Insight itself is largely illusion - some semi-autonomous modules of the human mind are capable of quite sophisticated goal directed planning and behaviour even when consciousness is directing attention elsewhere (or even asleep!).
The output - the insight - is experienced as coming "out of nowhere" by the consciously accessible parts of the human mind. But this is not irreducibly different in kind from a computer CPU experiencing an interrupt from a co-processor with a calculation to deliver.
Cognitive psychology is an Alice-in-Wonderland rabbit hole sometimes! I blame Sci-Hub for making the research so accessible :-p