Actually, that is Epistemology.
It is correct that in philosophy of science nothing can be known to be 100% true with Certitude.
But its false to say we can't verify, and only refute. That is a mental-con and false-statement. Is that from Byron Katie?
Science is based on both falsification and verification.
Einstein's Relativity has been VERIFIED thousands of times, and NEVER REFUTED. NEVER.
If you could refute it with evidence, you would win the Nobel Prize.
But does that mean its 100% true for eternity? No. But close!
Its more like a continuum, from 0% likely to 100%.
Nothing is 0% or 100%, but falls in between.
So things like hard science are up in the 90%.
Gravity around 99.999999999999999. (this is why those who claim to levitate are all liars. All? Yes, not one has ever proven it. Ever, not one, they just lie and people believe them).
Most social science really is not much higher than 50%.
Where might Eckhart Tolloe be on that? Very close to 0%.
He provides ZERO evidence or proof.
His words are self-contradictory.
He decries the Mind-Ego using the Mind-Ego.
Folks like Byron Katie try to con people with deception, like saying science only falsifies. That is false. That is taken from Popper who said a scientific theory has to be falsifiable, but that is completely different.
Do Eckart and Byron Katie produce theories that are falsifiable? NO THEY DO NOT. They are untestable, thus they are useless.
You see, they pervert Knowledge to make money off people, and they seem to do it very consciously with mind-tricks and word-tricks.
Perhaps the most powerful tool of all is: 'is it true'?
To get back to science, logic and rationality again, philosophers of science (or are they flakes too?) accept, and have accepted, since the middle of the last century, that we can't know if anything is true. We can only find out where we are mistaken. We can't verify--we can only refute, based on the evidence. Another way to put it: everything is provisional. There can always be evidence to contradict even the most basic common sense.
Byron Katie's work essentially asks you to apply that to your own thoughts. Question and look for the counter-evidence. It's a powerful way to go through life. You're obviously willing to do it to get to your denunciations, but then you make the mistake that we all do, until we don't: you accept your resulting beliefs, and don't question those.
Or am I wrong?