&gt;How do we choose which ones to teach?<p>Which one leads to a richer vein of further research?<p>Which one makes better predictions?<p>Which one finds more applications?<p>Diversity and scope can be important only so far as they improve the systems in terms of scientific validity.<p>Your arguments are exactly the ones used by creationists for the purpose of making that internally consistent system seem as valid as the theory of evolution.