> Broadly speaking, with AD you can modify the results and the program will spit out the required inputs to get those results. I assume you're trying to phrase

> Broadly speaking, with AD you can modify the results and the program will spit out the required inputs to get those results. I assume you're trying to phrase it in a non-technical way for accessibility, but I wonder if that might have lost some precision. What you describe sounds more like (logically) reversible programming (https://en.wikipedia.org/wiki/Reversible_computing https://en.wikipedia.org/wiki/Reversible_computing). Differentiability doesn't imply reversibility; for example, the program that takes in an input and returns 1 is as differentiable as they come, but there's nothing that differentiation, automatic or otherwise, can do to tell you an input that will make it return 2.