Principles are ways of successfully dealing with reality to get what you want out of life.
Ray Dalio, one of the world’s most successful investors and entrepreneurs, cites principles as his key to success.
Learning is the product of a continuous real-time feedback loop in which we make decisions, see their outcomes, and improve our understanding of reality as a result. Being radically open-minded enhances the efficiency of those feedback loops, because it makes what you are doing, and why, so clear to yourself and others that there can't be any misunderstandings. The more open-minded you are, the less likely you are to deceive yourself-- and the more likely it is that others will give you honest feedback. If they are "believable" people (and it's very important to know who is "believable"), you will learn a lot from them.
Being radically transparent and radically open-minded accelerates this learning process. It can also be difficult because being radically transparent rather than more guarded exposes one to criticism. It's natural to fear that. Yet if you don't put yourself out there with your radical transparency, you won't learn.