It's very good for an idea to be commonplace. The important thing is that a new idea should develop out of what is already there so that it soon becomes an old acquaintance. Old acquaintances aren't by any means always welcome, but at least one can't be mistaken as to who or what they are.
There are more ideas on earth than intellectuals imagine. And these ideas are more active, stronger, more resistant, more passionate than politicians think. We have to be there at the birth of ideas, the bursting outward of their force: not in books expressing them, but in events manifesting this force, in struggles carried on around ideas, for or against them. Ideas do not rule the world. But it is because the world has ideas... that it is not passively ruled by those who are its leaders or those who would like to teach it, once and for all, what it must think.
It is not always by plugging away at a difficulty and sticking to it that one overcomes it; often it is by working on the one next to it. Some things and some people have to be approached obliquely, at an angle.
Whenever I hear people talking about liberal ideas, I am always astounded that men should love to fool themselves with empty sounds. An idea should never be liberal; it must be vigorous, positive, and without loose ends so that it may fulfill its divine mission and be productive. The proper place for liberality is in the realm of the emotions.