Hume’s guillotine

In one of his books, the philosopher David Hume explains that all religions state what “is” (whether God exists or not, the nature of man, etc) and then what “ought” to be (morality). But Hume asks, can we really derive an “ought” from an “is,” and if so how can it be explained logically? This famous query has since become known as the is-ought problem or Hume’s guillotine, and it is one of the central questions of ethical theory and meta-ethics. Because of its importance, I would like to talk about it today.

Hume himself thought that it is impossible to logically derive an “ought” from an “is.” Because of this, says Hume, there can be no moral knowledge of any kind. From this we can derive two moral theories: moral skepticism and non-cognitivism. The former, as its name implies, is the idea that moral beliefs are unknowable. The latter holds that moral statements are neither true nor false. Both make it impossible to derive any system of morality, and for this reason Hume believes that no objective morality can exist. 

But not everyone agrees, and many critics have given what they consider to be answer to the question or pointed out problems in the theory. I would like to discuss some of these as well:

John Searle, who I have talked about at length in my posts about the Turing Test and the Chinese Room, explains in a paper that the inherent nature of a thing can describe its purpose if this purpose is included in the definition. Many philosophers side with Searle, stating that there is no reason the “ought” cannot be described as part of the “is.”

Ayn Rand, who I have also spoken about previously, dismissed the problem entirely. She stated that an “objective” theory of morals is necessary therefore must exist. Man’s purpose, according to Miss Rand, is the rational pursuit of one’s self interest; this is the greatest form of Objectivist morality. To me, her logic seems a bit sketchy, but this is not really the purpose of today’s post, so I’ll move on.

The third and perhaps most important criticism comes from naturalism. Like Searle, naturalists see no problem with deriving an “ought” from an “is,” and they believe that “oughts” are necessary when describing beings in terms of their goals. For example: “A ought to do B to achieve C” makes B the morality. Also, naturalists hold that moral rules descend from evolutionary truths, such as monogamy from pair-bonding. Thus, morals are an extension of the instinct to survive.

What do I think? I am inclined to agree with Searle and the naturalists. In terms of some religions Hume is correct, but he is certainly not right in every case. Morals are indeed an extension of our survival instinct, or at least our ability to adapt to them is. However, the naturalists would have us believe that morals are always “efficient” because of this, but since human nature is so mutable I think this is not always true.  

What does this mean for us? Very little. It simply shows that we are very far from developing a concrete theory of morals. Of course, this should be no surprise, since we have not worked out a concrete theory of metaphysics or epistemology either. However, the is-ought problem is something to keep in mind when examining a religion or belief system, and even though I disagree with Hume’s conclusion I must admit he has created an interesting philosophical tool.