Skip to main content

What is Science? Philosophy Has Answers (sort of)

Homeopathy vs. modern medicine. Astrology vs. Astronomy. Intelligent design vs. evolutionary biology.

Debates between scientists and pseudoscience supporters have increasingly infiltrated the public domain. Intelligent design proponents want the theory to be taught as a science; homeopathy practitioners claim to cure illness with highly diluted ingredients despite contrary scientific findings; and astrologers make constellation-based predictions found in the back page of newspapers worldwide.

Most experts tend to agree on what areas constitute pseudoscience, such as the three listed above. But what criteria should we use to differentiate between science and pseudoscience or the broader category of non-science?

Called the demarcation problem, this question has kept philosophers and scientists busy for over a century. So what is science? What test can we apply to a theory to see if it's scientific? No one has unambiguously answered these questions, but philosophers of science have made some headway in the debate over the last 50 years.

One of the most influential thinkers on this topic was the 20th century philosopher Karl Popper. He thought that the defining characteristic of science was falsifiability -- the ability to generate hypotheses that could be proven false by observations or experiments. So why did Popper chose falsifiability as the distinguishing factor between science and non-science? That answer lies in his thoughts on the theories of two famous 20th century thinkers: Albert Einstein and Sigmund Freud.

Psychoanalysis vs. General Relativity

In Popper's mind, Freudian psychoanalysis was certainly not scientific. Because psychoanalysis tried to explain all of human behavior, Freud's theory never presented claims that could be proven wrong. The primary goal and supposed strength of Freud's enterprise made it unscientific, according to Popper.

Einstein, however, made some "risky" predictions with general relativity. For instance, special relativity predicted that starlight would bend around massive objects, a hypothesis that astronomer Arthur Eddington tested during a 1919 solar eclipse as seen in the image to the left. The observations agreed with the hypothesis, and Einstein's theory passed a test. This is science -- at least to Popper.

Popper certainly didn't think that tests like these proved the truth of a theory, however. Instead, he thought that risky predictions that passed a test, such as Einstein's light bending hypothesis, only corroborated scientific theories. He thought that we could never truly verify a scientific theory, so the aim of science is to constantly try to refute theories with risky tests.

But Popper's thoughts on the topic didn't settle the demarcation problem. For instance, some have argued that astrology can make some falsifiable claims (that turned out to be false), and Popper would have to classify it as a scientific theory, albeit false one.

In fact, his work influenced a great deal of philosophers who later disagreed with him. Perhaps the most famous contributor after Popper was Thomas Kuhn, a philosopher who coined the modern day usage of the word paradigm.

Paradigms and Revolutions

Kuhn was fascinated with scientific revolutions. Einstein's radical transformation of modern physics was one such example of a revolution. But this wasn't what science is all about, according to Kuhn. Instead, it's mostly about day-to-day problem solving.

Einstein disrupted the paradigm of physics, moving from a Newtonian set of assumptions to those set out by his theories of relativity. Now, scientists had a whole new set of tools. After Einstein, many scientists set out on a new cycle of what Kuhn called "normal science."

When conducting normal science, scientists accept a set of shared theoretical beliefs, such as the theories of relativity, and solve all of the remaining puzzles that fall under these beliefs. Scientists solve these puzzles, and pseudoscientists do not.

Kuhn's solution remains controversial, however. Some have argued that conventional pseudoscience, such as astrology, may fall under the broad category of a puzzle solving activity. Other philosophers have built upon Kuhn's and Popper's work, but the demarcation problem remains an open topic of debate in philosophy.

Now What?

Philosophers have tried to find an adequate solution to the demarcation problem for years. They've made a lot of progress, yet they still haven't nailed down definite criteria that can separate science from pseudoscience or non-science. So why bother?

As pseudoscience creeps into many people's everyday lives, being able to distinguish between scientifically-backed results and pseudoscientific claims has become increasingly important. In philosophy of science, there's been definite headway toward articulating this distinction.

When people are afraid or distrustful of science, scientists need to appeal to outside help to convince skeptics of science's usefulness. And that's where philosophers can help. Philosophers are somewhat removed from the science, and they can deliver some perspective on what science truly is.

Falsifiability and problem solving may be two elements that help to define science, but we likely need more criteria. We're part way there, though, and scientists can use the work of these philosophers to convince non-experts why certain theories have much more justification than others.

For a more thorough explanation of the demarcation problem, check out the Stanford Encyclopedia of Philosophy's articles on Kuhn, Popper, and pseudoscience.

To keep up with Hyperspace, you can follow him on Twitter.


  1. "belief" as a synonym for "assumption" does not satisfy. Assumption has a relationship with drawing conclusions; belief has been hijacked by certaintists for their religious needs.

    So go ahead and use "assumption" three times in a row because it's the more appropriate word.

  2. What is Science?

    From the inception of imagination the very incidence of our intelligent mankind and from the very formula of imagination, there have been the expeditions of science viz. the start. With the improvement of imagination, the development of science is achieved and at the extremity of imaginative power came the idea that everything of the universe is dwelling on the sea of imagination.

    Encouraging the spirit of discovery and sharing of fundamental knowledge about the Universe and our place in its midst- at

  3. My thoughts? God has given you free will to make your own decisions. As for me, I admit there are things I don't understand. As a mortal, how could I understand everything? But these things will be explained to me after death. I have no doubts because I have seen miracles---things even nonbelievers called miracles. And we'll see how fast this post gets thumbs down


Post a Comment

Popular Posts

How 4,000 Physicists Gave a Vegas Casino its Worst Week Ever

What happens when several thousand distinguished physicists, researchers, and students descend on the nation’s gambling capital for a conference? The answer is "a bad week for the casino"—but you'd never guess why.

Ask a Physicist: Phone Flash Sharpie Shock!

Lexie and Xavier, from Orlando, FL want to know:
"What's going on in this video? Our science teacher claims that the pain comes from a small electrical shock, but we believe that this is due to the absorption of light. Please help us resolve this dispute!"

The Science of Ice Cream: Part One

Even though it's been a warm couple of months already, it's officially summer. A delicious, science-filled way to beat the heat? Making homemade ice cream.

Over at Physics@Home there's an easy recipe for homemade ice cream. But what kind of milk should you use to make ice cream? And do you really need to chill the ice cream base before making it? Why do ice cream recipes always call for salt on ice?