What?
Scientific work can be verified, it can be repeated, the evidence can be shown.
This is called science, and peer review.
An experiment in science is repeatable, over, and over, and over again.
Which is why science is important, and why it does not have to be taken on faith.
All you have to do is understand the perameters of the experiment, have the equipment, and you too can repeat any scientific experiment there is.
That doesn't mean it didn't happen, just that certain events are simply unverifiable.
Now if you're talking about something being "close enough for government work" that's another matter which is not under discussion.