> "Evidence" is anything that should cause you to update your beliefs.
No, this is too broad. We are talking about testing scientific theories, not just updating a random person's beliefs. "Evidence" is what you compare theoretical predictions with to test theories.
> The simulations show that a certain possible phenomenon is consistent with known physics when this was not known before
More or less, yes.
> and therefore they raise the likelihood that the phenomenon exists.
No, this is a non sequitur. Knowing that a phenomenon is consistent with the laws of physics tells you nothing about whether that phenomenon actually exists. The set of phenomena that actually exist is too tiny compared to the set of phenomena that are consistent with the laws of physics for knowing something is a member of the latter to give any useful information about the former.
Your argument ultimately comes down to an argument from authority about the use of the word "evidence". Arguments about word definitions are uninteresting. What is substantively at stake is if a simulation like the one in the paper can provide information about a scientific phenomenon. Because a pure simulation can cause a change in beliefs, it does provide information.
> Your argument ultimately comes down to an argument from authority about the use of the word "evidence".
No, it comes down to an important substantive point about what the word "evidence" implies and that that implication is not valid. See below.
> What is substantively at stake is if a simulation like the one in the paper can provide information about a scientific phenomenon.
And the answer to that is obvious: a simulation can provide information about what a particular scientific theory predicts. It cannot provide information about what the real world actually does. Only the real world can do that. But using the word "evidence" to describe the output of a computer simulation obfuscates that vital distinction. That is why I objected to it.
For a real-world example of why obfuscating this distinction is not a good idea, see kadonoishi's post downthread.
> a simulation can provide information about what a particular scientific theory predicts. It cannot provide information about what the real world actually does.
If the simulation had come out in the negative, and it turned out this phase of H20 was totally inconsistent with all known physics, that would cause any reasonable person to assign a lower probability to the proposition that this phenomenon exists in the world. That's providing information about the world. Since the outcome would provide information in the negative, it also does in the positive.
I agree that there's an important distinction to be drawn between observational evidence vs. outcomes of simulations in terms of how they provide information, but they both provide information that was not accessible before.
> Since the outcome would provide information in the negative, it also does in the positive.
No, this doesn't follow. The two cases are not symmetric. Ruling out a phenomenon (if we assume for the sake of argument that a "negative" simulation result can actually do this--in reality things are quite a bit more complex, the simulation was not run as a binary yes/no test of a "phenomenon") rules it out. But showing that a phenomenon is possible doesn't tell you anything useful about whether it actually happens.
No, this is too broad. We are talking about testing scientific theories, not just updating a random person's beliefs. "Evidence" is what you compare theoretical predictions with to test theories.
> The simulations show that a certain possible phenomenon is consistent with known physics when this was not known before
More or less, yes.
> and therefore they raise the likelihood that the phenomenon exists.
No, this is a non sequitur. Knowing that a phenomenon is consistent with the laws of physics tells you nothing about whether that phenomenon actually exists. The set of phenomena that actually exist is too tiny compared to the set of phenomena that are consistent with the laws of physics for knowing something is a member of the latter to give any useful information about the former.