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 ...

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 ...