Is/Ought

In his book The Ethical Project, Philip Kitcher (2011) offers a naturalistic account of Ethics, which he dubs Pragmatic Naturalism. Based in evidence from primatology, archeology and anthropology, and some speculation from evolutionary biology, his account is intended to be normative and not merely descriptive, therefore it has to fulfill a challenge posed by Hume (1978) that any normative naturalistic account of ethics has to fulfill: how to bridge the is-ought gap, i.e. how can a prescription of an ethical practice be made from purely descriptive premises. The purpose of this paper is to explore the details of how this challenge could be met using the framework of pragmatic naturalism. My answer will be that pragmatic naturalism is able to give a logically valid argument from ‘is’ to ‘ought’ using descriptive claims and conceptual truths as premises. Its normative force is not delivered as an absolute authority—as some moral realists would like—but that is not a problem for pragmatic naturalism, since it does not have that aim.

Jeremy Bentham es unánimemente reconocido como un filósofo político y del derecho de primera fila; también es muy reconocido como economista o teórico de la economía; desde luego, es considerado como uno de los grandes reformadores sociales del siglo XIX; incluso, recientemente, desde el último cuarto del siglo XX, ha comenzado a ser visto como uno de los grandes expertos clásicos en historia de la sexualidad y como un pensador radical en este ámbito. Pero ¿fue Bentham un gran filósofo, especialmente un gran filósofo moral? Palabras clave: Jeremy Bentham; David Hume; utilitarismo del acto; utilitarismo de la regla; pluralismo ético; niveles de moralidad.

Is/Ought survey article, presupposing a little more logical sophistication that the above paper for Philosophy Now. For the Academia version  I have added footnotes  referencing the papers in which I argue at length for my more contentious claims.

For papers which expand on  the historical Hume and the implications of No-Ought-From-Is for contemporary Meta-Ethics, see below  'Letter from a Gentleman' and 'Snare's Puzzle/Hume's Purpose'

Bu araştırma, ilk defa David Hume'un tartışmaya açtığı problem olarak bilinen 'Olgu-Değer Problemi' veya diğer bir ifadesiyle 'Olan-Olması Gereken Problemi'nin tarihsel ve kavramsal incelemesini içerir. Bu bağlamda, ilk bölümde 'olgu-değer ayrımı' isimlendirmesiyle ahlâk felsefesine kavramsal olarak tartışmaya açan David Hume'un ahlâk felsefesi ve olgu-değer problemini tartıştığı pasaja yer verildi. Yine bu bölüm içerisinde, Hume'a hiç atıf yapmadan olgu-değer ayrımına benzer bir şekilde iyi kavramını inceleyen George Edward Moore'un ahlâk felsefesinde, olan-olması gereken ayrımının ne şekilde ele alındığı incelendi. İkinci bölüm, olgu-değer probleminin çağdaş ahlâk felsefesinde nasıl ele alındığına ayrılmıştır. Hume'dan tevarüs eden bu problemin, çağdaş ahlâk filozoflarının yoğun ve ciddi olarak gündemlerinde olduğu görülmektedir. Bu minvalde, öne çıkan bazı filozofların olgu-değer problemine ilişkin metinleri incelendi. Son bölümde ise, çağdaş ahlâk felsefesinin önemli isimlerinden Alasdair MacIntyre mezkûr problem etrafında incelenecektir. Bu bağlamda, öncelikle MacIntyre'ın ahlâk anlayışına, erdem ahlâkına, giriş yapıldıktan sonra MacIntyre'ın olgu-değer problemine olan yaklaşımı, gerek kitapları gerekse probleme ilişkin yazmış olduğu makalesi üzerinden takip edilecektir. Bu bölümün son kısmında ise, bu problem etrafında MacIntyre'a yöneltilen değerlendirmelere, eleştirilere yer verildi.

Almost sixty years ago Philippa Foot published an article that began: To many people it seems that the most notable advance in moral philosophy during the past fifty years or so has been the refutation of naturalism; and they are a little shocked that at this late date such an issue should be reopened. It is easy to understand their attitude: given certain apparently unquestionable assumptions, it would be about as sensible to try to reintroduce naturalism as to try to square the circle. Those who see it like this have satisfied themselves that they know in advance that any naturalistic theory must have a catch in it somewhere, and are put out at having to waste more time exposing an old fallacy. This paper is an attempt to persuade them to look critically at the premises on which their arguments are based. 1 The paper in question was one of a number written by Foot around the time that were highly successful in reopening the issue of naturalism in ethics. Nowadays no one can just take it for granted that naturalism has been refuted, that there is a sharp distinction (or indeed any clear distinction) between fact and value or that it is impossible to derive an 'ought' from an 'is'. This is not to say that the naturalists have been completely victorious, of course; only that naturalism is today a live option. I shall argue that Foot's paper contains an important insight and an equally important mistake; and that the insight and the mistake are linked. I believe that the thinking behind it has influenced the subsequent course of moral philosophy to a quite remarkable extent and that this has been in some ways beneficial and in some ways harmful – not surprisingly, if I am right in seeing it as containing both truth and error. I do not want to exaggerate the influence of this one paper 2 but I do not know of any other that so neatly encapsulates the coupled insight and mistake. The anti-naturalism that Foot is attacking she characterises as follows: It would not be an exaggeration to say that the whole of moral philosophy, as it is now widely taught, rests on a contrast between statements of fact and evaluations, which runs something like this: The truth or falsity of statements of fact is shewn by means of evidence; and what counts as evidence is laid down in the meaning of the expressions occurring in the statement of fact … It follows that no two people can make the same statement and count completely different things as evidence; in the end one at least of them could be convicted of linguistic ignorance. It also follows that if a man is given good evidence for a factual conclusion he cannot just refuse to accept the conclusion on the ground that in his scheme of things this evidence is not evidence at all. 3 But, on the view she is criticising, [w]ith evaluations, however, it is different. An evaluation is not connected logically with the factual statements on which it is based. One man may say that a thing is good because of some fact about it, and another may refuse to take that fact as any evidence, for nothing is laid down in the meaning of 'good' which connects it with one piece of 'evidence' rather than another. It follows that a moral eccentric could argue to moral conclusions from quite idiosyncratic premises; he could say, for instance, that a man was a good man because he clasped and unclasped his hands and never turned NNE after

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.

A brief conspectus of my views on Hume, Is and Ought, omitting most  of the complications required to answer Arthur Prior (and saying nothing about Gerhard Schurz whose ideas would be a little too complicated to explain to the  intended audience). Suitable for first or second year undergraduates or intelligent laypeople with some knowledge of  philosophy but not much of formal logic.

My first paper on the Is/Ought issue. The young Arthur Prior endorsed the Autonomy of Ethics, in the form of Hume’s No-Ought-From-Is (NOFI) but the later Prior developed a seemingly devastating counter-argument. I defend Prior's earlier logical thesis (albeit in a modified form) against his later self. However it is important to distinguish between three versions of the Autonomy of Ethics: Ontological, Semantic and Ontological.  Ontological Autonomy is the thesis that moral judgments, to be true, must answer to a realm of sui generis non-natural PROPERTIES. Semantic autonomy insists on a realm of sui generis non-natural PREDICATES which do not mean the same as any natural counterparts. Logical Autonomy maintains that moral conclusions cannot be derived from non-moral premises.-moral premises with the aid of logic alone. Logical Autonomy does not entail Semantic Autonomy and Semantic Autonomy does not entail Ontological Autonomy. But, given some plausible assumptions Ontological Autonomy entails Semantic Autonomy and given the conservativeness of logic – the idea that in a valid argument you don’t get out what you haven’t put in – Semantic Autonomy entails Logical Autonomy. So if Logical Autonomy is false – as Prior appears to prove – then Semantic and Ontological Autonomy would appear to be false too!  I develop a version of Logical Autonomy (or NOFI) and vindicate it against Prior’s counterexamples, which are also counterexamples to the conservativeness of logic as traditionally conceived. The key concept here is an idea derived in part from Quine - that of INFERENCE-RELATIVE VACUITY. I prove that you cannot derive conclusions in which the moral terms appear non-vacuously from premises from which they are absent.  But this is because you cannot derive conclusions in which ANY (non-logical) terms appear non-vacuously from premises from which they are absent Thus NOFI or Logical  Autonomy comes out as an instance of the conservativeness of logic.  This means that the reverse entailment that I have suggested turns out to be a mistake.  The falsehood of Logical Autonomy would not entail either the falsehood Semantic Autonomy or the falsehood of Ontological Autonomy, since Semantic Autonomy only entails Logical Autonomy with the aid of the conservativeness of logic of which Logical Autonomy is simply an instance.  Thus NOFI or Logical Autonomy is vindicated, but it turns out to be a less world-shattering thesis than some have supposed. It provides no support for either non-cognitivism or non-naturalism.

Survey talk delivered to the Cambridge Meta-Ethics group in 2011.  After some brief remarks on the ambiguities in Hume's version of No-Ought-From-Is,  I outline Prior's paradox and discuss the various responses, principally  mine (the New Zealand Plan) and  Schurz's (the Austrian Plan).  In this text I add seven appendices drawn mainly from my introduction to Hume On Is and Ought, amplifying the argument, discussing matters arising and outlining rival approaches to the problem, principally the relevantist solution,  due to Ed Mares, and the Inference Barrier solution (the Scottish/Australian Plan) due to Gillian Russell and Greg Restall.  I also discuss the work of Stephen Maitzen and Mark Nelson.

In this talk I emphasize the logical aspects of the issue.

Drafts of my contributions to this debate available above in 'Papers'.  'The Triviality of Hume's Law', 'Coda: Truth and Consequences' and 'Subtance, Taxonomy, Content and Consequence' emphasize the logical and meta-ethical aspects of the the issue, whilst 'Letter From a Gentleman' and 'Snare's Puzzle/Hume's Purpose' emphasize meta-ethics and the historical Hume. 'Comments on "Hume's Master Argument"' deals  with all three themes.  The kick-off paper is 'Logic and the Autonomy of Ethics' (1989).  The last in the sequence is 'Hume on is and Ought: Logic Promises and the Duke of Wellington'.

Hume seems to contend that you can’t get an ought from an is.  Searle professed to prove otherwise, deriving a conclusion about obligations from a premise about promises.  Since (as Schurz and I have shown) you can’t derive a substantive ought from an is by logic alone, Searle is best construed as claiming that there are analytic bridge principles linking premises about promises to conclusions about obligations. But we can no more derive a moral obligation to pay up from the fact that a promise has been made than we can derive a duty to fight a duel from the fact that a challenge has been issued – just conclusions about what we ought to do according to the rules of the relevant games. Hume suggests bridge principles that would take us from the rules of the games to conclusions about duties, but these principles are false. My argument features an obstreperous earl, an anarchist philosopher and a dueling Prime Minister
""

This contains
1) A methodological meditation in blank verse, defending a broadly collegial vision of the history of philosophy, as applied specifically to Hume.
2) A conspectus of the debate on the role of No-Ought-From-Is within the Treatise itself.  What does Hume mean by  ‘deduction’ and are the deductions from Is to Ought actually or only seemingly inconceivable?  Why after having made so much of NOFI in the Treatise does Hume drop it in the EPM?
3) A summary of the debate surrounding Heathcote’s contention that NOFI is an instance of Hume’s Ockhamist ‘Master Argument’.
4) A potted history of the reception of NOFI from Reid and Bentham to Hudson.
4) A conspectus of the debate on the meta-ethical implications of NOFI, specifically targeting the idea that it implies either non-naturalism, non-cognitivism, expressivism or a fact/value split (I say ‘none of the above’).
5) A survey of four major responses to Prior’s famous counterexamples both to NOFI and to the conservativeness of logic (the thesis that in a valid argument you don’t get out what you haven’t put in). These are the New Zealand Plan (due to me) which devises and proves an amended version of NOFI  (No-Non-Vacuous-Ought-From-Is), the Austrian Plan (due to Gerhard Schurz) which devises and proves another version of NOFI (No-Ought-Relevant-Ought-From-Is), the Scottish/Australian Plan (due to Gillian Russell and Greg Restall) which defends a revised version of NOFI by constructing and proving an implication barrier thesis, and the relevantist solution, (represented in this collection by Edwin Mares) which defeats Prior’s dilemma by lopping off one of its horns. 
6) A summary of the debate about Stephen Maitzen’s interesting claim that though it may be impossible to derive  substantively moral conclusions from FORMALLY non-moral premises, it is possible to derive substantively moral conclusions from SUBSTANTIVELY  non-moral premises, thus rendering the formal proofs of his opponents redundant. (I say his argument presupposes an implausible form of taxonomic essentialism.)

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.

Mackie’s claim that in general courage benefits its possessor seems inconsistent with his ‘error theory’ of value.  But how plausible is it in itself?  I suggest that his arguments for the claim fail in the same way as the arguments of those who more explicitly embrace ‘virtue ethics’ fail.  We do not know any way of objectively weighing risks against other considerations, of deciding whether something is ‘worth the risk’.  Since I have no PROOF that there could not be a way, I prefer to speak of ‘ignorance’ rather than ‘error’ here.

I argue that Mackie's thesis about courage and self-interest is neither consistent with his 'error theory' of value nor convincing in itself.  The question of the objectivity of value needs to be distinguished from that of whether one value can objectively outweigh or outrank another.  This is so even when the only values under consideration are self-interested ones.

I argue that No-Ought-From-Is (in the sense that I believe it) is a relatively trivial affair. Of course, when people try to derive substantive or non-vacuous moral conclusions from non-moral premises, they are making a mistake. But No-Non-Vacuous-Ought-From-Is is meta-ethically inert. It tells us nothing about the nature of the moral concepts. It neither refutes naturalism nor supports non-cognitivism. And this is not very surprising since it is merely an instance of an updated version of the conservativeness of logic (in a logically valid inference you don’t get out what you haven’t put in): so long as the expressions F are non-logical, you cannot get non-vacuous F-conclusions from non-F premises. However, the triviality of No-Non-Vacuous-Ought-From-Is is important and its non-profundity profound. No-Ought-From-Is is widely supposed to tell us something significant about the nature of the moral concepts. If, in fact, it tells us nothing, this is a point well worth shouting from the housetops. This brings me to my dispute with Gerhard Schurz  who has proved a related version of  No-Ought-From-Is, No-Ought-Relevant-Ought-From-Is, a proof which relaxes my assumption that ‘ought’ should not be treated as a logical constant. But if ought is not a logical expression then it does not really matter much that No-Ought-From-Is would be salvageable even if it were. Furthermore, Schurz’s proof depends on special features of the moral concepts and this might afford the basis for an abductive argument to something like non-cognitivism. As an error theorist, and therefore a cognitivist, I object. Finally I take a dim view of deontic logic. Many of its leading principles are false, bordering on the nonsensical, and even the reasonably plausible ones are subject to devastating counter-examples.

I maintain as against Annette Baier and David Owen

(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
(2) That Hume was following the common custom of his times which sometimes employed ‘deduction’ in a strict sense to denote inferences in which the premises cannot be true and the conclusion false, since, 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’;.
(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 indeed deduce oughts and ought nots from observations concerning human affairs, but that the deductions in question are not general 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 indeed 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.

However, in this version of the paper there is more about the various senses of 'deduction' employed in the 18th Century; more about  18th Century logic, more about deductive arguments  in both Hume and  his contemporaries (often with contingent and sometimes false premises); more Gibbon, more Reid and more from Hume's History as well as an analysis of EHU 8.2  as a dilemmatic disproof of God's existence.  Much more fun , in short for the dedicated Humean or early modernist.

This is the uncut version of my  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

This is the course-book for my 'Themes from Hume' paper, which is largely based on my two edited collections, 'Hume, Motivation and Virtue' (HMV) and 'Hume on Is and Ought' (HIO). It contains  most of my papers on  Is and Ought, the Slavery of Reason thesis and the  Motivation Argument, including  'Directors Cut' versions of my contributions to HIO and HMV, and my first paper on these topics: 'Logic and  the Basis of Ethics' . It also contains a couple of  papers on  G.E Moore and the  Naturalistic Fallacy,  and what I call the Generalised Hume Thesis  (Beliefs of kind X are not the products of reason but of some non-rational causal mechanisms Y. Sometimes Hume seems to approve of going with the flow of the non-rational causal mechanisms and sometimes he does not. Has he a principled reason for his preferences?) The course-book  also includes my essay on Hume and Jane Austen. Thus in the current absence of a 'Collected Papers' it is a useful compendium for anyone interested in my views on these subjects.

COURSE-BLURB
This is a paper straddling metaethics (the nature and justification of moral judgements), the history of philosophy and the philosophy of logic. It deals with three themes from the work of David Hume (1711-1776) together with "matters arising" from the Humean agenda:

The Slavery of Reason Thesis ("reason is and ought only to be the slave of the passions"). What does this mean? Is the Slavery of Reason Thesis (or something like it) correct? And what (if anything) does this suggest about the nature of ethics?
The Motivation (or Influence) Argument:
Morals have an influence on the actions and affections. [Premise]
Reason alone, as we have already proved, can never have any such influence. [Premise]
Morals...cannot be derived from reason
What exactly is this argument supposed to prove? Does it succeed? If not, is there a decent argument in the neighbourhood that proves something similar? Can it be used to support non-cognitivism, the idea that moral judgements are neither true nor false?
Hume's No-Ought-From-Is thesis: "[It] seems altogether inconceivable", says David Hume, "that this new relation or affirmation [ought] can be a deduction from others, which are entirely different from it". What did Hume mean by this? Can you deduce an ought from an is? If not, why not? And what (if anything) does this suggest about the status of moral judgements? We focus on the idea, common in the 18th century, that logic is conservative - that in a valid inference you cannot get out what you haven't put in. In a famous paper the great New Zealand logician Arthur Prior challenged No-Ought-From-Is, along with the concept of conservativeness. We discuss the responses of Pigden, Schurz, Greg Restall and Gillian Russell, who all try to vindicate different versions of No-Ought-From-Is in the face of Prior's counterexamples.

""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.""

"A Letter from a Gentleman in Dunedin To a Lady in the Country ( the late Professor Baier) With Remarks on the Meaning of Deduction in the celebrated Mr Hume's A Treatise of Human Nature, 3.3.1, and in the discourse of the Eighteenth Century in general. Wherein the various senses of deduction deriv'd from the Best Authors are carefully distinguish'd., and the Consequences for the Study of Ethicks are deduced.


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 generally 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.
"