Either way it’s safe to the say the abstraction has failed and isn’t doing its job anymore if you have to know the implementation details. To use your garbage

Either way it’s safe to the say the abstraction has failed and isn’t doing its job anymore if you have to know the implementation details. To use your garbage collection example, regardless you consider it a leak or not, the result is the same, if you have to deep drive into the workings of the garbage collector and how it manages memory, the abstraction has failed to do its job: to free you from the burden of managing memory. His point is that all nontrivial abstraction breakdown at some point / under certain circumstances.