Gazing at a Crystal Ball

What is software engineering? A mixture of science and craftsmanship, built on rules and logic. Once done, we expect a program to run the same predictable way, over and over again. Applications therefore are deterministic: the same input leads to the same output (if we treat state and side effects as input). But we still somehow have bugs, not because the app magically changes its behavior, but because programs are complex, and because we are humans. So we call software deterministic, and treat