Demographic, think of this: Science in the past was certain ( it was The Truth) about most things, just like we are today.
But today, we know that The Truth is different from the old Truth.
Right?
Now, how sure can we be it is the absolute, non changeable truth, the one we know today, the scientifically proved one?
Once, not so long time go, the Atom was the smallest unit. Then came the Protons, Neutrons, Electrons... The smallest units.
Then came the 'whatever' and they are the smallest units......