Freedom might be said to describe not only the size of our “option set” but also our awareness of what options there are. That awareness has two degrees. One is conceptual: if you don’t know about a thing, like chocolate ice cream, you can hardly ask for it, much less feel oppressed by the want of it. The second degree of awareness comes after we know about things conceptually and can begin to contemplate them as real choices. I may be aware that man has gone into space but the idea that I might choose to go there myself, while conceivable, is only a notion until I find out that Virgin Galactic has started scheduling flights.

Tim Wu, The Attention Merchants, loc. 422