How Do You Build a Science of the Whole Universe?

Imagine you’re trying to figure out the rules of a game, but you can only see a tiny corner of the board. You can’t see most of the pieces. You don’t know how many players there are. You aren’t even sure what counts as a move. That is the situation cosmologists found themselves in during the 1930s and 1940s, when they first tried to turn the study of the entire universe into a real science.

The problem was this: normal science works by doing experiments. You mix chemicals, you measure results, you form a theory, you test it. But you cannot experiment on the universe. You cannot make another universe to compare. You cannot change one thing and see what happens. All you can do is look.

So a furious debate broke out. It wasn’t just about which theory of the universe was right. It was about something more basic: what counts as a good way to do science when your subject is the whole of everything?

Two Ways of Thinking

Two very different kinds of scientists got involved in this debate, and they disagreed about almost everything.

On one side were people like Herbert Dingle, an astrophysicist who believed in what he called the “true scientific method.” For Dingle, science had to start with observations—real things you could see, measure, touch. You looked at the data. You noticed patterns. Then, and only then, you formed a hypothesis. This is called induction: you go from many specific observations to a general rule. Dingle thought this was the only honest way to do science. Anything else was just making things up.

On the other side was a brilliant and stubborn Oxford physicist named E. A. Milne. Milne thought Dingle had it exactly backwards. According to Milne, you could start with a good idea—a hypothesis—and then work out what consequences would follow from it. If those consequences matched what you saw in the sky, great. If not, you threw the hypothesis away. This is called hypothetico-deductivism: you start with a guess, then deduce what you should observe if the guess were true.

Milne went further. He thought the best hypotheses weren’t random guesses. They should come from very general principles about how the universe ought to behave. He proposed something he called the “cosmological principle”: the idea that every observer in the universe, no matter where they were, would see roughly the same thing. Not because it had been observed to be true—nobody had checked—but because it seemed like a reasonable starting point.

Dingle was horrified. To him, this was like deciding what the game rules are by closing your eyes and imagining them. “The foundation of science,” he declared, “must be observation, not invention.”

The Big Fight

The argument exploded in 1937 when Dingle published an article called “Modern Aristotelianism.” The title was an insult: it compared Milne (and a few other scientists) to the ancient philosopher Aristotle, who had tried to figure out how the world worked just by thinking about it, without doing experiments. For Dingle, this was the worst thing you could call a scientist.

Dingle’s article was remarkably angry. He used phrases like “paralysis of reason,” “intoxication of the fancy,” and “Universe mania.” He accused Milne and others of betraying the scientific method. Their theories, he said, were “chimeras”—imaginary monsters—that had no connection to real data.

The leading science journal, Nature, decided to publish a special issue where sixteen prominent scientists could respond. Some sided with Dingle. One geologist argued that “without using induction, Milne could not order his life for a day.” Another suggested that Milne was behaving like a poet, not a scientist.

But Milne had defenders too. A young cosmologist named William McCrea made the clearest argument: theories should be judged by whether their predictions match observations, not by how you arrived at them. If Milne had a new idea about how the universe worked, you should check whether his predictions came true. Complaining about his method was missing the point.

Why This Mattered

This wasn’t just an abstract argument among academics. Cosmology was stuck. For decades, scientists had known about Einstein’s General Theory of Relativity, which described gravity as a curvature of space and time. But when they tried to apply it to the whole universe, they got only two possible models: one where the universe was packed densely with matter, and one where it was essentially empty. Neither matched what astronomers actually saw.

Then in 1929, the astronomer Edwin Hubble discovered that distant galaxies were moving away from us. The universe was expanding. Suddenly, new models became possible. But nobody had a clear method for deciding which model was right. Observations were extremely difficult. The data was scarce and unreliable. You couldn’t just do more experiments.

So the debate about method was really a debate about how to do science when you’re stuck. When you cannot get enough data to settle things by observation alone, what do you do?

Milne thought you should use your imagination and your reason. Come up with the most beautiful, simple, logical model you can. Then work out what it predicts. If the predictions hold up, your theory is good.

Dingle thought this was dangerous nonsense. Without data as the foundation, you were just making up stories.

The Surprising Outcome

Here’s the strange part: Milne’s methods won.

Not his specific theory—that turned out to be wrong in important ways. But his way of doing cosmology became the standard. Within a few years, other scientists started using Milne’s approach. They took his operationalist idea (define your concepts in terms of actual measurements you can make). They took his hypothetico-deductive method (start with hypotheses, deduce consequences). They even took his cosmological principle, though they modified it.

The most famous result came from a younger scientist named Hermann Bondi. In 1948, Bondi proposed a radical theory called the “steady state” universe. According to this theory, the universe had no beginning and no end. It had always looked roughly the same and always would. This directly contradicted the idea that the universe had started with a Big Bang—which most scientists already believed.

But Bondi didn’t claim his theory was true because he had lots of data. He claimed it was valuable because it made very clear, precise predictions that could be disproved. If you could find evidence that the universe had changed over time—“fossils” from an earlier era, he called them—then steady state theory would be finished.

This was a new twist. Bondi had added the ideas of philosopher Karl Popper, who argued that a theory is scientific only if it can in principle be proven false. Astrology fails this test because its predictions are too vague to be clearly wrong. But steady state theory passed: it predicted that there would be no cosmic fossils, no evidence of an evolving universe.

For nearly twenty years, the theory stood. Then in 1965, astronomers discovered the cosmic microwave background radiation—a faint glow left over from the early universe. It was exactly the kind of fossil evidence Bondi’s theory said couldn’t exist.

And Bondi, true to his word, gave up the theory.

What We Learned

So who was right—Dingle or Milne?

The answer is complicated. Dingle was right that science needs observation. You cannot just make up theories and call them true. But Milne was right that in a data-poor science like cosmology, you cannot wait for perfect observations before forming theories. You have to work with what you have, and sometimes that means starting with a good guess and seeing where it leads.

Today, scientists use both methods. They collect data. They form hypotheses. They test predictions. But the debate left a lasting lesson: there is no single “scientific method” that works for every problem. Different kinds of questions require different approaches. And sometimes, the question itself—“How should we study this?”—is the hardest question of all.

Cosmology is still young. It is still data-poor, though less than it used to be. And scientists still argue about how to interpret what they see. But they no longer argue about whether it’s okay to start with a hypothesis. That battle is over. Milne won.

Key Terms

Term	What it does in the debate
Induction	The method of starting with many observations and building up to a general rule. Dingle thought this was the only legitimate way to do science.
Hypothetico-deductivism	The method of starting with a hypothesis and working out what observations should follow. Milne championed this approach.
Cosmological principle	The assumption that every observer in the universe sees roughly the same thing. Milne used this as a starting point for his theory.
Operationalism	The idea that scientific concepts only count as real if you can define them in terms of actual measurement procedures. Milne used this to argue that “curved space” wasn’t real.
Falsification	The idea that a scientific theory must make predictions that could potentially be shown false. Bondi added this to Milne’s method.

Key People

E. A. Milne – An Oxford astrophysicist who proposed that cosmology should start with rational principles and deduce consequences. His methods changed how cosmology is done, even though his specific theory was wrong.
Herbert Dingle – An astrophysicist who fiercely defended the traditional view that science must start with observations. He thought Milne was betraying the scientific method.
Arthur Eddington – A famous astronomer who also attacked Milne, but for different reasons. He thought the theoretical entities of relativity (like curved space) were genuinely real, and Milne was wrong to dismiss them.
Hermann Bondi – A younger scientist who adopted Milne’s method and added Karl Popper’s idea of falsification to create the “steady state” theory of the universe.
William McCrea – A cosmologist who defended Milne’s methods and helped show that they were really just a natural extension of how science had always worked.

Things to Think About

Dingle said science’s foundation must be observation, not invention. But how do you know which observations to start with? Don’t you need some theory just to decide what to look at?
Milne believed in starting with very general rational principles—like the idea that the universe should look the same everywhere. But how do you know if a principle is “reasonable” before you’ve tested it? What makes some principles seem reasonable and others not?
Bondi said a theory is better if it can be more easily disproved. But if a theory is easy to disprove, it might be wrong. Is it really a virtue to make your theory more vulnerable? Or is that just increasing the chances you’ll be embarrassed?
Both sides in this debate agreed that observation matters. They just disagreed about when and how it should enter the process. Can you think of a situation in your own life where you had to form a theory or make a decision without enough information? How did you decide what to do?

Where This Shows Up

Science classes. When your teacher tells you to use the “scientific method,” they are probably describing a version of Dingle’s approach. But real scientists often work more like Milne—especially when studying things that are hard to experiment on.
Detective stories. A detective who starts with clues and builds a case is using induction. A detective who imagines a suspect and then looks for evidence is using hypothetico-deductivism. Good detectives use both.
Everyday reasoning. When you try to figure out why a friend is acting differently, you might start with a hypothesis (“Maybe they’re upset about something”) and then look for evidence that confirms or disconfirms it. That’s hypothetico-deductivism in action.
Modern astronomy. The search for dark matter and dark energy is still happening in a data-poor environment. Scientists constantly argue about how much to trust their theories versus how much to demand observational proof. The 1930s debate never really ended.