Hume's argument for the subjectivity of morality

Question

I am trying to analyze the following argument by Hume in his Treatise of Human Nature:

But can there be any difficulty in proving, that vice and virtue are not matters of fact, whose existence we can infer by reason? Take any action allowed to be vicious: Wilful murder, for instance. Examine it in all lights, and see if you can find that matter of fact, or real existence, which you call vice. In which-ever way you take it, you find only certain passions, motives, volitions and thoughts. There is no other matter of fact in the case. The vice entirely escapes you, as long as you consider the object. You never can find it, till you turn your reflection into your own breast, and find a sentiment of disapprobation, which arises in you, towards this action. Here is a matter of fact; but it is the object of feeling, not of reason. It lies in yourself, not in the object. So that when you pronounce any action or character to be vicious, you mean nothing, but that from the constitution of your nature you have a feeling or sentiment of blame from the contemplation of it.

I am reconstructing it as:

• When examining willful murder, we find passions, motives, volitions and thoughts (in the murderer).
• This is an exhaustive list of the matter of facts of the crime.
• We did not find “vice” in the matter of facts of the crime.
• We find a sentiment of disapprobation towards the crime inside ourselves, as a matter of fact.
• That sentiment is a feeling, not reason.
• Conclusion: when we say that a murder is vicious, we express a subjective feeling.

However, it seems there is something slightly amiss about the term "vice" itself. It seems the argument actually defines vice in its conclusion (at least in my reconstruction), but that term was used in the third premise already, before being defined. How can we be sure we didn't find "vice" in the matters of fact of the crime, when in fact, what constitutes "vice" is defined later in the argument as a "sentiment of disapprobation"? Hume seems to use an implicit premise that we know how to recognize "vice" when we see it, or at least the absence of "vice" in the matters of fact of the murder, that we have at least some sort of shared intuition of what "vice" is (since we are not finding it). Hume seems to assume we can tell that there is no "vice", and furthermore that we will all agree on that. Should I add that hidden premise to my reconstruction to make the argument more cogent?

My question is really about 1) whether my reconstruction is right or misses that implicit premise about an immediate understanding of "vice"; 2) whether there is a logical defect in the argument, precisely because the term "vice" is used before being properly defined.

Answer 1

If Hume claims that the only vice is murder, then he can restrict the discussion to murder. However, if Hume is making a claim about vice in general, and Hume acknowledges that there are actions other than murder than are correctly classified as vices, then we are free to consider other examples of vices.

Consider the example of cheating in a sporting competition to win fame for the competitor, prize money, and national prestige for the country represented by the athlete. A coach who has been hired to help the national team cheat in the sporting competition may feel within himself or herself a feeling of disapproval arising within himself or herself if the cheating method is likely to be detected by the authorities, and to feel little or no disapproval if the cheating method is likely to escape detection. However, it doesn't follow that such an example of fraud is not a vice.

Perhaps a clearer example is available for the crime of perjury, and now we can return to the vice of murder creating the circumstances for perjury to be committed. Suppose that somebody is accused of murder, and the defendant is actually guilty, but chooses to testify under oath in court. The defendant chooses to lie, and the vice lies in the conflict between the truth and the testimony of the defendant. In contemplating what words to speak, the defendant is likely to feel revulsion at the thought of either disclosing the truth, or telling a lie that isn't effective in deceiving the jury. We cannot conclude from the revulsion of the defendant that the telling of the truth would be a vice for the defendant. The revulsion arises from contemplating the consequences of telling the truth.

We can also consider an example of a vice for which harm to the person who will be committing the vice is foreseeable as not merely possible, but inevitable. For example, consider driving in the wrong direction in a given lane of a highway at high speed. Do you find a sentiment of disapprobation, which arises in you, as you seriously imagine in the near future driving at high speed in the wrong direction in a given lane of a highway at high speed? Yes? And from that sentiment of disapprobation do we conclude that you have an unwarranted feeling, and that it is a mere feeling, with no reasonable basis?

If Hume is right, then a murderer, shortly before being released from prison, should be able announce that he is planning to commit another murder in the near future, and the prison authorities should provide a psychologist to help the murderer overcome any Hamlet-like indecisiveness or anxiety. After all, if there is no vice except in the feeling of a person contemplating vice, then the only problem is the anxiety, a neurotic condition that is to be relieved with assistance from clinical psychologists. The unfortunate period of imprisonment has encumbered the murderer with a hesitancy to commit another murder. What can be done to help him overcome that hesitancy, and proceed with wholehearted enthusiasm to commit another murder?