. I argue that we have little reason to adopt the latter principle, and examine whether deontic morality might be destroyed on the basis of the more commonly embraced “ought” implies “can” principle alone. I argue that despite what look like initially compelling reasons why we might suppose that this weaker conclusion is similarly destructive to deontic morality, we actually have good reason to doubt that it has any practical relevance for moral deliberation at all.

2009

Page 1. 1 'Ought', 'Can', and Practical Reasons1 Clayton Littlejohn Many accept the principle that states that 'ought' implies 'can': OIC: S ought to Φ only if S can Φ.2 As intuitive as OIC might seem, we should acknowledge that the arguments offered in its support often do not warrant the sort of confidence many of us have in the principle.