What does Thoreau mean when he says that the "universe constantly and obediently answers to our conceptions"?

This quote appears in Chapter 2 of Walden
in which Thoreau discusses where he goes and why he goes into the woods.
These words in particular represent one of the main tenets of Transcendentalism and echo
some of Emerson's statements in Nature. What Thoreau means is that
self-reliant man has only to set out on whatever path he chooses because nature (or "the
universe") will ensure that that path is already there. Thus, there are no limitations
on man's goals or journey. The following clause, "whether we travel fast or slow, the
track is laid for us," demonstrates Thoreau's philosophy of every man marching to his
own beat and once again illustrates that man need not worry that  some higher power will
disrupt his rhythm or hinder his thinking ("conceptions"). Instead, man's universe
becomes whatever he wants it to be.

This type of
thinking--that man possesses a unity with the universe and that it is his to conceive or
bend--would have been shocking, of course, to the Puritan or Romantic authors who
preceded Thoreau. So, his words serve as a contrast to their view that the universe or
God controls man and forces him to consistently obey.