Lawrence Krauss is quite right that we need to be much clearer about the role of falsifiability in making a theory “scientific” (3 December, p 23). Despite taking mostly science subjects at school and ...

Can a theory that isn’t completely testable still be useful to physics? What determines if an idea is legitimately scientific or not? This question has been debated by philosophers and historians of ...

Today, when an algorithm identifies a tumor in a tissue sample, it doesn't reveal how it arrived at this result. And that does not inspire trust. Researchers are therefore pursuing a new approach.

About 90 years ago, philosopher Karl Popper noticed that Freud’s theories explained everything. That may sound like a good thing. Who wouldn’t want such a powerful theory? But Popper argued that a ...