Question

That spectacle for many days my brain worked with a dim and undetermined sense

Answer 1

That spectacle for many days my brain worked with a dim and undetermined sense" these lines are from the poem "The Prelude" authored by Willian Wordsworth.

This poem if a considered as one of the best creatins of English literature.

This poem is about nature and humans. nature deserves much more respect than we.

Dim and undetermined sense indicates the same.