The co-author Scott Aaronson has a chapter in his lecture notes about that "suspect" subject which does a good job of motivating it: http://www.scottaaronson.co

The co-author Scott Aaronson has a chapter in his lecture notes about that "suspect" subject which does a good job of motivating it: http://www.scottaaronson.com/democritus/lec9.html http://www.scottaaronson.com/democritus/lec9.html His whole book on the subject "Quantum Computing Since Democritus" is excellent and worth a read.