What does Jerry Garcia play on "Eyes of the World" and why does it sound so cool?

Understanding the "Eyes mode"

What makes Jerry Garcia's guitar style so magical? What makes a person like me slog through so much indifferent-to-terrible Grateful Dead music to hear it? Rather than try to understand the whole corpus at once, I think it makes more sense to zoom in on specific phrases and passages and see how they work. In a previous post, I examined a phrase from the studio version of "The Music Never Stopped". In this post, I look at the intro to "Eyes of the World" from 11/11/1973. 

I'm not going to talk about "Eyes of the World" as a song; I'll save that for another post. Instead, I'm only concerned with Jerry's solo in the first minute.