We might think that telling the difference between science and pseudoscience is easy: science is based on empirical evidence, pseudoscience is not. But things are a lot more complicated than that. Coming up with a definition of either science or pseudoscience turns out to be incredibly hard. Instead of looking at the content of the theories to tell whether they count as science, an alternative is to focus on the people putting them forward, the care with which they approach their claims, and their character, writes Massimo Pigliucci.

What’s so difficult about separating sound science from pseudoscience? Let’s give it a try. Fundamental physics is, clearly, science. Homeopathy is, just as clearly, pseudoscience. Why? Well, because the first one is based on empirically well-established theories that make precise and reliable predictions about how the world works, while the second one is founded on notions that contradict basic chemistry and biology and has been demonstrated over and over not to work. Case closed, right?