The Idea is capable of existing almost everywhere and at all times and can even spontaneously create itself quite independently of migration and tradition.

An Idea is always a generalization, and generalization is a property of thinking, so to generalize means to think.
The Idea is easily killed by brute force (contrary to popular belief) and once an idea is dead it is no more than a corpse.
The Idea is incapable of being new... we simply take a lot of old ideas and put them into a sort of mental kaleidoscope.

The Idea is a mask that always hides something. It is able to attain this degree of transformational power over the body only if it is couched in a linguistic form of great beauty and pithiness.
An Idea is a perception of the mind which involves thinking of something instead of actuality (first hand) experiencing it.
An Idea is everything that is an object of thought. An idea is that which one is immediately conscious of within himself.