“If there isn’t a study supporting it, it cannot be true.” This position is a real mess, and it all breaks down to an argument from ignorance.
The basic problem is that people tend to believe things are either true or false, but that’s not really the only options. It is possible that we don’t know whether something is true or false (i.e. ignorance), and asserting that because something hasn’t been proven true it must be false is a terrible mistake. This is the same error as claiming that something hasn’t been disproven yet, so it must be false. If we don’t know whether something is true or false, then we simply don’t know.
I realize that anecdotal information cannot and should not sway standard public policy, but it should influence research on unresearched propositions, and people should not be forbidden from practicing or attempting to exploit the benefits that may or may not exist.
For a concrete example, most recently, there was a big to-do about “cupping” recently because of the Olympics. Cupping is a traditional Chinese medicine where suction is applied to the body for some health benefit, such as relieving pain from muscle cramps. Swimmers and other athletes at the games had visible circles on their bodies, which they claimed was part of a treatment for sore muscles. The proper response to this should have been “It is interesting that these athletes are claiming to have this experience. We should investigate to determine what is causing it.” It is a traditional practice, but there has been limited research with poor methods on the practice, which leaves us in ignorance on how it might work or what its limitations might be.
Instead, I am seeing enormous numbers of people claiming either that “It does not work because there is no evidence documenting that it does” or “If the athletes say it works, then it definitely works and we should take their word for it.” Neither of those two statements is healthy discussion. The first is a blatant argument from ignorance (as if humanity has already achieved perfect understanding of the world), and the second refuses to let us investigate the phenomenon in order to gain a better understanding. Whether the practice even provides a benefit is not well established yet. Some of the hypothesized explanations for the reported benefits of cupping suggest that it is pulling blood (and dissolved chemicals that cause soreness) to the surface of the skin, out of the muscle. Others have suggested that the suction pulls the muscle up like a massage, to provide relief that can’t be achieved manually since we can’t reach inside people. And of course there is the placebo effect, which provides benefits to things that have no statistical benefit.
Anecdotes are not strong evidence, but they do indicate directions that research should look. However, without good research on the topic, anecdote is all there is. Claiming that no research has been done to support an idea when no good research has been done at all does nothing but build a wall of ignorance around our existing knowledge, such that we could never learn anything new ever again. Scientific investigation requires both openness to new ideas and skepticism of those ideas to make sure they are true. Either one without the other to balance it will trap us in ignorance.