Steiner does write about truth and he seems to mean knowledge. He uses “truth” for “knowledge”. That is not as strange as it sounds, most of us do use “truth” when we mean “knowledge”. If we want to know the truth about something, we could also say that we want to know all about something. That is confusing.
Why is that confusing? Critical Rationalism wants us to make a clear difference between truth and knowledge. Truth does exist, but we cannot know if our knowledge is true. That is, in a nutshell, the word of critical rationalism about truth and knowledge.
You will understand that confusing “truth” with “knowledge” will make it difficult to understand the critical rationalist view.
“If this isn’t 100% true, it’s true enough to be interesting—and maybe helpful.” ( Kurt Vonnegut, 1951 in: Look at the Birdie)
Vonnegut writes about an idea (in Letter from Kurt Vonnegut, Jr., to Walter J. Miller, 1951). The idea could be true or it could be not 100% true. Vonnegut uses true as a quality. And Vonnegut could be a critical rationalist when he writes this statement. We cannot know if our knowledge is true, but we could try to use it until experience does teach us our knowledge is not true.
Truth is a very complicated subject. You should read Wikipedia about truth and think about how people ever in a matter of fact way could talk about truth. Wikipedia mentions (today) seven theories about truth. What does it mean if a judge does want you to tell the truth, the whole truth and nothing but the truth? 😉 According to what definition of truth?