Here's another way to explain it: Since string theory is extremely tunable, you can just overfit it to all the data we already have about how the universe work

Here's another way to explain it: Since string theory is extremely tunable, you can just overfit it to all the data we already have about how the universe works. So the only way to get some certainty would be to have it make a prediction that we don't know the answer to, and then test it. At this point in time, we don't have the means to conduct such an experiment.