SECRET 1: Competence without Comprehension: Something—e.g., a register machine—can do perfect arithmetic without having to comprehend what it is doing. SECRET 2: What a number in a register stands for depends on the program that we have composed. SECRET 3: Since a number in a register can stand for anything, this means that the register machine can, in principle, be designed to “notice” anything, to “discriminate” any pattern or feature that can be associated with a number—or a number of numbers SECRET 4: Since a number can stand for anything, a number can stand for an instruction or an address. SECRET 5: All possible programs can be given a unique number as a name, which can then be treated as a list of instructions to be executed by a Universal machine. SECRET 6: All the improvements in computers since Turing invented his imaginary paper-tape machine are simply ways of making them faster. SECRET 7: There are no more secrets!
Philosopher Daniel Dennett's Book Intuition Pumps