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I thank Cui Zizai — my old friend, former classmate, collaborator and interlocutor — for this opportunity to revisit Hume. Zizai sent me an email (one of his periodic circulars on mathematics, politics and philosophy) regarding his take on Hume, in particular the infamous line “reason is, and ought only to be the slave of the passions” in Hume’s A Treatise of Human Nature (“Treatise”).
Sent 1:28 am, 26 December 2020 (UTC+08:00) |
Zizai has two concerns which I shall attempt to address:
- Is the bipartite claim “reason is, and ought only to be the slave of the passions” is–ought fallacious?
- Does Hume offer an argument for his “ought” claim? How can it be justified?
Is the bipartite claim “reason is, and ought only to be the slave of the passions” is–ought fallacious?
Let us refer to Hume’s introduction of the is–ought problem (Treatise 3.1.1.27):
I cannot forbear adding to these reasonings an observation, which may, perhaps, be found of some importance. In every system of morality, which 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 an 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 shou'd be observ'd and explain'd; and at the same time that 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.
Hume observes that “is” is essentially different from “ought” and expresses scepticism of deducing “ought” statements from “is” statements. The is–ought fallacy is committed when an “is” statement is made to imply an “ought” statement. Hume suggests that a set of purely descriptive premises cannot entail a prescriptive conclusion.
Note that “reason is, and ought only to be the slave of the passions” is made up of two parts: “reason is the slave of the passions” and “reason ought only to be the slave of the passions”. As these two parts are independent of each other with no implication in between, it is not is–ought fallacious to say that “reason is, and ought only to be the slave of the passions”.
Does Hume offer an argument for his “ought” claim? How can it be justified?
Hume establishes that “reason is the slave of the passions” because reason cannot give rise to will and also, therefore, to action. Only the passions produce motivations — desired ends — and reason is left to work out the means to those ends. In other words, “reason is the slave of the passions” because reason can only be the slave of the passions. It is impossible for reason to be equal or superior to the passions. Any attempt to unshackle reason from its subordination to the passions is futile. Read this way, “reason ought only to be the slave of the passions” serves to put reason in its place and dissuade people from trying to salvage reason’s purported pre-eminence and fundamentality, for they are not obligated to or obligated to not do so. Textually, this is supported by the clause which follows: “and can never pretend to any other office than to serve and obey them”. This reading is supported by the “ought implies can” doctrine. After bringing in some modal logic (ignoring any deontic logic concerning degrees of “ought”), the implication diagram looks like this:
Visibly, as argued before, no is–ought fallacy is committed here, because the “ought” claim is not derived from any purely descriptive “is” claim, but rather a higher-order, modal “can” claim. But what if we treat Hume’s “ought” claim as independent and not stemming from the impossibility of reason being equal or superior to the passions? As an individual “ought” claim, does it hold? And if it does hold, why?
Since no prescriptive conclusion follows from descriptive premises, what is Hume’s “ought” claim based on? Zizai is correct to observe that Hume does not offer an argument for “reason ought only to be the slave of the passions”. I believe Hume would reply that no “ought” claims can be rationally justified, judging from what he writes in Treatise 3.1.1.6:
Since morals, therefore, have an influence on the actions and affections, it follows, that they cannot be deriv'd from reason; and that because reason alone, as we have already prov'd, can never have any such influence. Morals excite passions, and produce or prevent actions. Reason of itself is utterly impotent in this particular. The rules of morality, therefore, are not conclusions of our reason.
More concisely, in Treatise 3.1.2.1:
Morality, therefore, is more properly felt than judg'd of
To me, this suggests that Hume intends his “ought” claim to be a foundational belief born of feeling. In other words, it holds, and it holds because it’s a first belief which requires no justification.
Hume expounds more on the nature and origin of morals in the rest of the Treatise. Recognising that, at this juncture, many more hairs can be split and many more paths can be taken, I am happy to close and entertain any responses or excursions separately. ∎
Thank you Quince. I hope to meet you soon.
ReplyDelete1. Is there a difference BETWEEN the "ought" used in every system of morality AND the "ought" as in Reason ought not be anything other than a slave to the passions?
2. Did Hume *prove* that Reason cannot be anything other than a slave to the passions, or did he *define* Reason to be the mental process that takes place after observation and motivation?
3. Following Alex Rosenberg, how much are Hume's ethics and Hume's metaethics compatible?
I responded to you through Facebook on New Year’s Day; just posting the same content here.
DeleteHi Zizai! Thanks for your response.
1. Yes, I think there is. There may not be a difference in kind but there is at least a difference in degree. Analogously, “I ought not to stab others” and “I ought not to be late” are quite different, for it is more excusable to be late than to stab others.
2. I think this answers both questions: https://plato.stanford.edu/entries/hume/#MorRatCriPhaTre
3. Rosenberg writes: “Hume’s metaethics and his ethics are arguably inconsistent. He was a metaethical “noncognitivist”—ethical claims are not true or false but expressions of emotions. He was a substantive normative sentimentalist—ethical claims are right to the degree they reflect appropriate emotions. His substantive ethical theory is open to critique based on his metaethical theory.” Does “right” mean “true”? Even if it does, the varying “degree[s]” of rightness/truth oppose the cognitivist true/false binary. It is not difficult to imagine an act evoking different emotions of different intensities in different people. Likewise, it is not difficult to imagine an act and its opposite both evoking the same “appropriate” emotion in different people. It seems that ethical claims are not propositions which can be evaluated for truth or falsity. That said, Hume might be a sceptic but he wasn’t a relativist. Many things boil down to “custom”: we are somehow just wired to infer causation from banging billiard balls and show sympathy for fellow humans, among others. I think cognitivism can work for Hume only if truth is relaxed to be contextual or pragmatic.