I think, even today, a modern microprocessor is out of the reach of any single human to fully comprehend. This is definitely the case for the extremely vast field of computer science.
Maybe the future of computing and artificial intelligence are systems that are in our capability to build but beyond our understanding of why they do what they do!
I'll now go search for the previous discussion. The "past" link does not yield any results, and even searching for the TC URL does not find it.