We ask the rhetorical question:
Can we conceive of a software platform where a program P can be installed so that it performs as the program writer intended, without depending on the correctness and benevolence of other programs on the platform, even viruses, except where and how P chooses to rely on those other programs?
Commercial platforms all fail at this simple goal.
I claim that capability discipline in the platform design is uniquely suited to achieve this simple goal.
This is an empirical judgement arrived at after looking at architectures of a number of software platforms.
It is not about all conceivable disciplines.
(Is that all?)