[jawbone3]

I guess you train it on things you know and use it to tell if a new observation looks familiar or not. You can't use the NN for the final analysis because its just a pile of linear algebra shaped like a causal theory: there is no actual physics in it.

[yh_82367]

yes, in principle you're right. But in this case, the answer from the neural nets is so incredibly close to the true answer, that we think we can trust it for most purposes. If someone really wanted the most accurate answer, then they can start from the NN answer and do a proper model fitting procedure, which of course fits a simulated model with all the appropriate physics in it to the data.

[jawbone3]

Well, in the important case of finding something new and interesting you need proper MC to verify your understanding. In practice you are right that using the NN like it actually speaks about reality will be common and not too harmful, people do lots of dubious least squares fits and astronomy still survives!