In Platonic thought an idea is defined as an eternally existing pattern of which individual things in any class are imperfect copies. Immanuel Kant described an idea as a concept of pure reason, not empirically based in experience. I find Charles Dickens’ take on the matter particularly illuminating: “An idea, like a ghost, must be spoken to a little before it will explain itself.”
This conversation is, as is the case with most worthwhile pursuits, often daunting but as Oliver Wendell Holmes said, “One’s mind, once stretched by a new idea, never regains its original dimensions. This stretching of the mind is what, in the words of Albert Schweitzer, gives us the capacity to stop taking our existence for granted, to behold it as something unfathomably mysterious and in so doing liberate our minds.
Nothing else in the world… not all the armies… is so powerful as an idea whose time has come. – Victor Hugo
An idea that is not dangerous is unworthy of being called an idea at all. – Oscar Wilde