C.A.R. Hoare on simplicity
I coworker of mine is currently reading J2EE Development without EJB, and today he pointed out a couple of very nice quotes from C.A.R. Hoare that are included in a chapter entitled “The Simplicity Dividend”. The quotes are from Hoare’s speech at the 1980 ACM Annual Conference, where he was presented with the ACM Turing Award for that year.
In the first quote, Hoare relates his reaction to a specification for a new version of ALGOL in 1965:
I gave desperate warnings against the obscurity, the complexity, and overambition of the new design, but my warnings went unheeded. I conclude that there are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies and the other way is to make it so complicated that there are no obvious deficiencies.
The first method is far more difficult. It demands the same skill, devotion, insight, and even inspiration as the discovery of the simple physical laws which underlie the complex phenomena of nature. It also requires a willingness to accept objectives which are limited by physical, logical, and technological constraints, and to accept a compromise when conflicting objectives cannot be met.
In the second quote, Hoare gives his opinion on the lengthy project that eventually produced the PL/I programming language:
At first I hoped that such a technically unsound project would collapse but I soon realized it was doomed to success. Almost anything in software can be implemented, sold, and even used given enough determination. There is nothing a mere scientist can say that will stand against the flood of a hundred million dollars. But there is one quality that cannot be purchased in this way–and that is reliability. The price of reliability is the pursuit of the utmost simplicity. It is a price which the very rich find most hard to pay.
And one last quote, not included in the book, shows that even a career as stellar as Hoare’s had its share of failures:
There was no escape: The entire Elliott 503 Mark II software project had to be abandoned, and with it, over thirty man-years of programming effort, equivalent to nearly one man’s active working life, and I was responsible, both as designer and as manager, for wasting it.
This project spanned several years in the mid-60s. Hoare was doing commercial software development in the days before it was widely appreciated just how challenging software can be, and the whole speech is well worth reading to get the flavor of those times.
