One of the most common mistakes in moral debates is the assumption that a description of the world can yield a conclusion about how it ought to be.
A camera can record a murder in perfect resolution. It will capture the knife, the blood, the movement of the hand, and the moment the heart stops beating.
But in no pixel will it capture the fact that this is “wrong”.
We can add more cameras, measure the force exerted, map every neuron in the murderer’s brain, and reconstruct the chain of events down to the last detail. We will get an increasingly precise description of what happened.
We still will not find “must not” there.
David Hume observed that philosophers begin by talking about what is, and then, almost without explaining the transition, begin talking about what ought to be.[1]
But these are two different kinds of claims.
In nature, there is fierce competition for resources. It does not follow that human society ought to be cruel. Hierarchies appear again and again in human societies. It does not follow that existing hierarchies are just. We age, fall ill, and die entirely naturally. No one concludes from this that medicine is wrong because it interferes with the natural course of things.
And yet the leap keeps recurring: “This is how human beings have always behaved,” “This is how nature works,” “It’s part of evolution,” “It’s like this in every society.”
Perhaps. So what?
Suppose someone says: “The strong survive in nature, so society ought to reward the strong.”
The conclusion sounds as though it came from the fact, but it did not. Another claim was smuggled in along the way:
Society ought to imitate nature’s mechanisms of selection.
Now the argument has at least revealed itself. And the problem has shifted: why ought society to imitate nature?
An answer is possible, of course. But every answer will once again have to explain why the value it rests on is binding on us. The word “natural” solves nothing; parasites are natural. Cancer is natural. Earthquakes are natural. “Natural” tells us where something came from or how it works. It does not tell us whether we should want it.
Nor does “good” stand on its own. Good for whom? By what standard? Something can be good for a parasite and bad for its host, good for the individual and bad for society, good today and destructive twenty years from now.
Facts are still very important. If we have decided that we want to reduce suffering, science can help us discover what reduces it. If we want to prolong life, it can discover what prolongs it. If we have chosen a goal, facts can help us find the way to it.
But notice what happened in those sentences:
“If we have decided.”
“If we want.”
“If we have chosen a goal.”
Science enters after the goal is already on the table. And that leaves a much harder question than the one we began with.
If no pile of facts contains an “ought” – where does the validity of the value that allows us to say that anything ought to be come from in the first place?
Hume exposed the problem, but he did not solve that problem.
Sources
[1] David Hume, A Treatise of Human Nature, 1739–1740, Book III, Part I, Section I.
