People were explaining things fine with other systems (EG the olde four-element idea) untill we started looking through enourmous microscopes. So what's to say those other systems aren't TRUE for the parts of the world they represent (in this case the macroscopic universe)? What really defines the 'truth' anyway? Modern science is accepted as 'truth' because it describes all (or most) phenomina accurately. Einstein's theories of relativity are also accepted as 'truth', even though they only hold for non-quantum objects; only a limited number of phenomina. So might other, "disproved" or "outdated" theories also be 'true'? What actual reason is there to think they are false?