How can biometrics detect the real from the fake?

10 years ago, this was a nightmare, because 10 years ago, face matching technology didn't work. The pose had to be absolutely right, the lighting had to be absolutely right. It was lethal if people smiled or had spectacles. The world is utterly transformed, and today a machine is tens of thousands times better than a human being at doing that task. So although it has required a lot of development and huge advances in machine learning technology, The problem of face matching is basically solved. And when people talk about biometrics, that's usually what they mean. But that is not the problem. The problem is this person looks exactly what they're supposed to look like, but are they real?