(Generative Adversarial Network)
In AI, a GAN is a dialectic; two systems that competitively cooperate to produce better results. The first system fakes reality and the second system compares the results against actual reality.
In philosophy, epistemology and metaphysics interact in a similar way. You can start with any metaphysics you want but if you can't show the epistemological basis for it, it can't be trusted. You can start with any epistemology you want but if it doesn't produce results that correspond to reality they'll be useless.
Metaphysics and epistemoloy are two sides of the same coin, yin-yang, not separate subjects. Neither can exist in a meaningful way without the other.