The Fact-Value Distinction
The fact-value distinction draws a line between statements about how the world is and judgments about how it ought to be. This distinction sits at the heart of moral philosophy because it raises a tough question: can we ever get from objective facts to moral conclusions? The answer you give shapes your entire approach to ethics.
Descriptive vs. Evaluative Claims
Understanding this distinction starts with recognizing two different types of claims.
Descriptive claims aim to report facts about the world. They can be checked against evidence and determined to be true or false. "The Earth is approximately 93 million miles from the Sun" is descriptive. You can measure it, verify it, and settle disagreements about it with data.
Evaluative claims (also called value judgments) express opinions, attitudes, or beliefs about the worth, goodness, or desirability of something. "Lying is morally wrong" is evaluative. You can't point a telescope at it or run a lab experiment to prove it true or false. It involves a judgment that goes beyond what empirical observation alone can settle.
The fact-value distinction is the idea that these two types of claims are fundamentally different, and that you can't simply move from one to the other without some extra step.
Hume's Is-Ought Problem
David Hume identified what's often called the is-ought problem (or "Hume's guillotine"). He noticed that writers on morality would start by describing how things are and then suddenly shift to claims about how things ought to be, without explaining how they made that jump.
His core argument: you cannot logically derive an "ought" statement from an "is" statement without introducing additional premises that themselves contain value judgments. For example:
- Fact: Donating to charity reduces suffering.
- Conclusion: You ought to donate to charity.
That conclusion feels natural, but it only follows if you add a hidden value premise like "reducing suffering is good." The factual claim alone doesn't get you there. This logical gap suggests that moral reasoning requires something beyond empirical observation and deduction. If "ought" statements can't be derived from "is" statements alone, the basis for moral claims needs further justification.
Moore's Naturalistic Fallacy
G.E. Moore raised a related but distinct challenge. He argued that it's a mistake to define moral properties (like "good") in terms of natural properties (like pleasure, happiness, or evolutionary fitness). He called this the naturalistic fallacy.
For example, a utilitarian might say "good" simply means "what maximizes happiness." Moore's response was his open question argument: even after you establish that something maximizes happiness, it still makes sense to ask, "But is maximizing happiness actually good?" The fact that this question remains open suggests "good" hasn't really been captured by the natural definition.
Moore concluded that moral properties are sui generis, meaning they're unique and can't be reduced to or fully explained by non-moral, natural properties. This challenges any attempt to ground ethics entirely in empirical science.
Arguments For and Against the Distinction
Arguments supporting the distinction:
- Hume's is-ought problem reveals a genuine logical gap between factual premises and moral conclusions.
- Moore's naturalistic fallacy suggests moral concepts resist reduction to natural properties.
- The apparent impossibility of settling moral disagreements through observation alone (the way you'd settle a factual dispute) supports treating facts and values as different in kind.
Arguments challenging the distinction:
- Moral realists hold that objective moral truths exist. If "torture is wrong" is objectively true, it starts to look more like a fact than a mere subjective preference, blurring the line.
- Some philosophers argue facts and values are inextricably linked in practice. Describing a situation as "cruel" or "unfair" already weaves together observation and evaluation.
- Pragmatists and certain naturalists contend the distinction isn't absolute. Values can be informed and constrained by facts, even if they aren't strictly derived from them.
This debate remains active in contemporary philosophy and has real consequences for how we think about the foundations of any ethical theory.
Moral Non-Cognitivist Perspectives
Moral non-cognitivism is the view that moral statements don't express factual propositions at all, which means they can't be true or false in the way descriptive claims can. Two major versions:
- Emotivism (associated with A.J. Ayer and C.L. Stevenson): Saying "stealing is wrong" is really just expressing a negative emotional attitude toward stealing, something like "Stealing? Boo!" It's not reporting a fact; it's venting a feeling.
- Prescriptivism (associated with R.M. Hare): Moral statements function as commands or prescriptions. "Stealing is wrong" means something closer to "Don't steal." Again, not a factual claim.
Both of these views reinforce the fact-value distinction by denying that moral language operates in the same way factual language does.
Moral relativism adds another layer of complexity. If moral truths are relative to a culture or individual, then values aren't just different from facts; they vary in ways that facts typically don't. This further complicates any attempt to treat moral claims as straightforwardly objective.