Unknowingly violating copyright is like unknowingly shoplifting; there are cases where you will have incorrect knowledge about licenses or somesuch (or you'll p

Unknowingly violating copyright is like unknowingly shoplifting; there are cases where you will have incorrect knowledge about licenses or somesuch (or you'll put a piece of fruit in your bag and not pay for it), but it's an extreme edge case. The problem with patents is that if you and someone else arrive at the same solution and the other person patents it before you put your solution out there, you are in violation of their parent. There is no such analogue for copyright. You and I can write functionally identical code for a decade and never once violate each other's copyright.