According to Hume, what can reason do?

(1) It judges relations of ideas through abstract reasoning.

(2) It judges relations of cause and effect through reasoning based on experience.

According to Hume, what can't reason do?

(1) "Reason alone can never be a motive to any action of the will"(458).

(2) Reason "can never oppose passion in the direction of the will"(458).

What is Hume's argument for (1)? Do you agree?

What is Hume's argument for (2)? Do you agree?

"Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them"(459).

According to Hume, there are only two (inexact) senses in which a passion can be called unreasonable:

(1) when founded on the supposition of the existence of objects that do not really exist;

(2) when means are chosen that are insufficient to the designed end.

But don't these examples show that reason can, at least, oppose the passions?

Hume's Moral Noncognitivism

Cognitivism with respect to a certain kind of discourse is the view that the discourse is propositional (and thus that statements in the discourse are true or false).

Non-Cognitivism with respect to a certain kind of discourse is the view that the discourse is not propositional (and thus that statements in the discourse are neither true nor false). Hume is generally regarded as a non-cognitivist.

Hume's main claim: Moral judgments are motivating. Reason is motivationally inert. Therefore, moral judgments cannot be the product of reason alone.

Hume's examples: the ungrateful sapling; incest; willful murder.

Hume's Argument Against the Metaphysical Version of the So-Called Naturalistic Fallacy

There is no way of deriving an ought (normative judgment) from an is (purely descriptive judgment) [without some premise connecting the two and there are no such premises that are true].

Millgram on Hume

Hume is generally regarded as an instrumentalist about practical reason—that is, that the only kind of practical reasoning is means-end reasoning.

[Is this the only kind of practical reasoning that Hume discusses? What about matters of existence?]

Millgram argues that this is a mistake. Hume should be understood as denying that there is any kind of practical reasoning at all. Hume is a skeptic about practical reason (or Practical Reason Anti-Realist).

What is Millgram's explanation of Hume's skepticism?

Hume's psychology allowed mental states to "have either [propositional] contents or motivational force, but not both"(84).

Hume the Practical Reason Skeptic [Anti-Realist]

"'Tis not contary to reason to prefer the destruction of the whole world to the scratching of my finger. 'Tis not contrary to reason for me to chuse my total ruin, to prevent the least uneasiness of an Indian or person wholly unknown to me. 'Tis as little contrary to reason to prefer even my own acknowledg'd lesser good to my greater, and have a more ardent affection for the former than the latter." (Treatise, quoted in Korsgaard)