I have to say that the New England Transcendentalists in general had no idea what the texts that they were using to base their philosophies on were really about. Emerson was one of the better ones, and still has a lot of very good ideas, but, seriously, the Transcendental Idealism of the New England folks is a bizarre mixture of half understood concepts from Idealist philosophy mixed with lots of other random stuff. "Transcendental" in Idealist thought had to do with the "Transcendental Perspective", which came from Kant, and which the perspective of folks who look at how their mental processes work and try to categorize it. It's transcendental because it's not linked to any particular exterior information, but, as Kant repeats many times, is the form for the substance of this information. On the other hand, it's not bound to pure animal reflex, and so deals with a kind of higher psychology. It transcends both our particular experiences, on the one hand, and our biological, material, programming, instead having to do with the realm of cognition that exists between the two.