The scientific theorist is not to be envied. For Nature, or more precisely experiment, is an inexorable and not very friendly judge of his work. It never says "Yes" to a theory. In the most favorable cases it says "Maybe," and in the great majority of cases simply "No." If an experiment agrees with a theory it means for the latter "Maybe," and if it does not agree it means "No." Probably every theory will some day experience its "No"—most theories, soon after conception.
Albert Einstein, November 11, 1922
I think you'd agree scientists are almost always very smart people. And probably, most scientists themselves would agree with us about their being very smart. That's okay. They're entitled to know they're smart.
Sometimes though, even a smart scientist can have a blind spot. For example, maybe the smart scientist in the picture has a hypothesis she wants to test. Let's pretend her name is Sally Simpson. Sally designs an experiment to find out whether her hypothesis is true or false. Now let's say she conducts her experiment and it shows her hypothesis was true! She thinks, "Hey, I was right!"
Sally Simpson is a smart scientist, so she repeats the experiment many times just to be sure. Every time she gets the same results! Then she tells other scientists and many of them decide to repeat her experiment and they get the same results, too!
Smart scientist Sally Simpson is now becoming somewhat of a sensation in scientific circles. She even starts socializing at the seminars of certain scientific societies!
Eventually, she gets invited to be a guest on Good Morning America. Robin Roberts introduces Sally Simpson by announcing to America her hypothesis is positively proven by the exciting experiment and the repeatable results! Everybody applauds!
But then George Stephanopoulos chimes in: "According to astrophysicist Ethan Siegel, '...when it comes to science, proving anything is an impossibility.' So your experiment doesn't really PROVE your hypothesis, does it, Sally Simpson?" Sally is simply shocked at Stephanopoulos' snide suggestion. She's speechless! Then Michael Strahan suggests segueing to a second segment.
Friends, in this fictional scenario, smart scientist Sally Simpson's reputation is ruined by Robin Roberts' reckless remark regarding repeatable results pointing to positive proof.
And I for one think we've all shared in something important today. No idea what it was though.
Editor's note: Click on the underlined link in George Stephanopoulos' imaginary quote to visit Forbes.com, where Ethan Siegel fully explains why science can't really offer proof of anything.