Is–ought problem
The is–ought problem, as articulated by the Scottish philosopher and historian David Hume, arises when one makes claims about what ought to be that are based solely on statements about what is. Hume found that there seems to be a significant difference between positive (or descriptive) statements (about what is) and prescriptive or normative statements (about what ought to be), and that it is not obvious how one can coherently transition from descriptive statements to prescriptive ones. Hume's law or Hume's guillotine[1] is the thesis that an ethical or judgmental conclusion cannot be inferred from purely descriptive factual statements.[2]
A similar view is defended by G. E. Moore's open-question argument, intended to refute any identification of moral properties with natural properties. Ethical naturalists don't deem this so-called naturalistic fallacy a fallacy.
The is–ought problem is closely related to the fact–value distinction in epistemology. Though the terms are often used interchangeably, academic discourse concerning the latter may encompass aesthetics in addition to ethics.
Implications[edit]
The apparent gap between "is" statements and "ought" statements, when combined with Hume's fork, renders "ought" statements of dubious validity. Hume's fork is the idea that all items of knowledge are based either on logic and definitions, or else on observation. If the is–ought problem holds, then "ought" statements do not seem to be known in either of these two ways, and it would seem that there can be no moral knowledge. Moral skepticism and non-cognitivism work with such conclusions.
Responses[edit]
Oughts and goals[edit]
Ethical naturalists contend that moral truths exist, and that their truth value relates to facts about physical reality. Many modern naturalistic philosophers see no impenetrable barrier in deriving "ought" from "is", believing it can be done whenever we analyze goal-directed behavior. They suggest that a statement of the form "In order for agent A to achieve goal B, A reasonably ought to do C" exhibits no category error and may be factually verified or refuted. "Oughts" exist, then, in light of the existence of goals. A counterargument to this response is that it merely pushes back the "ought" to the subjectively valued "goal" and thus provides no fundamentally objective basis to one's goals which, consequentially, provides no basis of distinguishing moral value of fundamentally different goals. A dialectical naturalist response to this objection is that although it is true that individual goals have a degree of subjectivity, the process through which the existence of goals is made possible is not subjective—that is, the advent of organisms capable of subjectivity, having occurred through the objective process of evolution. This dialectical approach goes further to state that subjectivity should be conceptualized as objectivity at its highest point, having been the result of an unfolding developmental process.
This is similar to work done by the moral philosopher Alasdair MacIntyre, who attempts to show that because ethical language developed in the West in the context of a belief in a human telos—an end or goal—our inherited moral language, including terms such as good and bad, have functioned, and function, to evaluate the way in which certain behaviors facilitate the achievement of that telos. In an evaluative capacity, therefore, good and bad carry moral weight without committing a category error. For instance, a pair of scissors that cannot easily cut through paper can legitimately be called bad since it cannot fulfill its purpose effectively. Likewise, if a person is understood as having a particular purpose, then behaviour can be evaluated as good or bad in reference to that purpose. In plainer words, a person is acting good when that person fulfills that person's purpose.[8]
Even if the concept of an "ought" is meaningful, this need not involve morality. This is because some goals may be morally neutral, or (if they exist) against what is moral. A poisoner might realize his victim has not died and say, for example, "I ought to have used more poison," since his goal is to murder. The next challenge of a moral realist is thus to explain what is meant by a "moral ought".[9]