We don't know one millionth of one percent about anything. Any sufficiently advanced technology is indistinguishable from magic. Nothing motivates a man more than to see his boss putting in an honest day's work. Ater all is said and done, a heck of a lot more is said than done. A complex system that works is invariably found to have evolved from a simple system that works.
Computers are unreliable, but humans are even more unreliable.
Any system hich depends on human reliability is unreliable. Under the most rigorously controlled conditions of pressure, temperature, volume, humidity, and other variables the organism will do as it damn well pleases. Fill what's empty. Empty what's full. And scratch where it itches.