Wisdom is about sufficiently understanding enough things to be able to see a topic / subject with a wide and balanced perspective.
Two of the most valuable perspectives one can bring to bear are those of history and experience. There’s lots of knowledge that can be acquired rapidly, assuming one has some reasonable I.Q. to assist. It generally takes time for anyone to accumulate the perspective of years. Understanding how the ‘now’ of one’s youth has become the distant history of one’s grandchildren takes time. This perspective enables one to understand the realities of history, including history in the making.
This perspective combines with another very powerful perspective - experience. Black Swan events only happen from time to time, yet they do happen with both chaotic inevitability and specific unpredictability - like avalanches. In a long life one will have seen many accidents, many economic depressions / recessions, many births and deaths. Each is different, and yet somewhat similar. Eventually, as the harbingers of a new economic crisis begin to cause panic, the experienced are saying - “Saw this in the seventies and late eighties, the OPEC Oil crisis, the dot.com bust, the 2008 Global Financial Crisis, … . My Mom and Dad lived through the great Depression. This isn’t new. Somewhat different perhaps, but not new.”
Powerful perspectives, but they do require the passage of years to acquire. The image of the ageing man with the long white beard is the iconic image of the tribal elder, the Moses prophet figure, the wisdom of the ages present in our company.
And hence the image association with wisdom.
Celestial Koan tries to avoid the long white bearded look, and stick with images of the moon.