&gt;&gt; One that needs supporting evidence and a proposed mechanism before it can be taken seriously.<p>IMHO it only needs supporting evidence - good solid evidence. A proposed mechanism is nice but is it really necessary? Do they really know how aspirin works? If so, did they prior to widespread use? Does anyone have a mechanism for quantum physics? Did Kepler have a mechanism for planetary motion?<p>I think a lot of science is actually people looking for the mechanism to explain accepted phenomena.