I don't think the article was saying that we "need to placate our talents as though we know nothing...", but rather be aware of the fact that there is always more to know. It's an uplifting, informal essay meant to inspire us. Obviously we're not looking for practical theory in it. But, your attitude absolutely influences everything you do-from how you treat your family to, yes, how you write music. I think that what the author of this article was trying to tell us is: put yourself in a position where you are able to continue to learn from your mistakes. It would destroy you as a composer if you stopped looking for your own mistakes, or stopped looking for new kinds of music because you "mastered" yours. The point is to never be too comfortable where you are, because then you'll never get anywhere new. Obviously we need to be wise about music, but it wouldn't hurt to stop thinking that we are.