The mind has generated the number 2 out of emptiness. And so it goes on all the way up to 42, and maybe even beyond. Mind generates set containing empty set, which has one part. Mind generates set containing two parts, the set and the set containing the empty set. Numbers have causes - the algorithms that perform the operations on the sets.
Numbers have parts and aspects.
The number 1 is defined as the set which contains the empty set and so on. But in the final analysis the entire number system has been generated by the play of mind on emptiness, in the complete absence of the need to refer to any material thing, or things, which are being counted. Numbers are fundamentally devoid of self-existent inherent 'Platonic' existence. Mathematics arises out of mind and emptiness. Physics arises out of mathematics.