麻烦解释一下下面这段话

麻烦解释一下下面这段话Now custom has not been commonly regarded as a subject of any great importantance. The inner workings of our own brains we feel to be uniquely worthy of investigation, but custom, we have a way of thinking, is behavior at its most taken the world over, is a mass of detailed behavior more astonishing than what any one person can ever evole in individual actions. Yet that is a rather trivial aspect of the matter. The fact of first-rate importance is the predominant role that custom plays in experience and in belief and the very great varieties it may manifest.