> PhD is not strictly necessary, but the process and training that results in a PhD degree is. I was just about to post the same. I just finished a master's in

> PhD is not strictly necessary, but the process and training that results in a PhD degree is. I was just about to post the same. I just finished a master's in math (in fact, with additional coursework in physics and statistics I've almost completed two master's) and I don't feel ready to tackle outstanding math problems. And the PhD students I knew were receiving a lot of help from their mentors as they learned how to tackle outstanding problems. There's just so much to learn to contribute to research math these days, it's hard to imagine anyone learning it all on their own.