One of the chief ways in which we can see the truth of these words in today's world is through the way that society today, and in fact any society, seems designed to create a "multitude" that is merely "credulous" and will be passive sheep who do not try and challenge anything and will accept what is presented to them. It will only be a few defiant and brave individuals who will challenge the status quo and be brave enough to be "artful" in going against the flow and the various social pressures that try and make them conform.
Yet, what is so important about this quote from John Adams, is the way that change in society and its improvement is only possible through those who are "artful" enough to challenge society and to try and move it in a different direction. The importance of this quote therefore lies in the way that it places great value on the minority who are able to defy the conforming nature of society. It is to these that we need to look to for our survival to ensure that we do change and progress as a society.