SPIRAL NEBULtiE WIRTZ 145 



tions which agitate human thought and of formulating a sufficient 

 description of the genesis of the universe. It is yet too soon for our 

 perceptions, and their interpretations still contain contradictions. 

 But we may be sure that as long as contradictions exist our intelli- 

 gences and our imaginations will work for their solution. The con- 

 tradictions in our conceptions of the universe are the best guarantees 

 for the life of science and the future progress of knowledge. 



Only error is life. 



— F. Schiller — Cassandra. 



