Whenever I point out that a very common thread of "thought"—if you can call it "thought"—in alternative medicine is nothing more than germ theory denialism, the usual reaction is incredulity. Newbies who haven't encountered quacks before invariably do a double take when I inform them that germ theory denialism is a thing, particularly among antivaccine activists. (After all, vaccines don't make sense if microorganisms don't cause disease.) Yet, time and time again I find examples of quacks who deny that disease is a consequence of infection. In fact, some go so far as to try to argue in the…