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)

Hume's Law states that a valid argument cannot have an ethical conclusion and non-ethical premises. Prior proposes the following counterexample: `Tea-drinking is common in England; therefore, either tea-drinking is common in England or all New Zealanders ought to be shot.' One strategy for responding to Prior is to restrict Hume's Law to arguments that contain no `mixed sentences', i.e., sentences like the disjunctive conclusion in Prior's example. Here I examine this strategy in the context of first-order logic. I consider five (...) interpretations of Hume’s Law, three of which I show to be true. (shrink)

The 'No Ought From Is' principle faces a dilemma. If 'mixed' sentences, i.e. those containing both ethical and non-ethical predicates, are included as 'oughts', then the principle is false. But if mixed sentences are excluded, then the principle is irrelevant to ethics, because ethical arguments typically involve mixed sentences. This paper proposes a solution to the dilemma: a sentence is to be counted as an 'ought' just in case it has ethical ontological commitments. This interpretation of No Ought From Is (...) is shown to be both true and relevant. (shrink)

Environmental ethics in its modem classical expression by Aldo Leopold appears to fall afoul of Hume’s prohibition against deriving ought-statements from is-statements since it is presented as a logical consequence of the science of ecology. Hume’s is/ought dichotomy is reviewed in its historical theoretical context. A general formulation bridging is and ought, in Hume’s terms, meeting his own criteria for sound practical argument, is found. It is then shown that Aldo Leopold’s land ethic is expressible as a special case of (...) this general formulation. Hence Leopold’s land ethic, despite its direct passage from descriptive scientific premises to prescriptive normative conclusions, is not in violation of any logical strictures which Hume would impose upon axiological reasoning. (shrink)

Part I of this essay described "Ought" and "Value" as forms of moral requiredness. Now in Part II, a description of the ideal conditions for veridical perceptions of moral requiredness are specified. This is done in the form of an ideal observer type of analysis. This analysis is defended against those who oppose naturalism by assuming a bifurcation between 'ought' and 'is' and those who accuse naturalism of a "naturalistic fallacy." It is argued that theistic versions of the ideal observer (...) form of analysis exist in the Christian tradition in logically acceptable and plausible formulations. Specific illustrations are provided. (shrink)

This is the first of two essays concerned to specify in what sense "ought" and "value" are genuine characteristics of reality serving as data that help us empirically verify the truth and falsity of our moral judgments. This, the first, essay discusses the significance of the ought/is question for moral philosophy and theological ethics, giving reasons for the inadequacy of current views on the relation between "ought" and "is." Building on the perceptual theories of Gestalt psychologists yields a phenomenological description (...) of the nature of "ought" and "value" as unique experiences of gap-induced demands or requiredness. These moral experiences of requiredness are delineated in such a way that they are distinguishable from aesthetic, logical, and causal forms of requiredness. (shrink)

Various formally valid counterexamples have been adduced against the Humean dictum that one cannot derive an “ought” from an “is.” There are formal rebuttals—some very sophisticated now (e.g., Charles R. Pigden’s and Gerhard Schurz’s)—to such counterexamples. But what follows is an intuitive and informal argument against them. I maintain that it is better than these sophisticated formal defenses of the Humean dictum and that it also helps us see why it implausible to think that we can be as decisive about (...) the truth or falsity of the dictum as both the formal counterexamples or formal barriers to them purport to be. (shrink)

Hume seems to claim that there does not exist a valid argument that has all non-ethical sentences as premises and an ethical sentence as its conclusion. Starting with Prior, a number of counterexamples to this claim have been proposed. Unfortunately, all of these proposals are controversial. Even the most plausible have a premise that seems like it might be an ethical sentence or a conclusion that seems like it might be non-ethical. Since it is difficult to tell whether any of (...) these counterexamples are genuine, we need a taxonomy that sorts out ethical sentences from non-ethical ones. We need to know the difference between an ‘Is’ and an ‘Ought’. In the first part of the paper, I establish the need for a taxonomy. I consider some of the most influential ‘Is’–‘Ought’ derivations. These include proposals by Prior and Searle. I argue that each proposal has a premise whose status as ethical or non-ethical is difficult to determine. In the second part of the paper, I consider taxonomies proposed by Karmo and Maitzen. I argue against both taxonomies. I end with the claim that we need a taxonomy of ethical sentences and that none of the current proposals are adequate. (shrink)

The debate concerning the proper way of understanding, and hence solving, the “is-ought problem” produced two mutually exclusive positions. One position claims that it is entirely impossible to deduce an imperative statement from a set of factual statements. The other position holds a contrary view to the effect that one can naturally derive an imperative statement from a set of factual statements under certain conditions. Although these two positions have opposing views concerning the problem, it should be evident that they (...) both accept that the “is-ought problem” is concerned with the deducibility of imperative statements from factual statements. Later I will argue that this should not be our concern when we try to make sense of the way we reason about morality. (shrink)

If the logic of belief changes is extended to cover belief states which contain both factual and normative beliefs, it is easily shown that a change of a factual belief (an 'Is') in a mixed belief state can imply a change of a normative belief (an 'Ought') in the same state. With regard to Hume's so-called 'Is-Ought problem', this means that one has to distinguish its statics from its dynamics. When this is done, it becomes clear that changes of factual (...) beliefs can, for rational reasons, have far-reaching normative consequences. Similarly, a change of a factual belief can imply a change of a value belief. (shrink)

Many naturalistically-minded philosophers want to accomplish a naturalistic reduction of normative (e.g. moral and epistemic) claims. Mindful of avoiding the naturalistic fallacy, such philosophers claim that they are not reducing moral and epistemic concepts or definitions. Rather, they are only reducing the extension of these normative terms, while admitting that the concepts possess a normative content that cannot be naturalistically reduced. But these philosophers run into a serious problem. I will argue that normative claims possess two dimensions of normativity. I (...) will further argue that certain of the reductionist’s commitments require that these two dimensions of normativity be given a naturalistic reduction, while the other of the reductionist’s commitments make such a reduction impossible. Thus, the reductionist’s commitments both require and forbid a reductionist account of morality and epistemology. Thus, as we will see, reductionism is torn between two incompatible requirements, and must fail. (shrink)

In the current issue of this journal, Scott Hill critiques some of my work on the “is”-“ought” controversy, the Hume-inspired debate over whether an ethical conclusion can be soundly, or even validly, derived from only non-ethical premises. I’ve argued that it can be; Hill is unconvinced. I reply to Hill’s critique, focusing on four key questions to which he and I give different answers.

According to global skepticism, we know nothing. According to local skepticism, we know nothing in some particular area or domain of discourse. Unlike their global counterparts, local skeptics think they can contain our invincible ignorance within limited bounds. I argue that they are mistaken. Local skepticism, particularly the kinds that most often get defended, cannot stay local: if there are domains whose truths we cannot know, then there must be claims outside those domains that we cannot know even if they (...) are true. My argument focuses on one popular form of local skepticism, ethical skepticism, but I believe that the argument generalizes to cover other forms as well. (shrink)

Some philosophers have been attracted to the idea that morality is an autonomous domain. One version of this idea is the thesis that non-moral claims are irrelevant to the justification of fundamental normative ethical theories. However, this autonomy thesis appears to be in tension with a pair of apparent features of metaethical theorizing. On one hand, metaethics seemingly aims to explain how morality fits into our broader conception of the world. On the other, metaethical theorizing appears to have potential normative (...) ethical implications. This apparent tension may help to explain some contemporary worries about metaethics as a philosophical project. This paper examines three responses to this tension. The first response seeks to resolve the tension by claiming that metaethical theories must be neutral between normative ethical theories. The second response seeks to eliminate the tension by appealing to a deep divide between practical and theoretical reasoning. I show that each of these responses would require a radical reconception of metaethics. I argue that such a reconception is not required in order to resolve the apparent tension between metaethics and the autonomy thesis. I show that this tension is merely apparent, and can be dissolved without casting doubt on metaethics as a project. I argue that on the picture that results, whether the autonomy thesis is true itself depends upon metaethical fact. (shrink)

Are there good arguments from Is to Ought? Toomas Karmo has claimed that there are trivially valid arguments from Is to Ought, but no sound ones. I call into question some key elements of Karmo’s argument for the “logical autonomy of ethics”, and show that attempts to use it as part of an overall case for moral skepticism would be self-defeating.

Why have so many philosophers agonised over the possibility of valid arguments from factual premises to moral conclusions? I suggest that they have done so, because of worries over a sceptical argument that has as one of its premises, `All moral knowledge must be non-inferential, or, if inferential, based on valid arguments or strong inductive arguments from factual premises'. I argue that this premise is false.

Book Information The Is-Ought Problem: An Investigation in Philosophical Logic. By Gerhard Schurz. Kluwer. Dordrecht. 1997. Pp. x + 332. £92.25.

Frank Snare had a puzzle. He construed Hume as a non-cognitivist, indeed, as the non-cognitivist, the fount and origin of contemporary non-cognitivism. Taking Hume to be a non-cognitivist, Snare devoted a great deal of time and effort to the Motivation Argument, or as he called it, the Influence Argument, which he took to be the chief weapon in Hume.

There have been books written since 1997 both on Hume’s ethics and on metaethics generally which make no mention of Gerhard Schurz’s The Is-Ought Problem. I don’t say that they are ipso facto bad books since they may have merits which make up for this glaring defect. But Schurz’s magnificent The Is-Ought Problem is a major contribution to both logic and metaethics and ethicists who disregard it do so at their intellectual peril.

In every system of morality I have hitherto met with, I have always remark'd that the author proceeds for some time in the ordinary way of reasoning, and establishes the being of a God or makes observations concerning human affairs; when of a sudden I am surpriz'd to find, that instead of the usual copulations of propositions is and is not, I meet with no proposition that is not connected with an ought or ought not. This change is imperceptible, but (...) is, however, of the last consequence. For as this ought or ought not expresses some new relation or affirmation, 'tis necessary that it should be observ'd and explain'd; and at the same time a reason should be given for what seems altogether inconceivable, how this new relation can be a deduction from others which are entirely different from it. (shrink)

Implication barrier theses deny that one can derive sentences of one type from sentences of another. Hume’s Law is an implication barrier thesis; it denies that one can derive an ‘ought’ (a normative sentence) from an ‘is’ (a descriptive sentence). Though Hume’s Law is controversial, some barrier theses are philosophical platitudes; in his Lectures on Logical Atomism, Bertrand Russell claims: You can never arrive at a general proposition by inference particular propositions alone. You will always have to have at least (...) one general proposition in your premises. (Russell, 1918, p. 206) We will refer to this claim—that one cannot derive general sentences from particular sentences—as Russell’s Law.1 A third barrier thesis claims that one cannot derive sentences about the future from sentences about the past or present. Hume’s endorsement of this barrier thesis is well-known: all inferences from experience suppose, as their foundation, that the future will resemble the past . . . if there be any suspicion that the course of nature may change, and that the past may be no rule for the future, all experience becomes useless, and can give rise to no inference or conclusion. It is impossible, therefore, that any argument from experience can prove this resemblance of the past to the future; since all these arguments are founded on the supposition of that resemblance. (Hume, EHU 4.21/37) We will refer to this barrier thesis as Hume’s Second Law. A fourth barrier thesis says that one cannot derive a necessary sentence from one about the actual world and we will refer to this last thesis Kant’s Law. Such implication barrier theses present a problem. (shrink)

An argument defending the view that one cannot derive an ought from an is against the usual (suspect) counterexamples.

The formulation and proof of Hume’s Law and several related inference barrier theses.

"THE central problem in moral philosophy is commonly known as the is-ought problem." So runs the opening sentence of the introduction to a recent volume of readings on this issue. [1] Taken as a statement about the preoccupations of moral philosophers of the present century, we can accept this assertion. The problem of how statements of fact are related to moral judgments has dominated recent moral philosophy. Associated with this problem is another, which has also been given considerable attention - (...) the question of how morality is to be defined. The two issues are linked, since some definitions of morality allow us to move from statements of fact to moral judgments, while others do not. In this article I shall take the two issues together, and try to show that they do not merit the amount of attention they have been given. I shall argue that the differences between the contending parties are terminological, and that there are various possible terminologies, none of which has, on balance, any great advantage over any other terminology. So instead of continuing to regard these issues as central, moral philosophers could, I believe, "agree to disagree" about the "is-ought" problem, and about the definition of morality, provided only that everyone was careful to stipulate how he was using the term "moral" and was aware of the implications and limitations of the definition he was using. Moral philosophers could then move on to consider more important issues. (shrink)

Many philosophers claim that no formally valid argument can have purely non-normative premises and a normative or moral conclusion that occurs essentially. Mark Nelson recently proposed a new counterexample to this Humean doctrine.

In his paper, How to Derive ‘Ought’ From ‘Is,’ John R. Searle made a valiant attempt to derive an ought-statement from purely descriptive statements. In a recent issue of Philosophia, Scott Hill has offered criticisms of that proposed derivation. I argue that Hill has not established any errors in Searle's proposed derivation.