One of the most influential of the Victorian philosophers, Henry Sidgwick also made important contributions to fields such as economics, political theory, and classics. An active promoter of higher education for women, he founded Cambridge's Newnham College in 1871. He attended Rugby School and then Trinity College, Cambridge, where he remained his whole career. In 1859 he took up a lectureship in classics, and held this post for ten years. In 1869, he moved to a lectureship in moral philosophy, the (...) subject where he left arguably his greatest mark when he produced this work, regarded as his masterpiece. Published in 1874, the book argues the utilitarian approach to ethics, and a systematic and historically sensitive approach to ethical research that influenced utilitarian philosophers well into the twentieth century. It remains a valuable introduction to the philosophy, practice and history of ethics. This reissue includes the 1877 supplement. (shrink)

Recent experimental studies dispute the position that commonsense morality accepts ‘Ought’ Implies ‘Can’, the view that, necessarily, if an agent ought to perform some action, then she can perform that action. This paper considers and supports explanations for the results of these studies on the hypothesis that OIC is intuitive and true.

First published in 2000. Routledge is an imprint of Taylor & Francis, an informa company.

First published in 2000. Routledge is an imprint of Taylor & Francis, an informa company.

Part I Describing and Prescribing He to whom thou was sent for ease, being by name Legality, is the son of the Bond-woman . . . how canst thou expect by ...

I defend the following version of the ought-implies-can principle: (OIC) by virtue of conceptual necessity, an agent at a given time has an (objective, pro tanto) obligation to do only what the agent at that time has the ability and opportunity to do. In short, obligations correspond to ability plus opportunity. My argument has three premises: (1) obligations correspond to reasons for action; (2) reasons for action correspond to potential actions; (3) potential actions correspond to ability plus opportunity. In the (...) bulk of the paper I address six objections to OIC: three objections based on putative counterexamples, and three objections based on arguments to the effect that OIC conflicts with the is/ought thesis, the possibility of hard determinism, and the denial of the Principle of Alternate Possibilities. (shrink)

This paper tests a theory about the relationship between two important topics in moral philosophy and psychology. One topic is the function of normative language, specifically claims that one “ought” to do something. Do these claims function to describe moral responsibilities, encourage specific behavior, or both? The other topic is the relationship between saying that one “ought” to do something and one’s ability to do it. In what respect, if any, does what one “ought” to do exceed what one “can” (...) do? The theory tested here has two parts: (1) “ought” claims function to both describe responsibilities and encourage people to fulfill them (the dual-function hypothesis); (2) the two functions relate differently to ability, because the encouragement function is limited by the person’s ability, but the descriptive function is not (the interaction hypothesis). If this theory is correct, then in one respect “ought implies can” is false because people have responsibilities that exceed their abilities. But in another respect “ought implies can” is legitimate because it is not worthwhile to encourage people to do things that exceed their ability. Results from two behavioral experiments support the theory that “ought” exceeds but implies “can.” Results from a third experiment provide further evidence regarding an “ought” claim’s primary function and how contextual features can affect the interpretation of its functions. (shrink)

Ulrike Heuer argues that there can be a reason for a person to perform an action that this person cannot perform, as long as this person can take efficient steps towards performing this action. In this reply, I first argue that Heuer's examples fail to undermine my claim that there cannot be a reason for a person to perform an action if it is impossible that this person will perform this action. I then argue that, on a plausible interpretation of (...) what 'efficient steps' are, Heuer's claim is consistent with my claim. I end by showing that Heuer fails to undermine the arguments I gave for my claim. (shrink)

Many philosophers claim that it cannot be the case that a person ought to perform an action if this person cannot perform this action. However, most of these philosophers do not give arguments for the truth of this claim. In this paper, I argue that it is plausible to interpret this claim in such a way that it is entailed by the claim that there cannot be a reason for a person to perform an action if it is impossible that (...) this person will perform this action. I then give three arguments for the truth of the latter claim, which are also arguments for the truth of the former claim as I interpret it. (shrink)

Walter Sinnott-Armstrong argues that 'ought' does not entail 'can', but instead conversationally implicates it. I argue that Sinnott-Armstrong is actually committed to a hybrid view about the relation between 'ought' and 'can'. I then give a tensed formulation of the view that 'ought' entails 'can' that deals with Sinnott-Armstrong's argument and that is more unified than Sinnott-Armstrong's view.

A familiar complaint against the principle that “ought” implies “can” is that it seems that agents can intentionally make it the case that they cannot perform acts that they nonetheless ought to perform. I propose a related principle that I call the principle that “the thing to do” implies “can.” I argue that the principle that “the thing to do” implies “can” is implied by important but underappreciated truths about practical reason, and that it is not vulnerable to the familiar (...) complaint against “ought” implies “can.” Moreover, I suggest that “the thing to do” implies “can” has interesting implications for “ought” implies “can” - implications that depend on the relation between claims about what we ought to do and claims about the thing to do. (shrink)

In this paper, I argue that the “Ought Implies Can” (OIC) principle, as it is employed in epistemology, particularly in the literature on epistemic norms, is open to counterexamples. I present a counterexample to OIC and discuss several objections to it. If this counterexample works, then it shows that it is possible that S ought to believe that p, even though S cannot believe that p. If this is correct, then OIC, considered from an epistemic point of view, is false, (...) since it is supposed to hold for any S and any p. (shrink)

Experimental philosophers are often puzzled as to why many armchair philosophers question the philosophical significance of their research. Armchair philosophers, in contrast, are often puzzled as to why experimental philosophers think their work sheds any light on traditional philosophical problems. I argue there is truth on both sides.

This paper aims to contribute to the current debate about the status of the “Ought Implies Can” principle and the growing body of empirical evidence that undermines it. We report the results of an experimental study which show that people judge that agents ought to perform an action even when they also judge that those agents cannot do it and that such “ought” judgments exhibit an actor-observer effect. Because of this actor-observer effect on “ought” judgments and the Duhem-Quine thesis, talk (...) of an “empirical refutation” of OIC is empirically and methodologically unwarranted. What the empirical fact that people attribute moral obligations to unable agents shows is that OIC is not intuitive, not that OIC has been refuted. (shrink)

It is commonly assumed that ‘ought’ implies ‘can’, that is, that if we ought to do something, then it must be the case that we can do it. It is a frequent quip about this thesis that any account must specify three things: what is meant by the ‘ought’, what is meant by the ‘implies’, and what is meant by the ‘can’. Something is missed, though, when we state the thesis in its shortened, three-word form. We overlook what it means (...) to do something. It is, I think, not mere coincidence that nobody has discussed this issue: It is very difficult to specify what it means to do something in the relevant sense. This paper is devoted to fleshing out one way of doing something that is a problem for the thesis. (shrink)

In this paper, I argue that a person can have a reason to do what she cannot do. In a nutshell, the argument is that a person can have derivate reasons relating to an action that she has a non-derivative reason to perform. There are clear examples of derivative reasons that a person has in cases where she cannot do what she (non-derivatively) has reason to do. She couldn’t have those derivative reasons, unless she also had the non-derivative reason to (...) do what she cannot do. I discuss a number of objections to this view, in particular two: (1) The objection that if there were reasons to do what one cannot do, many of those would be ‘crazy reasons’, and (2) the worry that if there were such reasons, then agents would have reasons to engage in futile deliberations and tryings. I develop an explanation of ‘crazy reasons’ that shows that not all reasons to do the impossible are crazy and only those that are need to be filtered out, and, regarding the second objecting, I show that the reasons for trying as well as for taking the means to doing something—instrumental reasons in a broad sense—are different from the reasons for performing the action in the first place. They are affected by impossibility, and we can explain why that is so. The view I argue for is that a person may have a reason to do what she cannot do, but she does not have a reason to try to do so or to take means to realizing the impossible. (shrink)

Most philosophers assume that ‘ought’ implies ‘can’, and most of them hold that this principle is true not only universally but also analytically or conceptually. Some skeptics deny this principle, although they often admit some related one. In this article, we show how new empirical evidence bolsters the skeptics’ arguments. We then defend the skeptical view against some objections to the empirical evidence and to its effect on the traditional principle. In light of the new evidence, we conclude that philosophers (...) should stop unconditionally assuming that ‘ought’ implies ‘can’. (shrink)

According to the principle of alternate possibilities (PAP), a person is morally responsible for an action only if he could have done otherwise. PAP underlies a familiar argument for the incompatibility of moral responsibility with determinism. I argue that Harry Frankfurt's famous argument against PAP is unsuccessful if PAP is interpreted as a principle about blameworthiness. My argument turns on the maxim that "ought implies can" as well as a "finely-nuanced" view of the object of blame. To reject PAP on (...) the blameworthiness interpretation, we must reject either this maxim or the finely-nuanced view or some other apparently innocuous assumption. (shrink)

Recently, psychologists have explored moral concepts including obligation, blame, and ability. While little empirical work has studied the relationships among these concepts, philosophers have widely assumed such a relationship in the principle that “ought” implies “can,” which states that if someone ought to do something, then they must be able to do it. The cognitive underpinnings of these concepts are tested in the three experiments reported here. In Experiment 1, most participants judge that an agent ought to keep a promise (...) that he is unable to keep, but only when he is to blame for the inability. Experiment 2 shows that such “ought” judgments correlate with judgments of blame, rather than with judgments of the agent’s ability. Experiment 3 replicates these findings for moral “ought” judgments and finds that they do not hold for nonmoral “ought” judgments, such as what someone ought to do to fulfill their desires. These results together show that folk moral judgments do not conform to a widely assumed philosophical principle that “ought” implies “can.” Instead, judgments of blame play a modulatory role in some judgments of obligation. (shrink)

This paper contributes to the debate on whether we can have reason to do what we are unable to do. I take as my starting point two papers recently published in Philosophical Studies , by Bart Streumer and Ulrike Heuer, which defend the two dominant opposing positions on this issue. Briefly, whereas Streumer argues that we cannot have reason to do what we are unable to do, Heuer argues that we can have reason to do what we are unable to (...) do when we can get closer to success but cannot have reason to try to do what we are unable to do when we cannot get closer to success. In this paper, I reject both positions as they are presented, on the grounds that neither can accommodate an important category of reasons, which are the reasons to realise and to try to realise dimensions of value that lie at the boundary of what is realisable, specifically, genuinely valuable ideals. I defend a third view that we can have reason to do and to try to do what we are unable to do even when we cannot, in Heuer’s sense, get closer to success. Moreover, I argue that we can have reason to realise and to try to realise genuinely valuable ideals for their own sake and not simply for the sake of achieving mundane, realisable ends. (shrink)

Commonsense Consequentialism is a book about morality, rationality, and the interconnections between the two. In it, Douglas W. Portmore defends a version of consequentialism that both comports with our commonsense moral intuitions and shares with other consequentialist theories the same compelling teleological conception of practical reasons. Broadly construed, consequentialism is the view that an act's deontic status is determined by how its outcome ranks relative to those of the available alternatives on some evaluative ranking. Portmore argues that outcomes should be (...) ranked, not according to their impersonal value, but according to how much reason the relevant agent has to desire that each outcome obtains and that, when outcomes are ranked in this way, we arrive at a version of consequentialism that can better account for our commonsense moral intuitions than even many forms of deontology can. What's more, Portmore argues that we should accept this version of consequentialism, because we should accept both that an agent can be morally required to do only what she has most reason to do and that what she has most reason to do is to perform the act that would produce the outcome that she has most reason to want to obtain.Although the primary aim of the book is to defend a particular moral theory, Portmore defends this theory as part of a coherent whole concerning our commonsense views about the nature and substance of both morality and rationality. Thus, it will be of interest not only to those working on consequentialism and other areas of normative ethics, but also to those working in metaethics. Beyond offering an account of morality, Portmore offers accounts of practical reasons, practical rationality, and the objective/subjective obligation distinction. (shrink)

The principal aim of this book is to develop and defend an analysis of the concept of moral obligation. The analysis is neutral regarding competing substantive theories of obligation, whether consequentialist or deontological in character. What it seeks to do is generate solutions to a range of philosophical problems concerning obligation and its application. Amongst these problems are deontic paradoxes, the supersession of obligation, conditional obligation, prima facie obligation, actualism and possibilism, dilemmas, supererogation, and cooperation. By virtue of its normative (...) neutrality, the analysis provides a theoretical framework within which competing theories of obligation can be developed and assessed. This study is a major contribution to metaethics that will be of particular interest to all philosophers concerned with normative ethical theory. (shrink)

The capacity for representing and reasoning over sets of possibilities, or modal cognition, supports diverse kinds of high-level judgments: causal reasoning, moral judgment, language comprehension, and more. Prior research on modal cognition asks how humans explicitly and deliberatively reason about what is possible but has not investigated whether or how people have a default, implicit representation of which events are possible. We present three studies that characterize the role of implicit representations of possibility in cognition. Collectively, these studies differentiate explicit (...) reasoning about possibilities from default implicit representations, demonstrate that human adults often default to treating immoral and irrational events as impossible, and provide a case study of high-level cognitive judgments relying on default implicit representations of possibility rather than explicit deliberation. (shrink)

According to the Ought-Implies-Can principle (OIC), an agent ought to perform a certain action only if the agent can perform that action. Proponents of OIC interpret this supposed implication in several ways. Some argue that the implication in question is a logical one, namely, entailment. Some think that the relation between ‘ought’ and ‘can’ is a relation of presupposition. Still others argue that ‘ought’ conversationally implicates ‘can’. Opponents of OIC offer a variety of counterexamples in an attempt to show that (...) there are cases in which an agent ought to perform a certain action even though she cannot perform that action. Such counterexamples often involve either culpable or nonculpable inability. In cases of culpable inability, the agent renders herself unable to fulfill an obligation. For example, a student is unable to submit a paper on the due date because she procrastinated until it became too late to write a paper by the assigned deadline. In cases of non-culpable inability, the agent somehow becomes unable to fulfill an obligation, through no fault of her own. For example, an agent becomes unable to pay back a loan to a bank because she was robbed on her way to the bank. This paper attempts to offer counterexamples to OIC of a sort different from the one discussed by opponents of OIC so far. If these counterexamples are correct, then they seem to suggest that there are cases in which an agent has an obligation to perform an action even though she may not be able to perform that action, and thus OIC is false. In other words, ‘ought’ does not imply ‘can’. (shrink)

Most philosophers believe that a person can have an obligation only insofar as she is able to fulfil it, a principle generally referred to as “Ought Implies Can”. Arguably, this principle reflects something basic about the ordinary concept of obligation. However, in a paper published recently in this journal, Wesley Buckwalter and John Turri presented evidence for the conclusion that ordinary people in fact reject that principle. With a series of studies, they claimed to have demonstrated that, in people’s judgements, (...) obligations persist irrespective of whether those who hold them have the ability to fulfil them. We argue in this paper that due to some problems in their design, Buckwalter & Turri’s conclusions may not be war- ranted. We present the results of a series of studies demonstrating the problems with their design and showing that, with an improved design, people judge that obligation depends on ability after all. (shrink)

It is often thought that judgments about what we ought to do are limited by judgments about what we can do, or that “ought implies can.” We conducted eight experiments to test the link between a range of moral requirements and abilities in ordinary moral evaluations. Moral obligations were repeatedly attributed in tandem with inability, regardless of the type (Experiments 1–3), temporal duration (Experiment 5), or scope (Experiment 6) of inability. This pattern was consistently observed using a variety of moral (...) vocabulary to probe moral judgments and was insensitive to different levels of seriousness for the consequences of inaction (Experiment 4). Judgments about moral obligation were no different for individuals who can or cannot perform physical actions, and these judgments differed from evaluations of a non-moral obligation (Experiment 7). Together these results demonstrate that commonsense morality rejects the “ought implies can” principle for moral requirements, and that judgments about moral obligation are made independently of considerations about ability. By contrast, judgments of blame were highly sensitive to considerations about ability (Experiment 8), which suggests that commonsense morality might accept a “blame implies can” principle. (shrink)

In this paper, I present the results of an experimental study on intuitions about moral obligation (ought) and ability (can). Many philosophers accept as an axiom the principle known as “Ought Implies Can” (OIC). If the truth of OIC is intuitive, such that it is accepted by many philosophers as an axiom, then we would expect people to judge that agents who are unable to perform an action are not morally obligated to perform that action. The results of my experimental (...) study show that participants were more inclined to judge that an agent ought to perform an action than that the agent can perform the action. Overall, participants said that an agent ought to perform an action even when they said that the agent cannot do it. I discuss the implications of these results for the debate over OIC. (shrink)

I report the results of a follow-up study, designed to address concerns raised by Kurthy and Lawford-Smith in response to my original study on intuitions about moral obligation (ought) and ability (can). Like the results of the original study, the results of the follow-up study do not support the hypothesis that OIC is intuitive. The results of both studies suggest that OIC is probably not a principle of ordinary moral cognition. As I have argued in my paper, I take this (...) to mean that OIC can no longer be taken as axiomatic. It must be argued for without appealing to intuitions. (shrink)