Cranks are an occupational hazard that every scientist eventually faces. Fortunately, these characters are usually easy to spot. If someone claims to have a grand theory that overturns centuries of scientific knowledge--especially when the theory spans unrelated fields like physics and biology and economics--the odds are good that he or she is a crank. If the author publishes not in a standard scientific journal but in a book for general readers, watch out. And if the book is issued by the author rather than a conventional publisher, the case is pretty much airtight.
Unless, that is, the author is Stephen Wolfram....