in Thoreau’s Journal:

I must walk more with free senses–– It is as bad to study stars & clouds as flowers & stones–– I must let my senses wander as my thoughts––my eyes see without looking. Carlyle said that how to observe was to look––but I say that is rather to see––& the more you look the less you will observe––

I have the habit of attention to such excess that my senses get no rest––but suffer from a constant strain.  Be not preoccupied with looking. Go not to the object.  Let it come to you….What I need is not to look at all––but a true sauntering of the eye.