Hume: The Is/Ought Gap

Hume’s Law that one cannot derive an “ought” from an “is” has often been deemed to bear a significance that extends far beyond logic. Repeatedly, it has been invoked as posing a serious threat to views about normativity: naturalism in metaethics and positivism in jurisprudence. Yet in recent years, a puzzling asymmetry has emerged: while the view that Hume’s Law threatens naturalism has largely been abandoned (due mostly to Pigden’s work, see e.g. Pigden 1989), the thought that Hume’s Law is (...) a serious challenge to positivism has only grown in prominence. Our main aim is to establish that Hume’s Law is not a threat to positivism or naturalism. First, we connect extensive, but unfortunately siloed, discussions of this issue. Second, we show that Hume’s Law is not a serious threat to naturalism or positivism, for the gap between logic and such theses is very hard to bridge in a way that would make Hume’s Law able to bear this significance. Finally, we emphasize an implication of our discussion: it undermines one of the main “dialectical tributaries” in jurisprudence (Toh 2018). (shrink)

In this paper, I argue for an interpretation of Hume's Law that sees him as dismissing all possible arguments from is to ought on the basis of a comparison with his famous argument on induction.

Moral conclusions cannot validly be inferred from nonmoral premises – this principle, commonly called “Hume’s law,” presents a conundrum. On one hand, it seems obviously true, and its truth is often simply taken for granted. On the other hand, an ingenious argument by A. N. Prior seems to refute it. My aim here is a resolution. I shall argue, first, that Hume’s law is ambiguous, admitting both a strong and a weak interpretation; second, that the strong interpretation is false, as (...) shown by Prior’s argument; and, third, that the weak interpretation is true. (shrink)

The appealing principle that you can't get an ‘ought’ from an ‘is’, sometimes called Hume's Guillotine , faces a well-known challenge: it must give a clear account of the distinction between normative and descriptive sentences while dodging counter-examples. I argue in this paper that recent efforts to answer this challenge fail because the distinction between normative and descriptive sentences cannot be described well enough to be of any help. As a result, no version of the principle is both true and (...) adequate. Yet a different principle—that no normative terms are synonymous with any descriptive terms—can satisfy much of the motivation we had for defending Hume's Guillotine in the first place. I show briefly how this second principle can explain why is-ought arguments are invalid, block some attempted deductive justifications of beliefs with normative terms, and create an explanatory advantage for moral non-cognitivism. Just so, giving up Hume's Guillotine is the prudent thi.. (shrink)

Within a single paragraph in his Treatise of Human Nature, David Hume prompted what has become one of the most central orthodoxies in ethical theory: the thesis that one cannot derive what ought to be from what there is. In the aftermath of Hume’s seminal discussion, the No-Ought-From-Is-thesis has obtained approval among moral theorists to the point that it has been assigned the status of an undisputed ‘law’. As common with commonplaces in philosophy, alas, both the exact content and argument (...) of ‘Hume’s Law’ have proven to be quite elusive. The present anthology aims to clarify and discuss several controversies surrounding the No-Ought-From-Is-thesis. (shrink)

Quais sáo as teorias vulgares da moralidade criticadas por Hume na famosa passagem is-ought ? Quais eram seus defensores? Neste ensaio, trato de algumas diferenças entre Hume e Hutcheson que podem iluminar algumas respostas. Hume, ao contrário de Hutcheson, combateu toda forma de separaçáo da natureza humana em componentes naturais e divinos. O conceito de simpatia cumpre uma funçáo essencial nesse aspecto. Há bons indícios de que o jovem Hume adotou no Tratado uma estratégia abertamente crítica a todas as teorias (...) morais defendidas pelos pensadores, religiosos e moralistas de sua época. Isso inclui o voluntarismo contratualista, as éticas racionalistas, bem como as concepções religiosas influenciadas pelo dogmatismo evangélico escocês. Nisso Hume distanciou-se de Hutcheson, pois sua crítica também incluía as visões influenciadas pelas teorias do direito natural com referência na providência divina. A passagem is-ought sinaliza essa intençáo. Todavia, todo esse ímpeto juvenil resultou numa série de maus resultados pessoais, o que o levou, na maturidade a mitigar sua agressividade filosófica e a adotar, em seus escritos, uma atitude mais equilibrada. (shrink)

Examining the moral sense theories of Francis Hutcheson, David Hume, and Adam Smith from the perspective of the is-ought problem, this essay shows that the moral sense or moral sentiments in those theories alone cannot identify appropriate morals. According to one interpretation, Hume's or Smith's theory is just a description of human nature. In this case, it does not answer the question of how we ought to live. According to another interpretation, it has some normative implications. In this case, it (...) draws normative claims from human nature. Anyway, the sentiments of anger, resentment, vengeance, superiority, sympathy, and benevolence show that drawing norms from human nature is sometimes morally problematic. The changeability of the moral sense and moral sentiments in Hume's and Smith's theories supports this idea. Hutcheson's theory is morally more appropriate because it bases morality on disinterested benevolence. Yet disinterested benevolence is not enough for morality. There are no sentiments the presence of which alone makes any action moral. (shrink)

The article compares David Humes’ and John Searle’s positions concerning the relation between descriptive and evaluative statements. Although the two positions seem to be just opposite in that Hume denies the derivability of the ought from the is, while Seale accepts it, the author shows that Hume and Searle have many similarities, for for both obligations rely upon the institution of promising. The difference is that for Hume the speech act of promising as such does not have intrinsic evaluative impact. (...) Only in the civil state can the calm passions emerge which give to the motivation to act its ought-character. For Searle, on the contrary, the evaluative character is intrinsically linked to the speech act of promising, so that it becomes possible to derive the ought from the is. At the end the question of the relation between institutional and moral institutions is addressed. (shrink)

This is a commentary on Adrian Heathcote’s interesting paper ‘Hume’s Master Argument’. Heathcote contends that No-Ought-From-Is is primarily a logical thesis, a ban on Is/Ought inferences which Hume derives from the logic of Ockham. NOFI is thus a variation on what Heathcote calls ‘Hume’s Master Argument’, which he also deploys to prove that conclusions about the future (and therefore a-temporal generalizations) cannot be derived by reason from premises about the past, and that conclusions about external objects or other minds cannot (...) be derived by reason from premises about impressions. Heathcote raises an important question. Having (apparently) argued that our inductive inferences are not justified by reason, Hume puts them down to Custom, and seems to suggest that we OUGHT to indulge this propensity but NOt the superstitious propensities that lead to religious belief. (Query: Why is it right to indulge one non-rational propensity but not the others?) Finally Heathcote argues that just as there are valid, but not formally valid, arguments taking us from claims about inferential relations to claims about what we ought to believe, so there may be valid, but not formally valid, arguments taking us from factual claims about some situation to claims about what we ought to do. -/- I reply that Hume does indeed have a Master Argument and that it does rely on logical principles but not on the logic of Ockham which had been largely forgotten by Hume’s day. Instead Hume relies on the idea widely believed in the 18th Century and taught to Hume at Edinburgh by his logic Professor Colin Drummond, that in a logically valid argument the conclusion is contained in the premises. I reconstruct Hume’s Master Argument using this principle. I draw a careful distinction between two theses: 1) that we cannot get from non-moral premises to moral conclusions with the aid of logic alone and 2) that we cannot get from non-moral premises to moral conclusions with aid of analytic bridge principles. Hume believed the first but not the second. What then is the role of NOFI in the larger argument of the Treatise? To show that the truths of ethics cannot be derived via logic from self-evident truths of some other kind and thus that they are not demonstrable. How can we make sense of Hume’s apparent belief that it is sometimes right to transcend reason and sometimes not? In the case of Custom, we live in a world governed by causal regularities, and, in such a world, induction is in fact a fairly reliable belief-forming mechanism. Thus a suitably qualified spectator (one aware of the kind of world we live in) would tend to approve of indulging it, even if it cannot be justified by reason. However, our superstitious propensities are (and can be known to be) unreliable, since they produce different and inconsistent results in different people. Thus it is it is wrong (something a suitably qualified spectator would disapprove of) to indulge the faculty of Superstition. I also take issue with Heathcote’s penchant for valid, but not formally valid, inferences. I supply the missing premises for Heathcote’s Is/Ought inferences and argue that they are either not true or not necessary. (shrink)

I argue 1) That in his celebrated Is/Ought passage, Hume employs ‘deduction’ in the strict sense, according to which if a conclusion B is justly or evidently deduced from a set of premises A, A cannot be true and B false, or B false and the premises A true. 2) That Hume was following the common custom of his times which sometimes employed ‘deduction’ in a strict sense to denote inferences in which, in the words of Dr Watts’ Logick, ‘the (...) premises, according to the reason of things, do really contain the conclusion that is deduced from them’; that although Hume sometimes uses ‘demonstrative argument’ as a synonym for ‘deduction’, like most of his contemporaries, he generally reserves the word ‘demonstration’ for deductive inferences in which the premises are both necessary and self-evident. 3) That Mr Hume did indeed mean to suggest that deductions from IS to OUGHT were ‘altogether inconceivable’ since if ought represents a new relation or affirmation, it cannot, in the strict sense, be justly deduced from premises which do not really contain it. 4) That in a large and liberal (or perhaps loose and promiscuous) sense Hume does deduce oughts and ought nots from observations concerning human affairs, but that the deductions in question are not inferences, but explanations, since in another sense of ‘deduce’, common in the Eighteenth Century, to deduce B from A is to trace B back to A or to explain B in terms of A; 5) That a small attention to the context of Hume’s remarks and to the logical notions on which they are based would subvert those vulgar systems of philosophy which exaggerate the distinction between fact and value; for just because it is ‘altogether inconceivable’ that the new relation or affirmation OUGHT should be a deduction from others that are entirely different from it, it does not follow that the facts represented by IS and IS NOT are at bottom any different from the values represented by OUGHT and OUGHT NOT. (shrink)

This is a response to Stephen Maitzen’s paper. ‘Moral Conclusions from Nonmoral Premises’. Maitzen thinks that No-Ought-From-Is is false. He does not dispute the formal proofs of Schurz and myself, but he thinks they are beside the point. For what the proponents of No-Ought-From-Is need to show is not that you cannot get SUBSTANTIVELY moral conclusions from FORMALLY non-moral premises but that you cannot get SUBSTANTIVELY moral conclusions from SUBSTANTIVELY non-moral premises. And he believes that he can derive substantively moral (...) conclusions from FORMALLY moral but SUBSTANTIVELY nonmoral premises. However his argument relies on what I call ‘taxonomic essentialism’, the thesis that sentences do not change their semantic characters from context to context or from world to world. In particular, they do not change their META-ETHICAL status from context to context or world to world. If a sentence is non-moral at one world it is non-moral at all the rest. This thesis leads to contradictions (with some propositions as both moral and non-moral) and even if (as is perhaps possible) these contradictions can be avoided, it leads to further consequences that are palpably absurd. Thus It may be possible to derive substantively moral conclusions from premises that are not substantively moral, but if it is, Maitzen has failed to prove the point. (shrink)

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. (shrink)

Elizabeth Anscombe tangos with Hume in the middle of her march toward the three theses of "Modern Moral Philosophy" that we should abandon moral philosophy "until we have an adequate philosophy of psychology"; that the concepts of moral obligation and moral duty, of what is morally right and wrong, and of the moral sense of 'ought' "ought to be jettisoned if this is psychologically possible;" and that "the differences between the well-known English writers on moral philosophy from Sidgwick to the (...) present day are of little importance." But the tango could have been a waltz: Hume could embrace at least the first two theses with pleasure. Indeed, Hume pursues the kind of philosophy of psychology that Anscombe recommends and offers resources for developing her reflections on the relationship between happiness, human need, and our particular desires. (shrink)

Hume first raised the "is-ought" problem in a famous paragraph in A Treatise of Human Nature. What is open to question is Hume's assumption that the relationship between is propositions and ought propositions in ordinary moral discussion is or is intended to be one of logical deduction. It is this assumption that I wish to address in this article. It has been challenged most powerfully by Bernard Lonergan through his notions of sublation and the four levels of consciousness.

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)

In this essay we argue that if the covering-law model of moral justification is correct, Hume's "is"-"ought" paragraph calls the possibility of a justifiable theory of moral obligation in doubt. In the first section we delineate Hume's doubts. In the second section we develop a skeptical solution to those doubts.

Unlike old soldiers, the rhetoric of the great neither dies nor fades away. And so Hume's celebrated ‘is-ought’ passage still provokes debate.Hume was worried about the relation between ought statements and those supporting them: between ‘tolerence brings peace’ or ‘is God's will’, and ‘so one ought to be tolerant’. He denies the deducibility of the latter from the former, as the ‘ought’ expresses ‘a new relation or affirmation’, ‘entirely different from the others’. And this is commonly taken as saying that (...) the ought statement is ‘different’ and non-deducible, because it is no longer a ‘purely factual statement’, to wit one that makes another ordinarily testable truth claim.However, recent criticism, by W. D. Hudson and others, points out that Hume says other things seemingly inconsistent with this. In the passage, he mentions ‘ought’ and ‘virtue’ interchangeably, and ‘tolerance is virtuous’ as in the same boat as ‘one ought to be tolerant’. But, also, he treats the virtue of an action as sensibly discernible by the approbation which it evokes, and takes us to mean by a virtuous action that we will approve of it on contemplation. (shrink)

One of the most persistent issues of contemporary moral theory is the possibility of inferring moral judgments from factual nonmoral judgments. Another way of stating this issue is to inquire into the possibility of inferring "ought-judgments" from "is-judgments." It is generally accepted that the first person to deny the possibility of this inference was David Hume. The denial is supposed to be articulated in the last paragraph of the section of A Treatise of Human Nature entitled "Moral Distinctions not derived (...) from Reason," pages 469-470 in the Selby-Bigge edition. Hereafter I shall refer to this paragraph, the "is-oughtparagraph," as (I-0). The purpose of this article is to show that in (I-0) Hume makes no such denial, and to outline the implications of this revelation. (shrink)

There are eight major misconceptions about Hume's moral theory. First,many believe that there is no essential difference between the Treatise and the Enquiry. Second, some commentators believe that Hume has an extraordinary theory about the moral point of view. Third, many assume that Hume has an explicit theory of moral judgment. Fourth, several commentators have attributed to Hume a multiple theory about the relationship between moral judgment and moral sentiment. Fifth, some assert that Hume has a qualified- or ideal-spectator theory (...) of moral judgment based upon the extraordinary theory about the moral point of view. Sixth, some assert that Hume has an emotivist theory of moral judgment. Seventh, several commentatorshave either accused Hume of violating his own argument against inferring "ought" from "is" or they have sought to show how Hume is justified in making an inference from "is" to "ought" by having the "is" refer to a special class of statements about feelings. Finally, some assert that Hume is a utilitarian in his theory of moral judgment. I shall comment briefly on each of these misconceptions. (shrink)

In this paper, I argue that David Hume's is-ought problem stems from morality as a simplifying framework. Morality is the attempt to describe human behaviour and its relation to nature through a court framework, dating to prehistoric times. Such a court does not really exist, hence we are not referring to anything directly when we make moral statements, and therefore 'is' and 'ought' do not align. The solution is to replace morality with what it's really trying to describe: patterns in (...) individual behaviour. (shrink)