When we follow the way of the computer scientist, we treat defective software as processes that fail to manipulate symbols correctly. Computer science studies symbol manipulation by digital electronics. Some of the theoretical concepts of computer science for classifying and analyzing information can be applied to the process of debugging. Computer scientists advance their discipline by inventing layers of tools that can be composed into larger systems. When we follow the way of the computer scientist, we will also consider tools that can automatically diagnose software defects.