I was discussing recently with someone how to find truth. The question was how an "ordinary" person could judge whether Steiner was likely correct or incorrect in some of his more far-out descriptions of spiritual beings. It was suggested that we could start with the things we could easily verify, namely how Steiner treats other authors. Is he fair to other authors? That is, in agreeing or disagreeing with another point of view, does he present that which he is opposing in a manner that fairly describes what the original author intended before beginning with his objections? Steiner wrote a considerable amount on philosophy and the history of philosophy (for example, his book "Riddles of Philosophy") so a person knowledgeable about philosophy in general could establish whether Steiner was generally trustworthy by how he treats other philosophers.
This type of test is useful for writers beyond Steiner as well. Take any of his critics, for example. Are they fair to other authors? That is, in agreeing or disagreeing with another point of view, do they present that which they are opposing in a manner that fairly describes what the original author intended before beginning with the objections? Do they pass this basic test of trustworthiness?