I was reading Bogle this morning (still on chapter 3) and he referrenced William of Occam, a franciscan friar and philosopher famous for his Razor theory. Here it is in three forms:

“Entities should not be multiplied unnecessarily”

or put another way

“When faced with multiple solutions to a problem, choose the simplest one.”

the latin version translates as

“Plurality ought never be posited without necessity”

Bogle says of himself to start chapter 3 that “My career has been a monument, not to brilliance or complexity, but to common sense and simplicity, ‘the uncanny ability’, as one observer said of me, ‘to recognize the obvious.'”

This boils down for me today into one salient point:

Don’t invest in something you can’t understand. If it can’t be explained simply (even though there is always some complexity in the delivery) then it likely ought not be done.