The Free On-line Dictionary of Computing (30 December 2018):
"Complexity increases the possibility of failure;
a twin-engine aeroplane has twice as many engine problems as a
By analogy, in both software and electronics, the implication
is that simplicity increases robustness and that the right way
to build reliable systems is to put all your eggs in one
basket, after making sure that you've built a really *good*
While simplicity is a useful design goal, and twin-engine
aeroplanes do have twice as many engine problems, the analogy
is almost entirely bogus. Commercial passenger aircraft are
required to have at least two engines (on different wings or
nacelles) so that the aeroplane can land safely if one engine
fails. As Albert Einstein said, "Everything should be made as
simple as possible, but not simpler".
See also KISS Principle.