We have two sections titled “Moral Distinctions Not Derived from Reason” and “Moral Distinctions Derived From a Moral Sense.”
In the first, he argues that we do not use reason to distinguish between the morally good (or virtuous), morally evil (vicious), and morally indifferent. In the second, he maintains that these distinctions are a matter of how we feel when we think about someone’s character or actions.
The first section goes over some of the arguments we saw in the section on reason and the will in greater depth. It also covers some rather eccentric rationalist accounts of morality, where a “rationalist” account is one that maintains we use reason to know what morality requires. And it ends with some famous claims about the gap between “ought” and “is.”
The second section lays out the basic ideas of Hume’s own moral theory. It includes a celebrated discussion of the different senses of the term “natural,” in its discussion of whether morality is or is not natural.
This section is negative; it denies that we use reason to distinguish between good and bad.
For both sections, a little background on what Hume means by “perception,” “impression,” and “idea” will help. According to Hume, everything in your mind is a perception. There are two kinds of perceptions: impressions and ideas. Impressions are feelings while ideas are thoughts. Impressions can include the senses and emotions. Hume thinks that seeing something is a kind of feeling: the light from a lamp is felt in the mind. So when you see a lamp you have an impression and when you feel angry, you have an impression. Sometimes you think about things without having an impression of them. I am thinking about the sun now even though it has gone down. Hume calls my thought about the sun an idea and, he maintains, all ideas are copies of impressions. So I could not have any thoughts that are not derived from an impression, usually impressions from the senses.
After some throat clearing, Hume identifies the target of this section in the fourth paragraph. It is moral theories that hold that “virtue is nothing but a conformity to reason; that there are eternal fitnesses and unfitnesses of things, which are the same to every rational being that considers them; that the immutable measures of right and wrong impose an obligation, not only on human creatures, but also on the Deity himself” (3.1.1 par 4).
Having identified the target, we get down to business.
Reason cannot govern the will. Morality is supposed to govern our actions, but as he thinks he showed in 2.3.3, reason cannot govern our actions, therefore, morality is not derived from reason. Paragraphs 5-7.
Passions and actions are not representative (paragraphs 9-10). This repeats the argument from 2.3.3, par. 7. If passions do not represent anything, they cannot be true or false; there is nothing for them to be true or false about. One function of reason is to determine whether the way we represent reality is true or false. My belief that there is a pencil on the table does represent something, namely, the pencil. I can use reason to determine whether the evidence supports my belief or not: I can touch it and see if it feels like a pencil, and so on. (Note that this is what Hume calls “probabilistic” reasoning rather than “demonstrative” reasoning. These paragraphs are tricky.)
Objection: we can use reason to evaluate the causes or the effects of actions. Maybe that is where reason is relevant to morality (paragraph 11). Hume splits this into two branches: causes of actions and effects of actions.
Causes of actions (paragraphs 12-15). Beliefs (“judgements”) can cause actions and they can be true or false. Maybe this is where reason finds good and evil. I think there is a very sharp observation in the second half of paragraph 12 that applies to almost all rationalist accounts of ethics, and not just the ones Hume is talking about here.
Effects of actions (paragraph 16). This criticizes an eccentric theory that all immoral actions are lies. E.g. if I commit adultery, I implicitly tell the lie that the person I am amorously involved with is my spouse. We are not going to talk about this. The footnote is very funny, for what it is worth.
Conclusion: reason cannot distinguish between good and evil. Paragraph 17. We should be done: that was a conclusion! But wait, there is more!
We are going back to the distinction between reasoning about demonstrations and reasoning about probabilities (paragraph 18). Specifically, he is going to argue that demonstrative reasoning cannot yield moral conclusions (paragraphs 19-26) and then that probabilistic reasoning cannot do so (paragraphs 27-28). We are unlikely to talk about the first, but we will talk about the second, concerning probabilistic reasoning. So you can skip to paragraph 27 if you are finding this hard slogging.
Demonstrative reasoning. Demonstrative reasoning consists in comparing ideas on four dimensions: resemblance, contrariety, degrees in quality, and proportions in quantity or number (paragraph 20). Hume asserts, plausibly, that you cannot get from these relations to any conclusions about good or evil. Of course, his opponents probably mean something different by the words “reason” and “reasoning.” So he tries to establish two conditions that, he says, any system of moral demonstrations would have to meet. And then he gives reasons for doubting that they could be met. The conditions are in paragraphs 22 and 23. Then he adds a more general argument in paragraphs 25-26.
The first condition is that the two things to be related to one another are things that are internal to the mind, like motives, and things that are external to the mind, like what your body does. Hume does not think that demonstrative reasoning can ever discover anything outside of the mind; it is only concerned with the relations among ideas inside the mind. (paragraph 22)
The second condition is that the relevant relations have to govern the behavior of all rational beings, including God. But we have no understanding of what motivates God and so we can never establish this. (paragraph 23)
Finally, Hume gives a series of examples meant to show that moral distinctions cannot be based on relations among ideas. Plants and animals kill or have sex with their parents without being thought to do anything evil. When people do those things, by contrast, they are thought to be evil. Is the difference that people are rational and so capable of knowing that what they are doing is wrong? Hume thinks that this does not go anywhere. Reason is a way of knowing things. So all it could tell us is that a given course of action would involve killing or mating with our parents. If we just used reason, where would find the basis for adding “and that would be wrong”? (paragraphs 25-26)
Probabilistic reasoning. Look back up at number 4. We are on the second branch of the distinction now. And, thankfully, we are near the end. Probabilistic reasoning is reasoning about cause and effect. We take a bunch of observations about what went together with what in the past and try to infer what will happen in the future: every time a hammer hit a window, the window broke, so if I swing the hammer at this window, it will break. Hume expresses some reasonable doubts about the relevance of this kind of reasoning to morality.
He also goes way beyond that with some apparent claims about the meaning of moral language: “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” (paragraph 27). He adds an analogy with color. And he notes that none of this makes any practical difference, since people will still act as if their moral beliefs are true or false rather than products of their feelings. Those are all worth discussion.
Finally, we get the famous claim that there is a gap between “ought” and “is” in paragraph 28. Not talking about that would be like going to Paris and not seeing the Eiffel Tower.
This section is positive; it maintains that we use feelings to distinguish between good and bad.
Hume’s view is that morality “is more properly felt than judged of” (paragraph 1). Moral judgements like “she is a good person” or “that would be an evil thing to do” are feelings rather than the product of reasoning (paragraph 2). Consequently, the way to do moral philosophy is to “shew the principles which make us feel a satisfaction or uneasiness from the survey of any character in order to satisfy us why the character is laudable or blamable” (paragraph 3).
Note: it sure sounds as though the feelings here represent something. “We do not infer a character to be virtuous, because it pleases; but in feeling that it pleases after such a particular manner, we in effect feel that it is virtuous” (paragraph 3, italics added). That says the feeling represents the character as being virtuous. Compare point 2 in the outline of 3.1.1.
Objection: inanimate objects cause us to have feelings but they are not morally good or bad. Reply: the feelings that constitute moral judgments are feelings about “the character or sentiments of any particular person.” In particular, they are disinterested feelings: “it is only when a character is considered in general, without reference to our particular interest, that it causes such a feeling or sentiment as denominates it morally good or evil.” (paragraph 4)
Hume asserts that the disinterested feelings we get in response to people’s character feel different from the feelings we get from inanimate objects. That is not a terribly helpful way of answering the objection. But it does tell us something important about what his theory holds. It holds that moral judgements are disinterested feelings about people’s characters. That is what he is going to have to make good on.
A reference to Hume’s theory of the passions (paragraph 5). Hume thinks this helps in distinguishing the feelings that are relevant to morality from those that are not. I have to confess that I did not follow his reasoning.
Can there be a theory? Can we reduce the diversity of moral judgements to more basic categories? Hume thinks we can. He will have to show that, of course. (paragraph 6)
Is morality natural? It depends on what the word “natural” means. Hume goes over three possible meanings of “natural.” (a) The natural is opposed to the miraculous, (b) it is opposed to what is rare or unusual, and (c) it is opposed to what is artificial or created on purpose. The last one is the most important for Hume’s purposes. He is going to argue that parts of morality are artificial and other parts are natural, in the sense that is opposed to artificial. (paragraphs 7-9). He concludes by casting aspersions on the idea that morality is simply what is natural and vice is what is unnatural (paragraph 10).
The question that Hume’s moral philosophy will seek to answer: “Why any action or sentiment, upon the general view or survey, gives a certain satisfaction or uneasiness in order to shew the origin of its moral rectitude or depravity” (paragraph 11). He put it in italics, so you know it is important.