Each necessary, but only jointly sufficient
"for complex systems: there is no root cause.
Frankly, I think that this tendency to look for singular root causes also comes from how deeply entrenched modern science and engineering is with the tenets of reductionism. So I blame Newton and Descartes.
In the same way that you shouldnâ€™t ever have root cause 'human error', if you only have a single root cause, you havenâ€™t dug deep enough."