I was referring to the ST monad which bts and travisathougies were talking about, not STM. I mean that when you run ST code twice with the same input, you will

I was referring to the ST monad which bts and travisathougies were talking about, not STM. I mean that when you run ST code twice with the same input, you will get the same output. E.g., if I write (runST f) + (runST f), that's the same as 2 * (runST f), etc. As for thinking, it means I don't use step-through debuggers ever, because I don't need the whole program to be in a certain state to watch what happens. I just grab the function, grab the input, and run it in isolation.