Scientific explanations arc subject to the occurrence of inconsistencies. To rule them out in many cases demands the construction
of new theories. As the examples of complementary explanations show, that may take a while. Furthermore, even if possible
in principle, it is not always reasonable to eliminate inconsistencies immediately, e.g., by bringing in a more sophisticated
formal language. After all, under some circumstances a provisional, not fully coherent explanation may be better than none.
In any case, we need a logically controlled approach to such inconsistencies. Modern logic provides the tools which are necessary
to solve this task. We will mention two alternative approaches.
This revised version was published online in June 2006 with corrections to the Cover Date.