It's evidence if it can be used to falsify theories, imo. That is true of some computational science, i.e. if you use a computer to make predictions from a theory to compare the predictions with observations.
There is already a word for what you are describing, and that's proof. Evidence is a far broader term. It can be weak, strong, misleading or just indicative.
If I have a problem with the title it's the word "shows", this evidence indicates a behaviour water may have, it doesn't show that it has it.
> It's evidence if it can be used to falsify theories
No, this is too broad, because falsifying theories takes two elements: a prediction, and the evidence that the prediction gets compared to. Only the second is evidence; the first is not. And simulations only give you the first.
> if you can falsify theories subject to the assumptions of the simulation, that’s still evidence.
No, the falsification itself is not evidence; it's a falsification. Evidence is what you compare the predictions of the simulation to, and then you call the theory falsified if the two don't match.
I spent some years doing computer simulations of cancer screening. The confusion between the output of the simulation, which is not evidence, and real evidence, led me into a nightmare of the Hall of Mirrors, where everything I attempted to learn about cancer screening turned out to be merely a reflection of my own assumptions. Everywhere I turned it was another funhouse mirror, where the computer warped my own ideas because the code I wrote was not a perfect flat reflection of what I meant, because my code introduced distortions, which took immense rigor to avoid.
The confusion between real evidence, and the output of my computer simulation which was not evidence but I _confused_ it with evidence, led me down a dark path lost in a labyrinth of funhouse mirrors of my own construction.
