The video gives a paraphrased (& clearer) version of the original essay below - which says the English Lit. guy doesn't see that the various "wrongs" aren't equally wrong, far from it; science progresses toward "more correct".
(And science makes this progress - this continual improvement - because its culture encourages people to point out flaws, and to correct them.)
The Relativity of Wrong
"In short, my English Lit friend, living in a mental world of absolute rights and wrongs, may be imagining that because all theories are wrong, the earth may be thought spherical now, but cubical next century, and a hollow icosahedron the next, and a doughnut shape the one after.
What actually happens is that once scientists get hold of a good concept they gradually refine and extend it with greater and greater subtlety as their instruments of measurement improve. Theories are not so much wrong as incomplete.
This can be pointed out in many cases other than just the shape of the earth. Even when a new theory seems to represent a revolution, it usually arises out of small refinements. If something more than a small refinement were needed, then the old theory would never have endured."