Various Readings of Hume's "Is-Ought" Principle.

[Veritas Aequitas]

Most posters here I note jumped to one fanatical view on Hume's "Is-Ought" Principle without considering there are many contested views.

My contention is the most popular view labelled in terms of Hume's Law or Hume's guillotine [merely from one paragraph] is not representative of Hume overall intention.

To understand what Hume's view of the is-ought dichotomy one need to read and grasp Hume's view from his Treatise and Enquiry.

Here is an extract from SEP on the various readings of Hume's "Is-Ought" Principle.

Hume famously closes the section of the Treatise that argues against moral rationalism by observing that other systems of moral philosophy, proceeding in the ordinary way of reasoning, at some point make an unremarked transition from premises whose parts are linked only by “is” to conclusions whose parts are linked by “ought” (expressing a new relation) — a deduction that seems to Hume “altogether inconceivable” (T3.1.1.27).
Attention to this transition would “subvert all the vulgar systems of morality, and let us see, that the distinction of vice and virtue is not founded merely on the relations of objects, nor is perceiv’d by reason” (ibid.)

Few passages in Hume’s work have generated more interpretive controversy.

1. According to the dominant twentieth-century interpretation, Hume says here that no ought-judgment may be correctly inferred from a set of premises expressed only in terms of ‘is,’ and the vulgar systems of morality commit this logical fallacy.
This is usually thought to mean something much more general:
that no ethical or indeed evaluative conclusion whatsoever may be validly inferred from any set of purely factual premises.
A number of present-day philosophers, including R. M. Hare, endorse this putative thesis of logic, calling it “Hume’s Law.” [or Hume's Guilotine]
(As Francis Snare observes, on this reading Hume must simply assume that no purely factual propositions are themselves evaluative, as he does not argue for this.)
Putative = generally considered or reputed to be.

2. Some interpreters think Hume commits himself here to a non-propositional or noncognitivist view of moral judgment — the view that moral judgments do not state facts and are not truth-evaluable.
(If Hume has already used the famous argument about the motivational influence of morals to establish noncognitivism, then the is/ought paragraph may merely draw out a trivial consequence of it.
If moral evaluations are merely expressions of feeling without propositional content, then of course they cannot be inferred from any propositional premises.)

• Note: Non-cognitivism is the meta-ethical view that ethical sentences do not express propositions (i.e., statements) and thus cannot be true or false (they are not truth-apt). A noncognitivist denies the cognitivist claim that "moral judgments are capable of being objectively true, because they describe some feature of the world".[1] If moral statements cannot be true, and if one cannot know something that is not true, noncognitivism implies that moral knowledge is impossible.
  -wiki

3. Some see the paragraph as denying ethical realism, excluding values from the domain of facts.

4. Other interpreters — the more cognitivist ones — see the paragraph about ‘is’ and ‘ought’ as doing none of the above.

5. Some read it as simply providing further support for Hume’s extensive argument that moral properties are not discernible by demonstrative reason, leaving open whether ethical evaluations may be conclusions of cogent probable arguments.

5. Others interpret it as making a point about the original discovery of virtue and vice, which must involve the use of sentiment.
On this view, one cannot make the initial discovery of moral properties by inference from nonmoral premises using reason alone; rather, one requires some input from sentiment.
It is not simply by reasoning from the abstract and causal relations one has discovered that one comes to have the ideas of virtue and vice; one must respond to such information with feelings of approval and disapproval.
Note that on this reading it is compatible with the is/ought paragraph that once a person has the moral concepts as the result of prior experience of the moral sentiments, he or she may reach some particular moral conclusions by inference from causal, factual premises (stated in terms of ‘is’) about the effects of character traits on the sentiments of observers.
They point out that Hume himself makes such inferences frequently in his writings.

From my reading of both Hume's book, i.e. the Treatise and Enquiry I am aligned with the views as in 5.

[Skepdick]

You are failing to divorce understanding the principle from applying the principle.

There's a big oopsie when you ask the question "Ought we apply the is-ought principle?"

That oopisie is precisely the question of intent.

[Veritas Aequitas]

Here is a comment on Hume's later views from the Enquiry over those from his earlier Treatise.

What is noted is this;

What I noted is Hume objected to the Christians' or others who advocated absolute moral objective in relation to the is-ought issue.

However Hume did not object to relative moral objectives as indicated below, i.e. seeking what is common within all humans and establishing that as the foundation of ethics.

Late in his life Hume deemed the Enquiry concerning the Principles of Morals his best work, and in style it is a model of elegance and subtlety.

• His method in that work differs from that of the Treatise: instead of explicating the nature of virtue and vice and our knowledge of them in terms of underlying features of the human mind,
  he proposes to collect all the traits we know from common sense to be virtues and vices,
  observe what those in each group have in common,
  and from that observation discover the “foundation of ethics”

(EPM 1.10).

In the moral Enquiry Hume omits all arguments to show that reason alone does not move us to act; so the Representation Argument about the irrelevance of reason to passions and actions is absent.
Without it he has no support for his direct argument that moral goodness and evil are not identical with reasonableness and unreasonableness, which relies on it for its key premise; and that too is absent from EPM.

In the moral Enquiry Hume is more explicit about what he takes to be the errors of Christian (or, more cautiously, Roman Catholic) moralists.
Not only have they [Christian Moralists] elevated craven humility to the status of a virtue, which he hints in the Treatise is a mistake, but they also favor penance, fasting, and other “monkish virtues” that are in fact disapproved by all reasonable folk for their uselessness and disagreeableness, and so are in fact vices. [Treatise X Pt.I]

From the above I had argued Hume's Law re 'is-ought' is focus mainly on the Christian Moralists rather than objecting there is no moral objectives.

Views?

[Sculptor]

Here is a comment on Hume's later views from the Enquiry over those from his earlier Treatise.

What is noted is this;

What I noted is Hume objected to the Christians' or others who advocated absolute moral objective in relation to the is-ought issue.

However Hume did not object to relative moral objectives as indicated below, i.e. seeking what is common within all humans and establishing that as the foundation of ethics.

Late in his life Hume deemed the Enquiry concerning the Principles of Morals his best work, and in style it is a model of elegance and subtlety.

• His method in that work differs from that of the Treatise: instead of explicating the nature of virtue and vice and our knowledge of them in terms of underlying features of the human mind,
  he proposes to collect all the traits we know from common sense to be virtues and vices,
  observe what those in each group have in common,
  and from that observation discover the “foundation of ethics”

(EPM 1.10).

In the moral Enquiry Hume omits all arguments to show that reason alone does not move us to act; so the Representation Argument about the irrelevance of reason to passions and actions is absent.
Without it he has no support for his direct argument that moral goodness and evil are not identical with reasonableness and unreasonableness, which relies on it for its key premise; and that too is absent from EPM.

In the moral Enquiry Hume is more explicit about what he takes to be the errors of Christian (or, more cautiously, Roman Catholic) moralists.
Not only have they [Christian Moralists] elevated craven humility to the status of a virtue, which he hints in the Treatise is a mistake, but they also favor penance, fasting, and other “monkish virtues” that are in fact disapproved by all reasonable folk for their uselessness and disagreeableness, and so are in fact vices. [Treatise X Pt.I]

From the above I had argued Hume's Law re 'is-ought' is focus mainly on the Christian Moralists rather than objecting there is no moral objectives.

Views?

The is/ought objection simply stated that just because a thing is the case does not mean we ought to follow a particular course of action.
The is nothing intrinsically different about Christianity, except that they use this line of argument to justify a morally objective position. The reason for this is that since god is the author of nature as well as the supposed author of the Book, then any observations of fact that can be leveled to support a moral line of prescription can be taken from facts. In effect god has designed the world such that moralists who believe are to be relied on simply to reveal the absolute and objective moral truths.
This is/ought problem is a recognition that "IS" is not enough, no matter that is a Christian observation or no.
A moral injunction has to be justified on other grounds, such as the consequence, the mitigations of circumstance and the utility of that moral choice. This does not qualify it as objective, but relative and subjective. Simply it depends.

For example just because slavery "IS" evil (let's imagine that you could prove such a thing), it would not automatically be a license to universal manumission and let slaves be forced to immediately find their own way to face death and poverty.
Just because smoking is harmful does not mean you can ban people from smoking.
Between the harm of smoking and the proscription of it there exists a whole host of factors both rational and emotional that are not so easy to unpack.

[Veritas Aequitas]

The is/ought objection simply stated that just because a thing is the case does not mean we ought to follow a particular course of action.

The is nothing intrinsically different about Christianity, except that they use this line of argument to justify a morally objective position. The reason for this is that since god is the author of nature as well as the supposed author of the Book, then any observations of fact that can be leveled to support a moral line of prescription can be taken from facts. In effect god has designed the world such that moralists who believe are to be relied on simply to reveal the absolute and objective moral truths.
This is/ought problem is a recognition that "IS" is not enough, no matter that is a Christian observation or no.

A moral injunction has to be justified on other grounds, such as the consequence, the mitigations of circumstance and the utility of that moral choice. This does not qualify it as objective, but relative and subjective. Simply it depends.

For example just because slavery "IS" evil (let's imagine that you could prove such a thing), it would not automatically be a license to universal manumission and let slaves be forced to immediately find their own way to face death and poverty.
Just because smoking is harmful does not mean you can ban people from smoking.
Between the harm of smoking and the proscription of it there exists a whole host of factors both rational and emotional that are not so easy to unpack.

You claimed to be an old-fart on Hume's Principles of Morals but your above points re is-ought are not in alignment with Hume's intended thoughts as expressed in his Treatise and Enquiry.

I had reread and refreshed Hume's Treatise and the Enquiry.

Note I presented in the OP various readings [interpretations] by different philosophers on the is-ought issue and I agreed with point 5 in the OP.
Here is point 5 again.

5. Others interpret it as making a point about the original discovery of virtue and vice, which must involve the use of sentiment.

On this view, one cannot make the initial discovery of moral properties by inference from nonmoral premises using reason alone; rather, one requires some input from sentiment.

It is not simply by reasoning from the abstract and causal relations one has discovered that one comes to have the ideas of virtue and vice; one must respond to such information with feelings of approval and disapproval.

Note that on this reading it is compatible with the is/ought paragraph that once a person has the moral concepts as the result of prior experience of the moral sentiments, he or she may reach some particular moral conclusions by inference from causal, factual premises (stated in terms of ‘is’) about the effects of character traits on the sentiments of observers.

They point out that Hume himself makes such inferences frequently in his writings.

Hume stated enforcement of moral injunctions/properties [slavery, crimes, etc.] by external parties [government, etc.] but that is secondary in contrast to the moral sentiments by the individual within his mind.

Hume's main contention is moral properties cannot be derived from reason alone. He condemned previous philosophers who relied on reason alone - the dogmatic rationalists.
There is no direct relationship between the empirical and reason, what is relevant here are sentiments which triggers reason.
The moral impulse comes originally from sentiment and this must then be complemented with reason.
This moral sentiment is triggered by sympathy [empathy in modern term]. Note my countless reference to mirror neurons and empathy.
When this sentiment is triggered, that sentiment triggers reason which then becomes an ought [by implication].

From the individual's sentiment and sympathy an ought is triggered to motivate action. That ought is objectified when verified with the empirical evidences from the collective [is].

• Example:It is sympathy [empathy] that triggers pains in the individual when he observed and sympathize [empathize] with sufferings of the slave[s].
  Obviously the individual who has the above sentiments pains will want to avoid those pains, and thus it become an 'ought' for the individual.
  In addition, from empirical evidence the above experiences are common within the majority.

Note this point I highlighted earlier;

His method in that work differs from that of the Treatise: instead of explicating the nature of virtue and vice and our knowledge of them in terms of underlying features of the human mind,
he proposes to collect all the traits we know from common sense to be virtues and vices,
observe what those in each group have in common,
and from that observation discover the “foundation of ethics.”
(EPM 1.10).

The foundations of ethics are thus oughts that are shared by the collective* as justified from empirical evidences and philosophical reasonings. Hume also mentioned society, the collective, humanity and the human species in his works.
Hume did not mention 'ought' but he stated there is an imperative to act morally by the individual, thus an 'ought'.

The above is the general theme of Hume's morality.
Hume was very critical of theistic morality which simply make the connect of the relationship between the empirical and reason without justifications.
There are loads of diverse points within the Treatise and Enquiry - no time to discuss them less you dig into them to counter my views above.

My personal view is Hume's presented various disjointed elements and principles of morality, thus is not systematic nor sufficiently complete in contrast to Kant's systematic System of Morality/Ethics.

Suggest you reread Hume's Treatise [re Morality] and the Enquiry line by line which I had done.

[Sculptor]

The is/ought objection simply stated that just because a thing is the case does not mean we ought to follow a particular course of action.

The is nothing intrinsically different about Christianity, except that they use this line of argument to justify a morally objective position. The reason for this is that since god is the author of nature as well as the supposed author of the Book, then any observations of fact that can be leveled to support a moral line of prescription can be taken from facts. In effect god has designed the world such that moralists who believe are to be relied on simply to reveal the absolute and objective moral truths.
This is/ought problem is a recognition that "IS" is not enough, no matter that is a Christian observation or no.

A moral injunction has to be justified on other grounds, such as the consequence, the mitigations of circumstance and the utility of that moral choice. This does not qualify it as objective, but relative and subjective. Simply it depends.

For example just because slavery "IS" evil (let's imagine that you could prove such a thing), it would not automatically be a license to universal manumission and let slaves be forced to immediately find their own way to face death and poverty.
Just because smoking is harmful does not mean you can ban people from smoking.
Between the harm of smoking and the proscription of it there exists a whole host of factors both rational and emotional that are not so easy to unpack.

You claimed to be an old-fart on Hume's Principles of Morals but your above points re is-ought are not in alignment with Hume's intended thoughts as expressed in his Treatise and Enquiry.

Not my words at all.

I had reread and refreshed Hume's Treatise and the Enquiry.

Note I presented in the OP various readings [interpretations] by different philosophers on the is-ought issue and I agreed with point 5 in the OP.
Here is point 5 again.

5. Others interpret it as making a point about the original discovery of virtue and vice, which must involve the use of sentiment.

On this view, one cannot make the initial discovery of moral properties by inference from nonmoral premises using reason alone; rather, one requires some input from sentiment.

It is not simply by reasoning from the abstract and causal relations one has discovered that one comes to have the ideas of virtue and vice; one must respond to such information with feelings of approval and disapproval.

Note that on this reading it is compatible with the is/ought paragraph that once a person has the moral concepts as the result of prior experience of the moral sentiments, he or she may reach some particular moral conclusions by inference from causal, factual premises (stated in terms of ‘is’) about the effects of character traits on the sentiments of observers.

They point out that Hume himself makes such inferences frequently in his writings.

Hume stated enforcement of moral injunctions/properties [slavery, crimes, etc.] by external parties [government, etc.] but that is secondary in contrast to the moral sentiments by the individual within his mind.

Hume's main contention is moral properties cannot be derived from reason alone. He condemned previous philosophers who relied on reason alone - the dogmatic rationalists.
There is no direct relationship between the empirical and reason, what is relevant here are sentiments which triggers reason.
The moral impulse comes originally from sentiment and this must then be complemented with reason.
This moral sentiment is triggered by sympathy [empathy in modern term]. Note my countless reference to mirror neurons and empathy.
When this sentiment is triggered, that sentiment triggers reason which then becomes an ought [by implication].

From the individual's sentiment and sympathy an ought is triggered to motivate action. That ought is objectified when verified with the empirical evidences from the collective [is].

• Example:It is sympathy [empathy] that triggers pains in the individual when he observed and sympathize [empathize] with sufferings of the slave[s].
  Obviously the individual who has the above sentiments pains will want to avoid those pains, and thus it become an 'ought' for the individual.
  In addition, from empirical evidence the above experiences are common within the majority.

Note this point I highlighted earlier;

His method in that work differs from that of the Treatise: instead of explicating the nature of virtue and vice and our knowledge of them in terms of underlying features of the human mind,
he proposes to collect all the traits we know from common sense to be virtues and vices,
observe what those in each group have in common,
and from that observation discover the “foundation of ethics.”
(EPM 1.10).

The foundations of ethics are thus oughts that are shared by the collective* as justified from empirical evidences and philosophical reasonings. Hume also mentioned society, the collective, humanity and the human species in his works.
Hume did not mention 'ought' but he stated there is an imperative to act morally by the individual, thus an 'ought'.

The above is the general theme of Hume's morality.
Hume was very critical of theistic morality which simply make the connect of the relationship between the empirical and reason without justifications.
There are loads of diverse points within the Treatise and Enquiry - no time to discuss them less you dig into them to counter my views above.

My personal view is Hume's presented various disjointed elements and principles of morality, thus is not systematic nor sufficiently complete in contrast to Kant's systematic System of Morality/Ethics.

Suggest you reread Hume's Treatise [re Morality] and the Enquiry line by line which I had done.

[Veritas Aequitas]

The is/ought objection simply stated that just because a thing is the case does not mean we ought to follow a particular course of action.

The is nothing intrinsically different about Christianity, except that they use this line of argument to justify a morally objective position. The reason for this is that since god is the author of nature as well as the supposed author of the Book, then any observations of fact that can be leveled to support a moral line of prescription can be taken from facts. In effect god has designed the world such that moralists who believe are to be relied on simply to reveal the absolute and objective moral truths.
This is/ought problem is a recognition that "IS" is not enough, no matter that is a Christian observation or no.

A moral injunction has to be justified on other grounds, such as the consequence, the mitigations of circumstance and the utility of that moral choice. This does not qualify it as objective, but relative and subjective. Simply it depends.

For example just because slavery "IS" evil (let's imagine that you could prove such a thing), it would not automatically be a license to universal manumission and let slaves be forced to immediately find their own way to face death and poverty.
Just because smoking is harmful does not mean you can ban people from smoking.
Between the harm of smoking and the proscription of it there exists a whole host of factors both rational and emotional that are not so easy to unpack.

You claimed to be an old-fart on Hume's Principles of Morals but your above points re is-ought are not in alignment with Hume's intended thoughts as expressed in his Treatise and Enquiry.

Not my words at all.

The points in blue above are not your words??

I suggest you read or reread Hume's Treatise [sections related to morality] and Enquiry and you will realize all your points in blue above are not in alignment with Hume's views related to his is-ought and Principles of Morality.

[Sculptor]

You claimed to be an old-fart on Hume's Principles of Morals but your above points re is-ought are not in alignment with Hume's intended thoughts as expressed in his Treatise and Enquiry.

Not my words at all.

The points in blue above are not your words??

I suggest you read or reread Hume's Treatise [sections related to morality] and Enquiry and you will realize all your points in blue above are not in alignment with Hume's views related to his is-ought and Principles of Morality.

They are my words not Hume's. Now run along.

[Veritas Aequitas]

Not my words at all.

The points in blue above are not your words??

I suggest you read or reread Hume's Treatise [sections related to morality] and Enquiry and you will realize all your points in blue above are not in alignment with Hume's views related to his is-ought and Principles of Morality.

They are my words not Hume's. Now run along.

That was what I meant;

You claimed to be an old-fart expert on Hume's Principles of Morals but your above points [in blue] are not in alignment with Hume's intended thoughts [on is-ought] as expressed in his Treatise and Enquiry.

I have provided my reasons why you are off from Hume's Principles of Moral.
Any defense from you?