[PaulDavisThe1st]

> A major difference is that we created the machine and the code and, at least as low as the level of digital logic design, we understand and control its behavior.

The moment the software gets to interact with the world, whether via robotics or handling a mouse button event or some other type of sensor, we no longer fully understand or control its behavior.

Pure computation (the dream of functional programming) is fully understandable and entirely predictable. When you add interaction, you add both randomness but also time - when something happens can lead to different outcomes - and this can rapidly cause predictability to spiral away from us.