No, but it helps. There are some very bright researchers who don't have one (Simon Peyton-Jones being one, for example), but they do help in forming people as s

No, but it helps. There are some very bright researchers who don't have one (Simon Peyton-Jones being one, for example), but they do help in forming people as scientists. Of course, working after getting your BSc. as a researcher on a specific area for many years is, in most aspects the same as doing a doctorate, so except for the lack of diploma, there probably shouldn't be a big difference.