Where Science is out of its Depth

What the fact-value distinction tells us about what science can and cannot say

Science is just a project—it’s the project of making a model of nature. It’s such an important project that the world's most powerful nations devote a good chunk of their time and energy to working away at it. But what does it mean to produce a model of nature, and what exactly does this sort of model tell us?

We make models all the time. When an architect makes a cardboard model of a skyscraper, he can observe how the model reacts if he jiggles the table in order to try to predict how the real skyscraper would react if the earth beneath it began to quake. The better his model of the skyscraper, the more accurately he can predict the fate of his full-scale skyscraper during a seismic event.

Science tries to do the same sort of thing, just on the largest possible scale. Scientists plug away at research projects to try to improve our models of nature itself. The hope is that one day, we will have a model of nature that is so accurate, we can perfectly predict how things react to any possible manipulation. Right now, our model of physics is pretty good—scientists have mathematical models we can use to predict the motion of the heavenly bodies, the speed of a falling object, and solar eclipses down to the second. We can even predict how much time slows down next to a black hole.

Though our model of nature is really good at predicting certain phenomena, like those modelled by classical physics, we’re still embarrassingly bad at predicting other phenomena, like the weather. This doesn’t mean that we will never be able to predict the weather—all it means is that the model of nature we have right now isn’t complex enough yet. If we pour more time and energy into improving our model of nature, there’s nothing to stop us from eventually being able to predict the weather millennia into the future, the same way we can predict the position of the planets millennia into the future.

Hypothetically, once we’ve completed the project of science, the model of nature we end up with will give us total predictive power over nature. We could use this perfect model of nature to tell us exactly what we need to do to make anything we want a reality. Science, as it advances, presents us with a burgeoning menu of wonders we can perform— however, it says nothing about which wonders to perform.

David Hume, an 18th century Scottish philosopher, noticed something interesting about the statements we use to describe things in nature. He noticed that there’s no way of turning a statement describing the way something is into a statement about how a thing should be; at least not without injecting some information that isn’t already in the descriptive statement.

This brings us to the core of what science is and isn’t. Science is the attempt to produce a model of nature. A model of nature is just a description of nature, and since statements about value cannot be derived from descriptive statements, even though science gives us immense amounts of predictive power, it cannot tell us what goals we should use this power to pursue.

This means science is not a sufficient guide for action. Not even a perfect model of nature can tell us what we should do, it can only show us what’s possible.

Science is therefore incomplete—it guarantees us the ability to perform wonders, but it’s silent about what wonders we should perform. Refined models of nature can tell us how to build nuclear bombs, chemical weapons, antibiotics, and fertilizers. But the fruits of science only make us more powerful, not necessarily better. To determine what end goals we should pursue from among the options science presents us with, we have to strive to understand what makes a goal Good—and that means taking up the study of philosophy.