Recollection: a companionable form

Now let a man watch his mind while he is composing; or, to take a still more common case, while is trying to recollect a name...Most of my readers will have observed a small water-insect on the surface of rivulets, which throws a cinque-spotted shadow fringed with prismatic colours on the sunny bottom of the brook; and will have noticed how the little animal wins its way up against the stream, by alternate pulses of active and passive motion, now resisting the current and now yielding to it in order to gather further strength and a momentary fulcrum for a further propulsion. This is no unapt emblem of the mind's self-experience in the act of thinking.

-- from Coleridge's Biographia Literaria, quoted by Richard Holmes in A Meander through Memory and Forgetting.

The river Duddon