Other comments in this thread helpfully explain the context of these recommendations. The TEDx brand name is now used to label local events set up by busy volunteers who need criteria for evaluating speaking proposals. The majority of the criteria are sensible and helpful, but I see one criterion that is overly broad, as another subthread first noted.

"Holds a nonstandard degree. For instance, if the physics-related speaker has a degree in engineering, not physics; if the medical researcher does not have an M.D. or Ph.D.; if the affiliated university does not have a solid reputation. This is not snobbery; if a scientist truly wishes to make an advance in their chosen field, they’ll make an effort to engage with other scholars."

Well, unless what is meant here by "make an effort to engage with other scholars" is publish in the same peer-reviewed journals as the scholars with the expected credentials, this criterion sweeps up too many path-breaking scientists. I will give one famous example. James R. Flynn is a researcher on human intelligence who has had several peer-reviewed publications in Psychological Bulletin, the premier research journal on psychology in the United States.

http://scholar.google.com/scholar?q=author%3AJames+author%3A...

But Flynn's Ph.D. degree is in sociology, not in psychology. He looks at the discipline of psychology as an outsider, and it is precisely that outsider's view that helped him make a discovery missed by dozens of psychologists. He discovered that IQ scores have been rising in national populations all over the world during the last century, and that trend of rising raw scores on IQ tests is now called the "Flynn effect" in his honor.

Here is what the late psychologist Arthur Jensen said about Flynn back in the 1980s: "Now and then I am asked . . . who, in my opinion, are the most respectable critics of my position on the race-IQ issue? The name James R. Flynn is by far the first that comes to mind." Modgil, Sohan & Modgil, Celia (Eds.) (1987) Arthur Jensen: Concensus and Controversy New York: Falmer. Here's what Charles Murray (all right, not a psychologist nor a geneticist) says in his back cover blurb for Flynn's book What Is Intelligence?:

http://www.amazon.com/What-Intelligence-Beyond-Flynn-Effect/...

"This book is a gold mine of pointers to interesting work, much of which was new to me. All of us who wrestle with the extraordinarily difficult questions about intelligence that Flynn discusses are in his debt." As psychologist N. J. Mackintosh (1998, p. 104) writes about the data Flynn found: "the data are surprising, demolish some long-cherished beliefs, and raise a number of other interesting issues along the way." Flynn has earned the respect and praise of any honest researcher who takes time to read the primary source literature. Robert Sternberg, Ian Deary, Stephen Pinker, Stephen Ceci, Sir Michael Rutter, and plenty of other eminent psychologists recommend Flynn's research. So, yes, sometimes "an effort to engage with other scholars" will happen after a scholar has already earned his last academic degree, and a scholar that has an important concept named after himself by people who have the standard degree will never have the standard degree for the field in which he made his mark.

EDIT PROMPTED BY SECOND REPLY: I'll attempt to be clear here. If the TEDx criteria included "has never been published in any major journal related to their chosen field" rather than "holds a nonstandard degree" not related to their chosen field (to speak about), I might have fully agreed with the criteria from the get-go. But degrees are both an overinclusive criterion and an underinclusive criterion. In other words, using degrees as a criterion for vetting speakers lacks both sensitivity and specificity.

http://en.wikipedia.org/wiki/Sensitivity_and_specificity

Instead, look at publications as the relevant criterion. A person who has peer-reviewed publications in a good-quality medical journal is competent to speak on the issues discussed in that person's publications, with or without a medical degree, while a person with the M.D. degree who has never published in anything but "alternative medicine" journals is not well qualified to speak about medicine. Publications matter more than degrees, as the example of James R. Flynn I gave in the original edit of this post shows.

On the broader "demarcation problem" of distinguishing science from pseudoscience, a really valuable recently published book is The Pseudoscience Wars: Immanuel Velikovsky and the Birth of the Modern Fringe by Michael D. Gordin,

http://www.amazon.com/dp/0226304426

which I found to be quite an interesting read, full of historical and ideological connections I had not heard about before. The author, a historian of science based at Princeton University, makes clear that demarcating between "science" and "pseudoscience" is not at all easy in any era. Reviewers generally like this book, as I did.

http://www.timeshighereducation.co.uk/story.asp?storycode=42...

http://www.tnr.com/book/review/pseudoscience-wars-michael-go...

http://online.wsj.com/article/SB1000087239639044470900457765...

http://www.lrb.co.uk/v34/n21/steven-shapin/catastrophism