The important practical results (e.g. many particular drugs) that we get and need are obtained not because of understanding <i>why</i> they work but despite that, empirical testing is a key part of current process.<p>We have considered and discarded a <i>lot</i> of candidate drugs with great potential before starting human testing. As a rule, if some molecule would cure an important disease but for whatever reason doesn&#x27;t work on the popular strains of mice, then our current process would cause us to discard it.