Peter Drucker is probably one of the greatest thinkers in management sciences over the last century.  I don’t know if he ever explicitly wrote or spoke about complexity, but the man obviously “got it”.  Consider what he wrote about “fact-based” decision making.

“Most books on decision-making tell the reader: First find the facts. But executives who make effective decisions know that one does not start with facts. One starts with opinions…The understanding that underlies the right decision grows out of […]