I remember a long discussion in an academic seminar in the mid-1970s, when the term "software crisis" was in full swing and the notion of correctness proofs of programs was put forward as a possible remedy. Professor C.A.R. [Tony] Hoare, the speaker at the seminar, had eloquently presented the principles and the advantages of correctness proofs replacing testing. After a long discussion about the pros and cons, Jim Morris got up and disarmingly asked: "But Tony, what is your answer if we frankly confess that we dearly love debugging? Do you want us to abandon our most cherished enjoyment?"