On Diversity, and the Elusiveness of Independence

Diversity, as a means of avoiding mistakes, is ubiquitous in human affairs. Whenever we invite someone else to check our work, we are taking advantage of the fact that they are different from us. In particular, we expect that their different outlook may allow them to see problems that we have missed. In this talk I shall look at the uses of diversity in systems dependability engineering.In contrast to diversity, redundancy has been used in engineering from time immemorial to obtain dependability. Mathematical theories of reliability involving redundancy of components go back over half a century. But redundancy and diversity are not the same thing.